# 80 FR 22304: Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale (Megaptera novaeangliae) and Proposed Revision of Species-Wide Listing

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URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-09010

## Section

- **Citation:** 80 FR 22304
- **Heading:** Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale (Megaptera novaeangliae) and Proposed Revision of Species-Wide Listing
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 80 / 80 FR 22304

## Text

DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Parts 223 and 224 [Docket No. 130708594-5298-02 ] RIN 0648-XC751 Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale ( Megaptera novaeangliae ) and Proposed Revision of Species-Wide Listing AGENCY:
National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.

ACTION:
Proposed rule; 12-month findings.

SUMMARY:
We, NMFS, have completed a comprehensive status review of the humpback whale ( Megaptera novaeangliae ) under the Endangered Species Act of 1973, as amended (ESA) (16 U.S.C. 1531 et seq. ) and announce a proposal to revise the listing status of the species. We propose to divide the globally listed endangered species into 14 distinct population segments (DPSs), remove the current species-level listing, and in its place list 2 DPSs as endangered and 2 DPSs as threatened. The remaining 10 DPSs are not proposed for listing based on their current statuses. This proposal also constitutes a negative 12-month finding on a petition to delineate and “delist” a DPS of humpback whales spanning the entire North Pacific and a positive 12-month finding on a petition to delineate and “delist” a DPS in the Central North Pacific (Hawaii breeding population).
At this time, we do not propose to designate critical habitat for the two listed DPSs that occur in U.S. waters (Western North Pacific, Central America) because it is not currently determinable. In order to complete the critical habitat designation process, we also solicit information on essential physical and biological features of the habitat of these two DPSs.

DATES:
Comments must be submitted to NMFS by July 20, 2015. For specific dates of the public hearings, see SUPPLEMENTARY INFORMATION . Requests for additional public hearings must be made in writing and received by June 5, 2015
rder to complete the critical habitat designation process, we also solicit information on essential physical and biological features of the habitat of these two DPSs.

DATES:
Comments must be submitted to NMFS by July 20, 2015. For specific dates of the public hearings, see SUPPLEMENTARY INFORMATION . Requests for additional public hearings must be made in writing and received by June 5, 2015.

ADDRESSES:
Four public hearings will be held, one each in Juneau, AK, Honolulu, HI, Plymouth, MA, and Virginia Beach, VA. For specific locations of these hearings, see SUPPLEMENTARY INFORMATION .
You may submit comments, identified by NOAA-NMFS-2015-0035, by any of the following methods:
Electronic Submission: Submit all electronic public comments via the Federal eRulemaking Portal.
1. Go to www.regulations.gov/#!docketDetail;D= NOAA-NMFS-2015-0035,
2. Click the “Comment Now!” icon, complete the required fields
3. Enter or attach your comments.
—Or— Mail: Submit written comments to Marta Nammack, NMFS, 1315 East-West Highway, Room 13536, Silver Spring, MD 20910.
Instructions: Comments sent by any other method, to any other address or individual, or received after the end of the comment period, may not be considered by NMFS. All comments received are a part of the public record and will generally be posted for public viewing on www.regulations.gov without change. All personal identifying information ( e.g., name, address, etc.), confidential business information, or otherwise sensitive information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous).
The proposed rule, Status Review report and other materials relating to this proposal can be found on the NMFS Web site at: http://nmfs.noaa.gov/pr/.
FOR FURTHER INFORMATION CONTACT:
Marta Nammack, NMFS, (301) 427-8469
tion submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous).
The proposed rule, Status Review report and other materials relating to this proposal can be found on the NMFS Web site at: http://nmfs.noaa.gov/pr/.
FOR FURTHER INFORMATION CONTACT:
Marta Nammack, NMFS, (301) 427-8469.

SUPPLEMENTARY INFORMATION:
On August 12, 2009, we announced the initiation of a status review of the humpback whale to determine whether an endangered listing for the entire species was still appropriate (74 FR 40568). We sought information from the public to inform our review, hired two post-doctoral students to compile the best available scientific and commercial information on the species (Fleming and Jackson, 2011), including the past, present, and foreseeable future threats to this species, and appointed a Biological Review Team (BRT) to analyze that information, make conclusions on extinction risk, and prepare a status review report (Bettridge et al., 2015).
On April 16, 2013, we received a petition from the Hawaii Fishermen's Alliance for Conservation and Tradition, Inc., to classify the North Pacific humpback whale population as a DPS and “delist” the DPS under the Endangered Species Act (ESA). On February 26, 2014, the State of Alaska submitted a petition to delineate the Central North Pacific (Hawaii) stock of the humpback whale as a DPS and remove the DPS from the List of Endangered and Threatened Species under the ESA. After reviewing the petitions, the literature cited in the petitions, and other literature and information available in our files, we found that both petitioned actions may be warranted and issued positive 90-day findings (78 FR 53391, August 29, 2013; 79 FR 36281, June 26, 2014). We extended the deadline for receiving information by 30 days to help us respond to the petition to delist the Central North Pacific population (79 FR 40054; July 11, 2014)
the petitions, and other literature and information available in our files, we found that both petitioned actions may be warranted and issued positive 90-day findings (78 FR 53391, August 29, 2013; 79 FR 36281, June 26, 2014). We extended the deadline for receiving information by 30 days to help us respond to the petition to delist the Central North Pacific population (79 FR 40054; July 11, 2014). We incorporated the consideration of both petitioned actions into the status review.
Based on information presented in the status review report, an assessment of the ESA section 4(a)(1) factors, and efforts being made to protect the species, we have determined: (1) 14 populations of the humpback whale meet the DPS policy criteria and are therefore considered to be DPSs; (2) the Cape Verde Islands/Northwest Africa and Arabian Sea DPSs are in danger of extinction throughout their ranges; (3) the Western North Pacific and Central America DPSs are likely to become endangered throughout all of their ranges in the foreseeable future; and (4) the West Indies, Hawaii, Mexico, Brazil, Gabon/Southwest Africa, Southeast Africa/Madagascar, West Australia, East Australia, Oceania, and Southeastern Pacific DPSs are not in danger of extinction throughout all or a significant portion of their ranges or likely to become so in the foreseeable future. Accordingly, we issue a proposed rule to revise the species-wide listing of the humpback whale by replacing it with 2 endangered species listings (Cape Verde Islands/Northwest Africa and Arabian Sea DPSs) and 2 threatened species listings (Western North Pacific and Central America DPSs). We solicit comments on these proposed actions. We also propose to extend the ESA section 9 prohibitions to the 2 threatened DPSs
ssue a proposed rule to revise the species-wide listing of the humpback whale by replacing it with 2 endangered species listings (Cape Verde Islands/Northwest Africa and Arabian Sea DPSs) and 2 threatened species listings (Western North Pacific and Central America DPSs). We solicit comments on these proposed actions. We also propose to extend the ESA section 9 prohibitions to the 2 threatened DPSs.
Outline
ESA Statutory Provisions, Regulations, and Policy Considerations Distinct Population Segment Policy “Foreseeable Future” “Significant Portion of its Range” Background Behavior Feeding Reproduction Natural Mortality Status Review Report Humpback Whale Subspecies Reproductive Seasonality Behavior Color patterns Genetics Subspecies Discussion and Conclusions Distinct Population Segment Analysis, By Subspecies North Atlantic Overview Discreteness Significance North Pacific Overview Discreteness Significance Southern Hemisphere Overview: Discreteness Significance Extinction Risk Assessment Abundance and Trends for Each DPS West Indies DPS Cape Verde Islands/Northwest Africa DPS Western North Pacific DPS Hawaii DPS Mexico DPS Central America DPS Brazil DPS Gabon/Southwest Africa DPS Southeast Africa/Madagascar DPS West Australia DPS East Australia DPS Oceania DPS Southeastern Pacific DPS Arabian Sea DPS Summary of Abundance and Trends Summary of Section 4(a)(1) Factors Affecting the 14 Humpback Whale DPSs Section 4(a)(1) Factors Applicable to All DPSs A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes: C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence West Indies DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D
Scientific, or Educational Purposes: C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence West Indies DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Cape Verde Islands/Northwest Africa DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Western North Pacific DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Hawaii DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Mexico DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Central America DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B
on, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Central America DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Brazil DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Gabon/Southwest Africa DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Southeast Africa/Madagascar DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence West Australia DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence East Australia DPS A
tors Affecting its Continued Existence West Australia DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence East Australia DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Oceania DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Southeastern Pacific DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Arabian Sea DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E
or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Arabian Sea DPS A. The present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes C. Disease or Predation D. Inadequacy of Existing Regulatory Mechanisms E. Other Natural or Manmade Factors Affecting its Continued Existence Ongoing Conservation Efforts Rationale for Revising the Current Global Listing and Replacing It with Listings of DPSs Conclusions on the Status of Each DPS under the ESA Endangered DPSs Threatened DPSs DPSs Not Warranted for Listing under the ESA Post-delisting Monitoring Plan Description of Proposed Regulatory Changes Prohibitions and Protective Measures Identification of Those Activities That Would Constitute a Violation of Section 9 of the ESA Effects of this Rulemaking Peer Review Critical Habitat Public Comments Solicited Public Hearings Classification National Environmental Policy Act (NEPA) Executive Order (E.O.) 12866, Regulatory Flexibility Act, and Paperwork Reduction Act E.O. 13132, Federalism E.O. 13175, Consultation and Coordination with Indian Tribal Governments ESA Statutory Provisions, Regulations, and Policy Considerations
Pursuant to the ESA, any interested person may petition to list or delist a species, subspecies, or DPS of a vertebrate species that interbreeds when mature (5 U.S.C. 553(e), 16 U.S.C. 1533(b)(3)(A)). ESA-implementing regulations issued by NMFS and the U.S. Fish and Wildlife Service (FWS) also establish procedures for receiving and considering petitions to revise the lists of endangered and threatened species and for conducting periodic reviews of listed species (50 CFR 424.01)
s, subspecies, or DPS of a vertebrate species that interbreeds when mature (5 U.S.C. 553(e), 16 U.S.C. 1533(b)(3)(A)). ESA-implementing regulations issued by NMFS and the U.S. Fish and Wildlife Service (FWS) also establish procedures for receiving and considering petitions to revise the lists of endangered and threatened species and for conducting periodic reviews of listed species (50 CFR 424.01).
Once we receive a petition to delist a species, the ESA requires the Secretary of Commerce (Secretary) to make a finding on whether the petition presents substantial scientific or commercial information indicating that the petitioned action may be warranted (16 U.S.C. 1533(b)(3)(A)). In the context of a petition to delist a species, the ESA-implementing regulations provide that “substantial information” is that amount of information that would lead a reasonable person to believe that delisting may be warranted (50 CFR 424.14(b)(1)). In determining whether substantial information exists, we take into account several factors, in light of any information noted in the petition or otherwise readily available in our files. To the maximum extent practicable, this finding is to be made within 90 days of the receipt of the petition (16 U.S.C. 1533(b)(3)(A)) and published promptly in the Federal Register . Section 4(b)(3)(B) of the ESA requires that, when a petition to revise the List of Endangered and Threatened Wildlife and Plants is found to present substantial scientific and commercial information, we make a finding that the petitioned action is (a) not warranted, (b) warranted, or (c) warranted but precluded from immediate proposal by other pending proposals of higher priority. This finding (the “12-month finding”) is to be made within 1 year of the date the petition was received, and the finding is to be published promptly in the Federal Register . The Secretary has delegated the authority for these actions to the NOAA Assistant Administrator for Fisheries
b) warranted, or (c) warranted but precluded from immediate proposal by other pending proposals of higher priority. This finding (the “12-month finding”) is to be made within 1 year of the date the petition was received, and the finding is to be published promptly in the Federal Register . The Secretary has delegated the authority for these actions to the NOAA Assistant Administrator for Fisheries.
Section 3 of the ESA defines an endangered species as “any species which is in danger of extinction throughout all or a significant portion of its range” and a threatened species as one “which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” Thus, we interpret an “endangered species” to be one that is presently in danger of extinction. A “threatened species,” on the other hand, is not presently in danger of extinction, but is likely to become so in the foreseeable future (that is, at a later time). In other words, the primary statutory difference between a threatened and endangered species is the timing of when a species may be in danger of extinction, either presently (endangered) or in the foreseeable future (threatened). In determining whether to reclassify or delist a species, subspecies, or DPS, the ESA and implementing regulations require that we consider the following ESA section 4(a)(1) factors in relation to the definitions of “endangered species” or “threatened species” (16 U.S.C. 1533(a)(1) and 1533(c)(2); 50 CFR 424.11(d)): The present or threatened destruction, modification, or curtailment of its habitat or range; overutilization of the species for commercial, recreational, scientific, or educational purposes; disease or predation; the inadequacy of existing regulatory mechanisms; and other natural or manmade factors affecting a species' continued existence
s” (16 U.S.C. 1533(a)(1) and 1533(c)(2); 50 CFR 424.11(d)): The present or threatened destruction, modification, or curtailment of its habitat or range; overutilization of the species for commercial, recreational, scientific, or educational purposes; disease or predation; the inadequacy of existing regulatory mechanisms; and other natural or manmade factors affecting a species' continued existence. These are the same factors that we must consider when making an initial determination whether to list a species, subspecies, or DPS as threatened or endangered under the ESA.
Section 4(b)(1)(A) of the ESA requires us to make listing determinations based solely on the best scientific and commercial data available after conducting a review of the status of the species and after taking into account efforts being made by any State or foreign nation or political subdivision thereof to protect the species. In evaluating the efficacy of protective efforts not yet implemented or not yet proven to be effective, we rely on the Policy on Evaluation of Conservation Efforts When Making Listing Decisions (“PECE”; 68 FR 15100; March 28, 2003) issued jointly by NMFS and the FWS (together, the Services). The ESA regulations require that a species listed as endangered or threatened be removed from the list if the best scientific or commercial data available indicate that the species is no longer endangered or threatened because it has recovered (50 CFR 424.11(d)).
Distinct Population Segment Policy
To be considered for listing under the ESA, a group of organisms must constitute a “species,” which the ESA defines to include “. . . any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature” (16 U.S.C. 1532 (16)). Thus, an ESA listing (or delisting) determination can address a species, subspecies, or a DPS of a vertebrate species
r the ESA, a group of organisms must constitute a “species,” which the ESA defines to include “. . . any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature” (16 U.S.C. 1532 (16)). Thus, an ESA listing (or delisting) determination can address a species, subspecies, or a DPS of a vertebrate species.
On February 7, 1996, the Services adopted a policy describing what constitutes a DPS of a taxonomic species (61 FR 4722). The joint DPS policy identified two elements that must be considered when identifying a DPS: (1) The discreteness of the population segment in relation to the remainder of the species (or subspecies) to which it belongs; and (2) the significance of the population segment to the remainder of the species (or subspecies) to which it belongs. A population segment of a vertebrate species may be considered discrete if it satisfies either one of the following conditions:
(1) It is markedly separated from other populations of the same taxon as a consequence of physical, physiological, ecological, or behavioral factors. Quantitative measures of genetic or morphological discontinuity may provide evidence of this separation.
(2) It is delimited by international governmental boundaries within which differences in control of exploitation, management of habitat, conservation status, or regulatory mechanisms exist that are significant in light of section 4(a)(1)(D) of the ESA.
If a population segment is considered discrete under one or more of the above conditions, its biological and ecological significance is then considered in light of Congressional guidance (see Senate Report 151, 96th Congress, 1st Session) that the authority to list DPSs be used “sparingly” while encouraging the conservation of genetic diversity. This consideration may include, but is not limited to, the following:
(1) Persistence of the discrete population segment in an ecological setting unusual or unique for the taxon;
nce is then considered in light of Congressional guidance (see Senate Report 151, 96th Congress, 1st Session) that the authority to list DPSs be used “sparingly” while encouraging the conservation of genetic diversity. This consideration may include, but is not limited to, the following:
(1) Persistence of the discrete population segment in an ecological setting unusual or unique for the taxon;
(2) Evidence that loss of the discrete population segment would result in a significant gap in the range of a taxon;
(3) Evidence that the discrete population segment represents the only surviving natural occurrence of a taxon that may be more abundant elsewhere as an introduced population outside its historic range; or
(4) Evidence that the discrete population segment differs markedly from other populations of the species in its genetic characteristics.
“Foreseeable Future”
To determine whether listing of a species is warranted, a status review must conclude that the species is “in danger of extinction or likely to become so within the foreseeable future throughout all or a significant portion of its range.” The ESA uses the term “foreseeable future” to refer to the time over which identified threats are likely to impact the biological status of the species. The duration of the “foreseeable future” in any circumstance is inherently fact-specific and depends on the particular kinds of threats, the life-history characteristics, and the specific habitat requirements for the species under consideration. The existence of a threat to a species and the species' response to that threat are not, in general, equally predictable or foreseeable. Hence, in some cases, the ability to foresee a threat to a species is greater than the ability to foresee the species' exact response, or the timeframe of such a response, to that threat
, and the specific habitat requirements for the species under consideration. The existence of a threat to a species and the species' response to that threat are not, in general, equally predictable or foreseeable. Hence, in some cases, the ability to foresee a threat to a species is greater than the ability to foresee the species' exact response, or the timeframe of such a response, to that threat. For purposes of making these 12-month findings, the relevant consideration is whether the species' population response ( i.e., abundance, productivity, spatial distribution, diversity) is foreseeable, not merely whether the emergence of a threat is foreseeable. The foreseeable future extends only as far as we are able to reliably predict the species' population response to a particular threat. We consider the extent to which we can foresee the species' response to each threat.
“Significant Portion of its Range”
NMFS and FWS recently published a final policy to clarify the interpretation of the phrase “significant portion of the range” in the ESA definitions of “threatened species” and “endangered species” (79 FR 37577; July 1, 2014) (Final Policy). The Final Policy reads:
Consequences of a species being endangered or threatened throughout a significant portion of its range: The phrase “significant portion of its range” in the Act's definitions of “endangered species” and “threatened species” provides an independent basis for listing. Thus, there are two situations (or factual bases) under which a species would qualify for listing: A species may be endangered or threatened throughout all of its range or a species may be endangered or threatened throughout only a significant portion of its range.
If a species is found to be endangered or threatened throughout only a significant portion of its range, the entire species is listed as endangered or threatened, respectively, and the Act's protections apply to all individuals of the species wherever found
d or threatened throughout all of its range or a species may be endangered or threatened throughout only a significant portion of its range.
If a species is found to be endangered or threatened throughout only a significant portion of its range, the entire species is listed as endangered or threatened, respectively, and the Act's protections apply to all individuals of the species wherever found.
Significant: A portion of the range of a species is “significant” if the species is not currently endangered or threatened throughout its range, but the portion's contribution to the viability of the species is so important that, without the members in that portion, the species would be in danger of extinction, or likely to become so in the foreseeable future, throughout all of its range.
Range: The range of a species is considered to be the general geographical area within which that species can be found at the time FWS or NMFS makes any particular status determination. This range includes those areas used throughout all or part of the species' life cycle, even if they are not used regularly ( e.g., seasonal habitats). Lost historical range is relevant to the analysis of the status of the species, but it cannot constitute a significant portion of a species' range.
Reconciling SPR with DPS authority: If the species is endangered or threatened throughout a significant portion of its range, and the population in that significant portion is a valid DPS, we will list the DPS rather than the entire taxonomic species or subspecies.
The Final Policy explains that it is necessary to fully evaluate a portion for potential listing under the “significant portion of its range” authority only if substantial information indicates that the members of the species in a particular area are likely both to meet the test for biological significance and to be currently endangered or threatened in that area
taxonomic species or subspecies.
The Final Policy explains that it is necessary to fully evaluate a portion for potential listing under the “significant portion of its range” authority only if substantial information indicates that the members of the species in a particular area are likely both to meet the test for biological significance and to be currently endangered or threatened in that area. Making this preliminary determination triggers a need for further review, but does not prejudge whether the portion actually meets these standards such that the species should be listed:
To identify only those portions that warrant further consideration, we will determine whether there is substantial information indicating that (1) the portions may be significant and (2) the species may be in danger of extinction in those portions or likely to become so within the foreseeable future. We emphasize that answering these questions in the affirmative is not a determination that the species is endangered or threatened throughout a significant portion of its range—rather, it is a step in determining whether a more detailed analysis of the issue is required.
79 FR 37586. Thus, the preliminary determination that a portion may be both significant and endangered or threatened merely requires NMFS to engage in a more detailed analysis to determine whether the standards are actually met. Id. at 37587. Unless both are met, listing is not warranted. The Final Policy explains that, depending on the particular facts of each situation, NMFS may find it is more efficient to address the significance issue first, but in other cases it will make more sense to examine the status of the species in the potentially significant portions first. Whichever question is asked first, an affirmative answer is required to proceed to the second question. Id
nted. The Final Policy explains that, depending on the particular facts of each situation, NMFS may find it is more efficient to address the significance issue first, but in other cases it will make more sense to examine the status of the species in the potentially significant portions first. Whichever question is asked first, an affirmative answer is required to proceed to the second question. Id. (“[I]f we determine that a portion of the range is not “significant,” we will not need to determine whether the species is endangered or threatened there; if we determine that the species is not endangered or threatened in a portion of its range, we will not need to determine if that portion was “significant.”). Thus, if the answer to the first question is negative—whether in regard to the significance question or the status question—then the analysis concludes and listing is not warranted.
Background
The humpback whale ( Megaptera novaeangliae ) was listed as endangered in 1970 under the Endangered Species Conservation Act of 1969, the precursor to the ESA. When the ESA was enacted in 1973, the humpback whale was transferred to the List of Endangered and Threatened Wildlife and Plants, retaining endangered status, and, because of its endangered ESA status, was considered “depleted” under the Marine Mammal Protection Act (MMPA). NMFS issued a recovery plan for the humpback whale in 1991, and its long-term numerical goal was to increase humpback whale populations to at least 60 percent of the number existing before commercial exploitation or of current environmental carrying capacity. The recovery team recognized that those levels could not then be determined, so in the meantime, the interim goal of the recovery plan was to double the population size of extant populations within the next 20 years ( http://www.nmfs.noaa.gov/pr/pdfs/recovery/whale_humpback.pdf ). In fact, the historical size of humpback whale populations continues to be uncertain (Ruegg et al., 2013, and references therein; Bettridge et al., 2015)
hose levels could not then be determined, so in the meantime, the interim goal of the recovery plan was to double the population size of extant populations within the next 20 years ( http://www.nmfs.noaa.gov/pr/pdfs/recovery/whale_humpback.pdf ). In fact, the historical size of humpback whale populations continues to be uncertain (Ruegg et al., 2013, and references therein; Bettridge et al., 2015).
The taxonomy, life history, and ecology of the humpback whale are thoroughly reviewed in Fleming and Jackson (2011) and summarized in the BRT's status review report (Bettridge et al., 2015; available at http://www.nmfs.noaa.gov/pr/species/statusreviews.htm ). The humpback whale is a large baleen whale of the
Its body coloration is primarily dark grey, but individuals have a variable amount of white on their pectoral fins, flukes, and belly. This variation is so distinctive that the pigmentation pattern on the undersides of their flukes is used to identify individual whales. Coloring of the ventral surface varies from white to marbled to fully black. Dorsal surfaces of humpback whale pectoral flippers are typically white in the North Atlantic and black in the North Pacific (Perrin et al., 2002), and the flippers are about one-third of the total body length. Similar to all baleen whales, body lengths differ between the sexes, with adult females being approximately 1-1.5m longer than males. The humpback whale reaches a maximum of 16-17 m, although lengths of 14-15 m are more typical. Adult body weights in excess of 40 tons make them one of the largest mammals on earth (Ohsumi, 1966).
With one exception, humpback whales are highly migratory, spending spring, summer, and fall feeding in temperate or high-latitude areas of the North Atlantic, North Pacific, and Southern Ocean and migrating to the tropics in winter to breed and calve. The Arabian Sea humpback whale population does not migrate extensively, remaining in tropical waters year-round (Baldwin, 2000; Minton et al., 2010b)
ith one exception, humpback whales are highly migratory, spending spring, summer, and fall feeding in temperate or high-latitude areas of the North Atlantic, North Pacific, and Southern Ocean and migrating to the tropics in winter to breed and calve. The Arabian Sea humpback whale population does not migrate extensively, remaining in tropical waters year-round (Baldwin, 2000; Minton et al., 2010b).
There are 14 known breeding grounds for humpback whales, and there may be other breeding grounds of unknown location. Whales using the unknown breeding grounds may be associated to some degree with whales from the known breeding grounds.
Whales from all known breeding grounds except the Arabian Sea migrate to summer feeding areas. Humpback whales have high site fidelity to both the winter breeding grounds and summer feeding grounds. Whales from a single breeding ground may migrate to different feeding grounds. In addition, feeding grounds may host whales from different breeding grounds. Because humpback whales can be individually identified through unique fluke patterns, researchers are able to match photos of whales on breeding grounds and feeding grounds, thereby tracing their migrations.
Although the patterns of migration and distribution are clear for many breeding groups, researchers have identified whales on some feeding grounds that have never been sighted in any of the known breeding grounds. Depending on the strength of the evidence, scientists may infer that an additional breeding population exists but that its breeding grounds are unknown. We explore this subject further in the “Distinct Population Segment Analysis, By Subspecies” section below.
Behavior
Humpback whales travel great distances during migration, the farthest migration of any mammal. The longest recorded migration between a breeding area and a feeding area was 5,160 miles (8,300 km). This trek from Costa Rica to Antarctica was completed by seven individuals, including a calf (Rasmussen et al., 2007)
the “Distinct Population Segment Analysis, By Subspecies” section below.
Behavior
Humpback whales travel great distances during migration, the farthest migration of any mammal. The longest recorded migration between a breeding area and a feeding area was 5,160 miles (8,300 km). This trek from Costa Rica to Antarctica was completed by seven individuals, including a calf (Rasmussen et al., 2007). One of the more closely studied routes has shown whales making the 3,000-mile (4,830 km) trip between Alaska and Hawaii in as little as 36 days (Allen and Angliss, 2010).
During summer and fall, humpback whales spend much of their time feeding and building fat stores for winter. In their low-latitude wintering grounds, humpback whales congregate and are believed to engage in mating and other social activities. Humpback whales are generally polygynous, with males exhibiting competitive behavior on wintering grounds (Tyack, 1981; Baker and Herman, 1984; Clapham, 1996). A complex behavioral repertoire exhibited in these areas can include aggressive and antagonistic behavior, such as chasing, vocal and bubble displays, horizontal tail thrashing, and rear body thrashing. Males within these groups also make physical contact, striking or surfacing on top of one another.
Also on wintering grounds, males sing complex songs that can last up to 20 minutes and may be heard up to 20 miles (30 km) away (Clapham and Mattila, 1990; Cato, 1991). A male may sing for hours, repeating the song numerous times. All males in a population sing the same song, but that song continually evolves over time (Darling and Sousa-Lima, 2005). Humpback whale singing has been studied for decades, but its function remains in dispute.
Humpback whales are a favorite of whale watchers, as the species frequently performs aerial displays, including breaching, lobtailing, and flipper slapping, the purposes of which are not well understood
opulation sing the same song, but that song continually evolves over time (Darling and Sousa-Lima, 2005). Humpback whale singing has been studied for decades, but its function remains in dispute.
Humpback whales are a favorite of whale watchers, as the species frequently performs aerial displays, including breaching, lobtailing, and flipper slapping, the purposes of which are not well understood. Diving behavior varies by season, with average lengths of dives ranging from <5 minutes in summer to 10-15 minutes (and sometimes more than 30 minutes) in winter months (Clapham and Mead, 1999). Typically, humpback whale groups are small (e.g ., <10 individuals, but can vary depending on social context and season), and associations between individuals do not last long, with the exception of the mother/calf pairs (Clapham and Mead, 1999).
Feeding
Humpback whales have a diverse diet that varies slightly across feeding areas. The species is known to feed on both small schooling fish and on euphausiids (krill). Known prey organisms include species representing Clupea (herring), Scomber (mackerel), Ammodytes (sand lance), Sardinops (sardine), Engraulis (anchovy), Mallotus (capelin), and krills such as Euphausia, Thysanoessa, and Meganyctiphanes (Baker, 1985; Geraci et al., 1989; Clapham et al., 1997). Humpback whales also exhibit flexible feeding strategies, sometimes foraging alone and sometimes cooperatively (Clapham, 1993). During the winter, humpback whales subsist on stored fat and likely feed little or not at all.
In the Northern Hemisphere, feeding behavior is varied and frequently features novel capture methods involving the creation of bubble structures to trap and corral fish; bubble nets, clouds, and curtains can be observed when humpback whales are feeding on schooling fish (Hain et al., 1982)
pham, 1993). During the winter, humpback whales subsist on stored fat and likely feed little or not at all.
In the Northern Hemisphere, feeding behavior is varied and frequently features novel capture methods involving the creation of bubble structures to trap and corral fish; bubble nets, clouds, and curtains can be observed when humpback whales are feeding on schooling fish (Hain et al., 1982). Lobtailing and repeated underwater `looping' movements (referred to as kick feeding) have also been observed during surface feeding events, and it may be that certain feeding behaviors are spread through the population by cultural transmission (Weinrich et al., 1992; Friedlaender et al., 2006). On Stellwagen Bank, in the Gulf of Maine, repeated side rolls have been recorded when whales were near the bottom, which likely serves to startle prey out of the substrate for better foraging (Friedlaender et al., 2009). In many locations, feeding in the water column can vary with time of day, with whales bottom feeding at night and surface feeding near dawn (Friedlaender et al., 2009).
Humpback whales are `gulp' or `lunge' feeders, capturing large mouthfuls of prey during feeding rather than continuously filtering food, as may be observed in some other large baleen whales (Ingebrigtsen, 1929). In the Southern Hemisphere, only one style of foraging (`lunge' feeding) has been reported. When lunge feeding, whales advance on prey with their mouths wide open, then close their mouths around the prey and trap them by forcing engulfed water out past the baleen Euphausia superba ) (Matthews, 1937; Mackintosh, 1965; Kawamura, 1994).
Stomach content analysis from hunted whales taken in sub-tropical waters and on migratory routes indicated that stomachs were nearly always empty (Chittleborough, 1965a). Infrequent sightings of feeding activity and stomach content data suggest that some individuals may feed opportunistically during the southward migration toward Antarctic waters (Matthews, 1932; Dawbin, 1956; Kawamura, 1980)
).
Stomach content analysis from hunted whales taken in sub-tropical waters and on migratory routes indicated that stomachs were nearly always empty (Chittleborough, 1965a). Infrequent sightings of feeding activity and stomach content data suggest that some individuals may feed opportunistically during the southward migration toward Antarctic waters (Matthews, 1932; Dawbin, 1956; Kawamura, 1980).
In the Southern Ocean, Antarctic krill tend to be most highly concentrated around marginal sea ice zones, where they feed on sea ice algae. As a result, Southern Hemisphere humpback whale distribution is linked to regions of marginal sea ice (Friedlaender et al., 2006) and zones of high euphausiid density (Murase et al., 2002), with foraging mainly concentrated in the upper 100m of the water column (Dolphin, 1987; Friedlaender et al., 2006). There is evidence of a positive relationship between prey density and humpback whale abundance (Friedlaender et al., 2006).
Reproduction
The mating system of humpback whales is generally thought to be male-dominance polygyny, also described as a `floating lek' (Clapham, 1996). In this system, multiple males compete for individual females and exhibit competitive behavior. Humpback whale song is a long, complex vocalization (Payne and McVay, 1971) produced by males on the winter breeding grounds, and also less commonly during migration (Clapham and Mattila, 1990; Cato, 1991) and on feeding grounds (Clark and Clapham, 2004b). The exact function has not been determined, but behavioral studies suggest that song is used to advertise for females, and/or to establish dominance among males (Tyack, 1981; Darling and Bérubé, 2001; Darling et al., 2006). It is widely believed that, while occasional mating may occur on feeding grounds or on migration, the great majority of mating and conceptions take place in winter breeding areas (Clapham, 1996; Clark and Clapham, 2004a)
but behavioral studies suggest that song is used to advertise for females, and/or to establish dominance among males (Tyack, 1981; Darling and Bérubé, 2001; Darling et al., 2006). It is widely believed that, while occasional mating may occur on feeding grounds or on migration, the great majority of mating and conceptions take place in winter breeding areas (Clapham, 1996; Clark and Clapham, 2004a). Breeding in the Northern and Southern Hemisphere populations is out of phase by approximately 6 months, corresponding to their respective winter periods.
Sexual maturity of humpback whales in the Northern Hemisphere occurs at approximately 5-11 years of age, and appears to vary both within and among populations (Clapham, 1992; Gabriele et al., 2007b; Robbins, 2007). Average age of sexual maturity in the Southern Hemisphere is estimated to be 9-11 years. In the Northern Hemisphere, calving intervals are between 1 and 5 years, though 2-3 years appears to be most common (Wiley and Clapham, 1993; Steiger and Calambokidis, 2000). Estimated mean calving rates are between 0.38 and 0.50 calves per mature female per year (Clapham and Mayo, 1990; Straley et al., 1994; Steiger and Calambokidis, 2000) and reproduction is annually variable (Robbins, 2007). In the Southern Hemisphere, most information on humpback whale population characteristics and life history was obtained during the whaling period. Post-partum ovulation is reasonably common (Chittleborough, 1965a) and inter-birth intervals of a single year have occasionally been recorded. This may be a consequence of early calf mortality; the associated survival rates for annually born calves are unknown in the Southern Hemisphere.
Humpback whale gestation is 11-12 months and calves are born in tropical waters (Matthews, 1937). Lactation lasts from 10.5-11 months (Chittleborough, 1965a), weaning begins to occur at about age 6 months, and calves attain maternal independence around the end of their first year (Clapham and Mayo, 1990)
e associated survival rates for annually born calves are unknown in the Southern Hemisphere.
Humpback whale gestation is 11-12 months and calves are born in tropical waters (Matthews, 1937). Lactation lasts from 10.5-11 months (Chittleborough, 1965a), weaning begins to occur at about age 6 months, and calves attain maternal independence around the end of their first year (Clapham and Mayo, 1990). Humpback whales exhibit maternally directed fidelity to specific feeding regions (Martin et al., 1984; Baker et al., 1990).
The average generation time for humpback whales (the average age of all reproductively active females at carrying capacity) is estimated at 21.5 years (Taylor et al., 2007). Empirically estimated annual rates of population increase range from a low of 0 to 4 percent to a maximum of 12.5 percent for different times and areas throughout the range (Baker et al., 1992; Barlow and Clapham, 1997; Steiger and Calambokidis, 2000; Clapham et al., 2003a); however, Zerbini et al. (2010) concluded that any rate above 11.8 percent per year is biologically implausible for this species.
Natural Mortality
Annual adult mortality rates have been estimated to be 0.040 (standard error (SE) = 0.008) (Barlow and Clapham, 1997) in the Gulf of Maine and 0.037 (95 percent confidence interval (CI) 0.022-0.056) (Mizroch et al., 2004) in the Hawaiian Islands populations. In the Southern Hemisphere, estimates of annual adult survival rates have been made using photo-identification studies in Hervey Bay, east Australia (1987-2006), and range between 0.87 and 1.00 (Chaloupka et al., 1999).
Robbins (2007) estimated calf (0-1 year old) survival for humpback whales in the Gulf of Maine at 0.664 (95 percent CI: 0.517-0.784), which is low compared to other areas. Barlow and Clapham (1997) estimated a theoretical calf mortality rate of 0.125 on the Gulf of Maine feeding ground
on studies in Hervey Bay, east Australia (1987-2006), and range between 0.87 and 1.00 (Chaloupka et al., 1999).
Robbins (2007) estimated calf (0-1 year old) survival for humpback whales in the Gulf of Maine at 0.664 (95 percent CI: 0.517-0.784), which is low compared to other areas. Barlow and Clapham (1997) estimated a theoretical calf mortality rate of 0.125 on the Gulf of Maine feeding ground. Using associations of calves with identified mothers on North Pacific breeding and feeding grounds, Gabriele (2001) estimated mortality of juveniles at 6 months of age to be 0.182 (95 percent CI: 0.023-0.518). Survival of calves (6-12 months) and juveniles (1-5 years) has not been described in detail for the Southern Hemisphere. Killer whales are likely the most common natural predators of humpback whales.
Status Review Report
The BRT's status review report compiled the best available scientific and commercial information on: (1) Population structure of humpback whales within the North Pacific, North Atlantic, and Southern Oceans, used to determine whether any populations within these ocean basins meet the DPS policy criteria; (2) the abundance and trend information for each DPS; (3) those ESA section 4(a)(1) factors currently affecting the status of these DPSs; (4) ongoing conservation efforts affecting the status of these DPSs; and (5) the extinction risk of each DPS. See the status review report for further information on the biology and ecology of the humpback whale (Bettridge et al., 2015).
Humpback Whale Subspecies
The BRT reviewed the best scientific and commercial data available on the humpback whale's taxonomy and concluded that there are likely three unrecognized subspecies of humpback whale: North Pacific, North Atlantic, and Southern Hemisphere. In reaching this conclusion, the BRT considered available life history, morphological, and genetic information.
Humpback whales routinely make extensive migrations between breeding and feeding areas within an ocean basin
ble on the humpback whale's taxonomy and concluded that there are likely three unrecognized subspecies of humpback whale: North Pacific, North Atlantic, and Southern Hemisphere. In reaching this conclusion, the BRT considered available life history, morphological, and genetic information.
Humpback whales routinely make extensive migrations between breeding and feeding areas within an ocean basin. Despite this potential for long distance dispersal, there is considerable evidence that dispersal or interbreeding of individuals from different major ocean basins is extremely rare and that whales from the major ocean basins are differentiated by a number of characteristics.
Reproductive Seasonality : Humpback whales breed and calve in July-
Behavior: The most obvious behavioral difference is that migrations to and from high latitudes are in opposite times of the calendar year for Southern Hemisphere and most Northern Hemisphere populations, following the difference in reproductive seasonality. A Northern Hemisphere exception to this migration pattern is found in the Arabian Sea where a non-migratory population is found. Although these behavioral differences could be learned, they could also be innate, genetically determined traits. Seasonality in singing and other mating behaviors also follows the differences in reproductive seasonality.
Color patterns: Humpback whales in the Southern Hemisphere tend to have much more white pigmentation on their bodies which is especially noticeable laterally (Matthews, 1937; Chittleborough, 1965b). This has been noted in eastern and western Australia, the Coral Sea, and Oceania, but might not be characteristic of all Southern Hemisphere populations. Rosenbaum et al. (1995) ranked ventral fluke coloration patterns from one (nearly all white) to five (nearly all black) and compared whales from several breeding areas
ch is especially noticeable laterally (Matthews, 1937; Chittleborough, 1965b). This has been noted in eastern and western Australia, the Coral Sea, and Oceania, but might not be characteristic of all Southern Hemisphere populations. Rosenbaum et al. (1995) ranked ventral fluke coloration patterns from one (nearly all white) to five (nearly all black) and compared whales from several breeding areas. He found that over 80 percent of humpback whales in eastern and western Australia were in Category 1, and that less than 10 percent of whales in three breeding areas in the North Pacific were ranked in that category. Only 36 percent of Southern Hemisphere whales in Colombia were classified in Category 1, but Colombian whales were still, on average, whiter than North Pacific whales. A higher frequency of flippers with white dorsal pigmentations is found in the North Atlantic compared to the North Pacific (Clapham, 2009).
Genetics: Baker and Medrano-Gonzalez (2002) reviewed the worldwide distribution of mtDNA haplotypes. 1 They found three major clades (groups consisting of an ancestor and all its descendants) with significant differences among major ocean basins, though there were no completely fixed differences among these areas. The North Pacific included only the AE and CD clades, the North Atlantic included only the CD and IJ clades, and the Southern Oceans included all three. In a more recent comparison, Jackson et al. (2014) found no shared haplotypes between the North Pacific and North Atlantic. Based on patterns of mtDNA variation, Rosenbaum et al. (2009b) estimated an average migration rate of less than one per generation between the Arabian Sea and neighboring populations in the southern Indian Ocean, and Jackson et al. (2014) also estimated generally <1 migrant per generation among the North Pacific, North Atlantic and Southern Hemisphere populations. Ruegg et al. (2013) also found a high degree of genetic differentiation between samples from the North Atlantic and the Southern Hemisphere
than one per generation between the Arabian Sea and neighboring populations in the southern Indian Ocean, and Jackson et al. (2014) also estimated generally <1 migrant per generation among the North Pacific, North Atlantic and Southern Hemisphere populations. Ruegg et al. (2013) also found a high degree of genetic differentiation between samples from the North Atlantic and the Southern Hemisphere.
1 A mtDNA haplotype is a group of genes, or alleles, that is maternally inherited; genetic differentiation is generally based on allele frequency differences between populations, which are measured by F ST or related statistics; F ST is a measure of the genetic distance between populations, or difference in the allele frequency between two populations.
Subspecies Discussion and Conclusions
The BRT considered the possibility that humpback whales from different ocean basins might reasonably be considered to belong to different subspecies. Sub-specific taxonomy is relevant to the identification of DPSs because, under the 1996 DPS policy, the discreteness and significance of a potential DPS is evaluated with reference to the taxon (species or subspecies) to which it belongs. In some cases previous BRTs have determined that sub-specific taxonomy has a large influence on DPS structure ( e.g., southern resident killer whales—Krahn et al., 2004a)), while in other cases sub-specific taxonomy has not been relevant ( e.g., steelhead trout DPS—Busby et al., 1996).
Rice (1998) reviewed previous subspecies designations for humpback whales. Tomilin (1946) named a Southern Hemisphere subspecies ( M. n. lalandii ) based on body length, but this length difference was not substantiated in subsequent studies. The populations around Australia and New Zealand were described as another subspecies ( M. n. novazelandiae ) based on color patterns and length (Ivashin, 1958)
ce (1998) reviewed previous subspecies designations for humpback whales. Tomilin (1946) named a Southern Hemisphere subspecies ( M. n. lalandii ) based on body length, but this length difference was not substantiated in subsequent studies. The populations around Australia and New Zealand were described as another subspecies ( M. n. novazelandiae ) based on color patterns and length (Ivashin, 1958). Rice (1998) noted that the statistical ability to classify these proposed subspecies is “not quite as high as is customarily required for division into subspecies” and that genetic analyses using restriction-fragment length polymorphisms is not congruent with the proposed regional division. Rice (1998) therefore recommended that Megaptera novaeangliae be considered monotypic. As was summarized above, however, since 1998, additional information has accumulated on the genetic distinctiveness of different geographic populations of humpback whales, and some new subspecies have been proposed (Jackson et al., 2014).
One criterion for separation of subspecies is the ability to differentiate 75 percent of individuals found in different geographic regions (Reeves et al., 2004). Based on this criterion, differences in the calendar timing of mating and reproduction could be used to distinguish close to 100 percent of Northern Hemisphere from Southern Hemisphere individuals, but it is not known if this is genetically determined. Based on mtDNA haplotypes that have been identified to date, haplotype could be used to distinguish 100 percent of North Pacific from North Atlantic individuals, but some haplotypes from both ocean basins are shared with the Southern Ocean. Ventral fluke color patterns can be used to correctly differentiate >80 percent of whales in eastern and western Australia from the whales in the North Pacific (Rosenbaum et al., 1995).
The BRT also considered the advice of the Committee on Taxonomy of the Society for Marine Mammalogy (SMM)
North Atlantic individuals, but some haplotypes from both ocean basins are shared with the Southern Ocean. Ventral fluke color patterns can be used to correctly differentiate >80 percent of whales in eastern and western Australia from the whales in the North Pacific (Rosenbaum et al., 1995).
The BRT also considered the advice of the Committee on Taxonomy of the Society for Marine Mammalogy (SMM). The BRT asked the Committee: “Are humpback whales ( Megaptera novaeangliae ) that feed in the North Atlantic, North Pacific, Southern Oceans and Arabian Sea likely to belong to different sub-species?” The SMM was asked only for its scientific opinion on the likelihood of the existence of humpback whale subspecies and was not asked to comment on the relevance of their opinion to the identification of DPSs for humpback whales. The SMM chairman summarized responses from members of the SMM:
The balance of opinion in the SMM Committee on Taxonomy is that given the evidence on genetics, morphology, distribution and behavior, if a taxonomic revision of the humpback whale were undertaken, it is likely that the North Atlantic, North Pacific and Southern Hemisphere populations would be accorded subspecific status. Whether the Arabian Sea population would merit recognition as a subspecies separate from the Southern Hemisphere whales, with which it is most closely related genetically, is less certain. However, it is clearly geographically isolated and genetically differentiated
rtaken, it is likely that the North Atlantic, North Pacific and Southern Hemisphere populations would be accorded subspecific status. Whether the Arabian Sea population would merit recognition as a subspecies separate from the Southern Hemisphere whales, with which it is most closely related genetically, is less certain. However, it is clearly geographically isolated and genetically differentiated.
Using its structured decision making process (whereby each BRT member distributed 100 likelihood points among different scenarios), the BRT considered the likelihood of a single global species with no subspecies scenario, a three-subspecies scenario (North Atlantic, North Pacific, and Southern
In October 2014, after the BRT report was completed, the SMM updated its species and subspecies list to recognize the North Atlantic, North Pacific, and Southern Hemisphere humpback whale populations as subspecies: Megaptera novaeangliae kuzira (North Pacific), M. n. novaeangliae (North Atlantic) and M. n. australis (Southern Hemisphere) ( http://www.marinemammalscience.org/index.php?option=com_content&view=article&id=758&Itemid=340 ). This update was based on mtDNA and DNA relationships and distribution, as described in Jackson et al. (2014). We therefore consider whether the various humpback whale population segments identified by the BRT satisfy the DPS criteria of discreteness and significance relative to the subspecies to which they each belong: North Atlantic, North Pacific, and Southern Hemisphere subspecies.
Distinct Population Segment Analysis, By Subspecies
North Atlantic
Overview
In the Northern Hemisphere, humpback whales summer in the biologically productive, northern latitudes and travel south to warmer waters in winter to mate and calve. Migratory routes and migratory behavior are likely to be maternally directed (Martin et al., 1984; Baker et al., 1990)
Southern Hemisphere subspecies.
Distinct Population Segment Analysis, By Subspecies
North Atlantic
Overview
In the Northern Hemisphere, humpback whales summer in the biologically productive, northern latitudes and travel south to warmer waters in winter to mate and calve. Migratory routes and migratory behavior are likely to be maternally directed (Martin et al., 1984; Baker et al., 1990). Feeding areas are often near or over the continental shelf and are associated with cooler temperatures and oceanographic or topographic features that serve to aggregate prey (Moore et al., 2002; Zerbini et al., 2006a).
Primary humpback whale feeding areas in the North Atlantic Ocean range from 42° to 78°N and include waters around Iceland, Norway, and the Barents Sea in the central and eastern North Atlantic Ocean, and western Greenland, Newfoundland, Labrador, the Gulf of St. Lawrence and the Gulf of Maine in the western North Atlantic Ocean. Known breeding areas occur in the West Indies and, to a much lesser extent, around the Cape Verde Islands (Katona and Beard, 1990; Clapham, 1993; Palsbøll et al., 1997). A relatively small proportion of whales in the North Atlantic Ocean feed in U.S. waters. The predominant breeding and calving area lies in the territorial sea of the Dominican Republic, although whales are also found scattered throughout the rest of the Antilles and coastal waters of Venezuela. The Silver/Navidad/Mouchoir Bank complex hosts the largest single breeding aggregation of humpback whales in the West Indies.
Recently, a few humpback whales have also been found in the Mediterranean Sea but little is known about humpback whale use of this region and there is no evidence of a large humpback whale presence there, either currently or in historical times (Frantzis et al., 2004). There are also sporadic sightings of humpback whales in a wide range of places, including waters offshore from the mid-Atlantic and Southeast United States, in the Gulf of Mexico, and in the waters around Ireland
little is known about humpback whale use of this region and there is no evidence of a large humpback whale presence there, either currently or in historical times (Frantzis et al., 2004). There are also sporadic sightings of humpback whales in a wide range of places, including waters offshore from the mid-Atlantic and Southeast United States, in the Gulf of Mexico, and in the waters around Ireland. Bermuda is a known mid-ocean stopover point for humpback whales on their northbound migration (Stone et al., 1987).
Discreteness
Genetic studies have identified 25 humpback whale haplotypes in the western North Atlantic, 12 haplotypes in eastern North Atlantic samples, and 19 haplotypes in whales that feed during the summer in the Gulf of Maine (Palsbøll et al., 1995; Larsen, 1996a; Rosenbaum et al., 2002). Humpback whales in the North Atlantic Ocean appear to have higher haplotype diversity than humpback whales in the North Pacific Ocean (Baker and Medrano-González, 2002). Haplotype diversity is lowest in populations around Norway and Iceland and higher around the northwestern feeding areas off Greenland, Gulf of St. Lawrence and Gulf of Maine (Baker and Medrano-González, 2002). Observed nucleotide diversity is also higher in the North Atlantic than in the North Pacific (Baker and Medrano-González, 2002).
Whales that breed in the West Indies and Cape Verde Islands co-mingle in North Atlantic feeding areas. Palsboll et al. (1995) and Valsecchi et al. (1997) found significant (F ST = ~0.04) levels of mtDNA and nuclear genetic variation among North Atlantic feeding areas, suggesting there are genetically distinct breeding areas (there are no published genetic studies directly comparing whales in the West Indies breeding areas with whales in the Cape Verde Islands breeding areas)
Atlantic feeding areas. Palsboll et al. (1995) and Valsecchi et al. (1997) found significant (F ST = ~0.04) levels of mtDNA and nuclear genetic variation among North Atlantic feeding areas, suggesting there are genetically distinct breeding areas (there are no published genetic studies directly comparing whales in the West Indies breeding areas with whales in the Cape Verde Islands breeding areas). Photo-ID and genetic matching data suggest no evidence for substructure within the West Indies breeding population (reviewed by Fleming and Jackson (2011)), so this differentiation likely is due to genetic divergence between the West Indies and another North Atlantic breeding population, likely associated with the Cape Verde Islands or possibly other areas in the Northeastern Atlantic.
Most of the humpback whales on the western North Atlantic feeding grounds (Gulf of Maine, Gulf of St. Lawrence, West Greenland, and eastern Canada) come from the well-studied West Indies breeding ground (approximately 90 percent) (Clapham et al., 1993; Mattila et al., 2001). Some of the whales from the Iceland and Norway feeding grounds also come from the West Indies breeding grounds, but genetic evidence suggests that most whales from the Iceland and Norway feeding grounds migrate from some other breeding ground. The location of possible breeding grounds of these whales is not well understood, but Clapham et al. (1993) suggest it may be in the eastern tropical Atlantic Ocean. Sighting histories of the Cape Verde Islands whales link them to feeding grounds in the waters off Iceland or Norway (Katona and Beard, 1990; Jann et al., 2003), and the Cape Verde Islands is the only candidate breeding ground from historical whaling records. However, current studies show only a small number of whales in the Cape Verde Islands—far fewer than the non-West Indies whales known to exist in the northeastern Atlantic
Verde Islands whales link them to feeding grounds in the waters off Iceland or Norway (Katona and Beard, 1990; Jann et al., 2003), and the Cape Verde Islands is the only candidate breeding ground from historical whaling records. However, current studies show only a small number of whales in the Cape Verde Islands—far fewer than the non-West Indies whales known to exist in the northeastern Atlantic. The Cape Verde Islands may therefore be part of a larger breeding area, or there may be a third separate breeding area that is as yet undiscovered (Charif et al., 2001; Reeves et al., 2002). The possibility of a third breeding area unassociated with the Cape Verde Islands is supported by nuclear DNA, as there is a significant degree of heterogeneity in nuclear DNA among populations in the western, central (Iceland) and eastern (Norway) North Atlantic feeding grounds (Larsen, 1996b).
The BRT concluded there are two populations of humpback whales in the North Atlantic Ocean meeting the discreteness criteria under the DPS policy—one with breeding grounds in the West Indies and another with breeding grounds near Cape Verde Islands and a possible associated breeding area, likely off Northwest Africa. In particular, whales from the West Indies and the Cape Verde Islands breeding grounds are discrete based on: (1) No photographic matches between individuals using the West Indies and Cape Verde Islands areas (acknowledging that there is a large sample size for the West Indies breeding grounds and a small sample size for the Cape Verde Islands breeding grounds); (2) occupation of both breeding grounds at the same time; (3) evidence from 19th century whaling data of a historically larger population at the Cape Verde Islands than exists today; and (4) genetic
Significance
The West Indies breeding ground includes the Atlantic margin of the Antilles from Cuba to northern Venezuela, with the Silver/Navidad/Mouchoir Bank complex comprising a major breeding ground
cupation of both breeding grounds at the same time; (3) evidence from 19th century whaling data of a historically larger population at the Cape Verde Islands than exists today; and (4) genetic
Significance
The West Indies breeding ground includes the Atlantic margin of the Antilles from Cuba to northern Venezuela, with the Silver/Navidad/Mouchoir Bank complex comprising a major breeding ground. Whales from this breeding ground have a feeding range that primarily includes the Gulf of Maine, eastern Canada, and western Greenland. While many West Indies whales also use feeding grounds in the central North Atlantic (Iceland) and eastern North Atlantic (Norway), many whales from these feeding areas appear to winter in another location.
The BRT concluded this discrete group of whales is significant to the North Atlantic subspecies due to the significant gap in the breeding range that would occur if it were extirpated. Loss of the West Indies population would result in the loss of humpback whales from all of the western North Atlantic breeding grounds (Caribbean/West Indies) and feeding grounds (United States, Canada, Greenland).
The Cape Verde Islands/Northwest Africa breeding grounds include waters surrounding the Cape Verde Islands as well as an undetermined breeding area in the eastern tropical Atlantic, which may be more geographically diffuse than the West Indies breeding ground. The population of whales breeding in Cape Verde Islands plus this unknown area likely represents the remnants of a historically larger population breeding around Cape Verde Islands and Northwest Africa (Reeves et al., 2002). There is no known overlap in breeding range with North Atlantic humpback whales that breed in the West Indies. As noted above, the BRT determined the population was discrete from the West Indies population based upon genetic evidence that suggests a second breeding ground occupied by whales that feed primarily off Norway and Iceland
nd Cape Verde Islands and Northwest Africa (Reeves et al., 2002). There is no known overlap in breeding range with North Atlantic humpback whales that breed in the West Indies. As noted above, the BRT determined the population was discrete from the West Indies population based upon genetic evidence that suggests a second breeding ground occupied by whales that feed primarily off Norway and Iceland. It also determined that this population was significant to the North Atlantic subspecies because of the gap that would exist in the breeding range if it were extirpated.
We agree with the BRT and we therefore identify two DPSs of the North Atlantic humpback whale subspecies: (1) West Indies DPS; and (2) Cape Verde Islands/Northwest Africa DPS.
North Pacific
Overview
Humpback whales in the North Pacific migrate seasonally from northern latitude feeding areas in summer to low-latitude breeding areas in winter. Feeding areas are dispersed across the Pacific Rim from California, United States, to Hokkaido, Japan. Within these regions, humpback whales have been observed to spend the majority of their time feeding in coastal waters. Breeding areas in the North Pacific are more geographically separated than the feeding areas and include: (1) Regions offshore of mainland Central America; (2) mainland, Baja Peninsula and the Revillagigedos Islands, Mexico; (3) Hawaii; and (4) Asia including Ogasawara and Okinawa Islands and the Philippines. About half of the humpback whales in the North Pacific Ocean breed and calve in the U.S. waters off Hawaii; more than half of North Pacific Ocean humpback whales feed in U.S. waters.
Humpback whales in the North Pacific rarely move between these breeding regions. Strong fidelity to both feeding and breeding sites has been observed, but movements between feeding and breeding areas are complex and varied (Calambokidis et al., 2008). An overall pattern of migration has recently emerged
waters off Hawaii; more than half of North Pacific Ocean humpback whales feed in U.S. waters.
Humpback whales in the North Pacific rarely move between these breeding regions. Strong fidelity to both feeding and breeding sites has been observed, but movements between feeding and breeding areas are complex and varied (Calambokidis et al., 2008). An overall pattern of migration has recently emerged. Asia and Mexico/Central America are the dominant breeding areas for humpback whales that migrate to feeding areas in lower latitudes and more coastal areas on each side of the Pacific Ocean, such as California and Russia. The Revillagigedo Archipelago and Hawaiian Islands are the primary winter migratory destinations for humpback whales that feed in the more central and higher latitude areas (Calambokidis et al., 2008). However, there are exceptions to this pattern, and it seems that complex population structure and strong site fidelity coexist with lesser known, but potentially high, levels of plasticity in the movements of humpback whales (Salden et al., 1999).
Discreteness
Baker et al. (2013) recently analyzed genetic variation in a large (n = 2,193) sample of whales from 8 breeding and 10 feeding regions within the North Pacific. The 8 possible breeding regions included the Philippines, Okinawa, Ogasawara, Hawaii, Revillagigedo, Baja California, the Mexican mainland coast, and Central America. In addition, results from Calambokidis et al. (2008) indicate the existence of at least one additional breeding area whose location has not been identified. Overall, the level of genetic divergence among breeding areas at the mtDNA control region was substantial (F ST = 0.093). Pairwise estimates of divergence among breeding areas ranged from none (F ST = ~0.000; Philippines vs Okinawa) to very high (F ST > 0.2 for Hawaii versus Okinawa and Philippines, and Hawaii versus Central America)
additional breeding area whose location has not been identified. Overall, the level of genetic divergence among breeding areas at the mtDNA control region was substantial (F ST = 0.093). Pairwise estimates of divergence among breeding areas ranged from none (F ST = ~0.000; Philippines vs Okinawa) to very high (F ST > 0.2 for Hawaii versus Okinawa and Philippines, and Hawaii versus Central America). In addition to little divergence between Okinawa and the Philippines, the three Mexican areas (mainland coast, Baja California, and Revillagigedos Islands) were not significantly differentiated. In contrast to the mtDNA variation, the breeding areas were less strongly (but still significantly) differentiated at 10 nuclear microsatellite loci (F ST = 0.006), suggesting the possibility of some male mediated gene flow among breeding areas. After application of an adjustment for diversity (Hedrick, 2005; Baker et al., 2013), the effect size increased to F' ST = 0.0128 and F' ST = 0.0214 for feeding and breeding grounds, respectively. Of these nine areas, two are likely migratory routes to other locations and might therefore not be primary breeding grounds: the waters off Baja California and the Ogasawara Islands.
Similarly, some humpback whales migrating to the Okinawa Islands pass by the Ogasawara Islands, and the Ogasawara Islands are also thought likely to be along the migration route to the unidentified breeding area that was described in Calambokidis et al. (2008). Because of the existence of an unidentified breeding area, the population structure of the western North Pacific populations proved more challenging. Humpback whales in Okinawa were not significantly different in either mtDNA or nDNA from whales in the Philippines (Baker et al., 2013). Mitochondrial DNA and nDNA markers from the pooled populations from Okinawa and the Philippines populations differ significantly from those of humpback whales in the Ogasawara Islands and all other populations (Baker et al., 2013)
lations proved more challenging. Humpback whales in Okinawa were not significantly different in either mtDNA or nDNA from whales in the Philippines (Baker et al., 2013). Mitochondrial DNA and nDNA markers from the pooled populations from Okinawa and the Philippines populations differ significantly from those of humpback whales in the Ogasawara Islands and all other populations (Baker et al., 2013). However, given the likelihood that Ogasawara whales are only passing through en route to two or more migratory destinations, the BRT members concluded that there are likely two discrete populations consisting of an Okinawa/Philippines population and an unknown breeding group, both using the Ogasawara area as a migratory corridor. Given the uncertainty about the location of the other breeding ground, and the use of a common migratory corridor by the known group
The Hawaii population of humpback whales is separated by the greatest geographic distance from neighboring populations and was significantly different from other populations in both frequencies of mtDNA haplotypes and nDNA (microsatellite) alleles (Baker et al., 2013). The BRT therefore concluded that whales wintering in Hawaii constitute a discrete population.
In Mexico, available genetic and demographic studies indicate that humpback whales migrating to mainland Mexico and to the Revillagigedos Islands pass by the tip of Baja California. The BRT therefore concluded that humpback whales off Baja California should not be considered a discrete population. Further, the mainland population in Mexico does not differ significantly from the Revillagigedos population in its mtDNA haplotype frequencies (Baker et al., 2013). Photo-identification studies also indicate considerable movement of individuals between mainland and offshore island breeding areas in Mexico (Calambokidis et al., 2008). The BRT therefore concluded that mainland Mexico and the Revillagigedos populations are a single Mexico population discrete from all other populations
llagigedos population in its mtDNA haplotype frequencies (Baker et al., 2013). Photo-identification studies also indicate considerable movement of individuals between mainland and offshore island breeding areas in Mexico (Calambokidis et al., 2008). The BRT therefore concluded that mainland Mexico and the Revillagigedos populations are a single Mexico population discrete from all other populations.
In the eastern North Pacific, humpback whales in Central America have a unique mtDNA signature, as reflected in the frequencies of haplotypes (Baker et al., 2008a; Baker et al., 2008b). This frequency composition is significantly different from that in whales from all other breeding grounds in the North Pacific. The BRT concluded that humpback whales in Central America are a discrete population.
Thus while the BRT concluded there are five breeding populations of humpback whales in the North Pacific that meet the criteria for being discrete under the DPS Policy guidelines, we propose to identify four: (1) Western North Pacific (includes Okinawa/Philippines and the unidentified breeding area in the western North Pacific); (2) Hawaii (3) Mexico (includes mainland Mexico and the Revillagigedos Islands); and (4) Central America.
Significance
In evaluating whether any discrete population differed in its ecological characteristics from others, the BRT weighted ecological differences among feeding areas more heavily than among breeding areas, since it concluded that the ecological characteristics of humpback whales in their breeding ranges were largely similar among populations. In contrast, the BRT concluded whales largely foraging in different large marine ecosystems inhabit different ecological settings and that this is relevant in evaluating the significance of these populations. The BRT stated that, within the North Pacific, the Okinawa/Philippines, Hawaii, Mexico, and Central America populations tend to feed in different marine ecosystems, although there is some overlap
ontrast, the BRT concluded whales largely foraging in different large marine ecosystems inhabit different ecological settings and that this is relevant in evaluating the significance of these populations. The BRT stated that, within the North Pacific, the Okinawa/Philippines, Hawaii, Mexico, and Central America populations tend to feed in different marine ecosystems, although there is some overlap. The Western North Pacific population, which feeds in the Western Bering Sea (the Okinawa/Philippines population) and the Aleutian Islands (the unidentified breeding population), feeds in an ecosystem entirely different from the others in the North Pacific. The BRT also noted that the Central America population's breeding habitat is ecologically unique for the species as it is the only area where documented geographic overlap of populations that feed in different hemispheres occurs, potentially creating a conduit for genetic exchange between the two hemispheres. While a minority of members believed that this was an example of temporal and geographic overlap rather than a unique ecological setting, we conclude that the Central America population is significant to the ocean-basin based North Pacific subspecies because of its ecologically unique breeding habitat. We agree with the BRT that the Western North Pacific and Central America populations occupy unique ecological settings (unique breeding and feeding grounds for the Western North Pacific, unique breeding habitat for the Central America population), and therefore, they both are significant to the North Pacific subspecies.
The BRT noted that in the North Pacific Ocean, loss of the Okinawa/Philippines population would likely result in a significant gap in the North Pacific feeding range as these individuals are the only breeding population to migrate primarily to Russia, and loss of this population would therefore result in a loss of feeding range along the Russian coast
significant to the North Pacific subspecies.
The BRT noted that in the North Pacific Ocean, loss of the Okinawa/Philippines population would likely result in a significant gap in the North Pacific feeding range as these individuals are the only breeding population to migrate primarily to Russia, and loss of this population would therefore result in a loss of feeding range along the Russian coast. We concur with this conclusion, but because we have combined the unknown breeding group that feeds in the Aleutian Islands with the Okinawa/Philippines population, we need to assess whether this combined Western North Pacific population is significant to the ocean-basin based North Pacific subspecies. We conclude that the loss of the Western North Pacific population would result in a significant gap in the range of the North Pacific subspecies because if loss of the Okinawa/Philippines population would result in a significant gap, then the loss of a larger combined population would, too. The loss of humpback whales from the Hawaii breeding population would result in loss of humpbacks from the Hawaiian Islands, and this would represent a significant gap in the range of the North Pacific subspecies. We conclude that the Western North Pacific and the Hawaii populations both meet the significance criterion of the DPS Policy because loss of these populations would result in a significant gap in the range of the North Pacific subspecies. While the loss of the Mexico or Central America populations would not result in a significant gap in the range of their feeding grounds because their feeding grounds overlap, it would result in a significant gap in their breeding grounds, and therefore, we consider the Mexico and Central America populations also to be significant to the North Pacific subspecies.
The BRT discussed whether there was evidence for marked genetic divergence among any of the discrete populations
a significant gap in the range of their feeding grounds because their feeding grounds overlap, it would result in a significant gap in their breeding grounds, and therefore, we consider the Mexico and Central America populations also to be significant to the North Pacific subspecies.
The BRT discussed whether there was evidence for marked genetic divergence among any of the discrete populations. Although there was not clear agreement on the definition of “marked,” the BRT concluded that strong patterns of genetic differentiation in mtDNA sequence among most of the North Pacific breeding populations indicated marked genetic divergence, consistent with the conclusions in Baker et al. (2013). The overall level of differentiation among breeding populations within the North Pacific (F ST = 0.09) was similar to the level of divergence among ocean basins and is consistent with a relatively high degree of divergence of these populations. Further, in reviewing Baker et al. (2013), all populations that we have identified as discrete in the North Pacific are strongly differentiated from each other at the p-value 2 of 0.01 level or better, except for the Central America/Philippines pair, which are differentiated from each other at p-value of 0.05. Therefore, we agree with the BRT and conclude that all four of the discrete populations we have identified in the North Pacific (Western North Pacific, Hawaii, Mexico, and Central
2 The p-value is the probability of obtaining a test statistic result at least as extreme as the one that was actually observed, assuming that the null hypothesis is true; a small p-value (typically ≤ 0.05) indicates strong evidence against the null hypothesis; a null hypothesis is a general statement or default position that there is no relationship between two measured phenomena
o, and Central
2 The p-value is the probability of obtaining a test statistic result at least as extreme as the one that was actually observed, assuming that the null hypothesis is true; a small p-value (typically ≤ 0.05) indicates strong evidence against the null hypothesis; a null hypothesis is a general statement or default position that there is no relationship between two measured phenomena.
Although the petitioned North Pacific population could also satisfy the discreteness and significance criteria of the DPS Policy, there are other plausible and scientifically supported approaches to dividing the species into DPSs. We conclude that our modification of the BRT's approach for humpback whales in the North Pacific ( i.e., combining the unknown breeding group with the Okinawa/Philippines population) is more appropriate to further the purposes of the ESA because it represents a more risk-averse approach with respect to the unknown breeding group. As discussed above, identification of the Western North Pacific, Hawaii, Mexico, and Central America populations as DPSs is supported by the best available scientific and commercial information. We are exercising the discretion afforded to us as an expert agency charged with administering the ESA in the face of conflicting proposals ( i.e., petitions to delist North Pacific and Central North Pacific populations) to recognize these four populations as DPSs. Therefore, we will evaluate the status of each of these four DPSs in the North Pacific rather than recognizing a single North Pacific DPS and evaluating its combined status ( i.e., the approach offered by the Hawaii Fishermen's Alliance). The petition to delineate the North Pacific population as a DPS and “delist” it is therefore denied ( i.e., the petitioned action is not warranted). The petitioned Central North Pacific population is the same as the Hawaii DPS we have identified; therefore, we will evaluate the status of the Hawaii DPS to determine whether it is warranted for listing
ch offered by the Hawaii Fishermen's Alliance). The petition to delineate the North Pacific population as a DPS and “delist” it is therefore denied ( i.e., the petitioned action is not warranted). The petitioned Central North Pacific population is the same as the Hawaii DPS we have identified; therefore, we will evaluate the status of the Hawaii DPS to determine whether it is warranted for listing.
The following populations of the North Pacific humpback whale subspecies meet the discreteness and significance criteria for being a DPS under the DPS Policy: (1) Western North Pacific; (2) Hawaii; (3) Mexico; and (4) Central America.
Southern Hemisphere
Overview
There are at least eleven breeding grounds identified in the Southern Hemisphere at temperate latitudes: Brazil, Gabon and central West Africa, Mozambique, the Comoros Archipelago, Madagascar, West Australia, East Australia, New Caledonia, Tonga, French Polynesia, and the southeastern Pacific, (Stevick et al., 2006; Zerbini et al., 2006b; Engel and Martin, 2009; IWC, 2011). The Arabian Sea breeding ground is also at a temperate latitude and, while it is in the Northern Hemisphere, we discuss it here because we determined earlier that it was part of the Southern Hemisphere subspecies of the humpback whale.
The primary mating/calving ground of humpback whales in the western South Atlantic Ocean is the coast of Brazil. This population migrates to feeding grounds located east of the Scotia Sea near South Georgia and the South Sandwich Archipelagos (Stevick et al., 2006; Zerbini et al., 2006b; Engel et al., 2008; Engel and Martin, 2009; Zerbini et al., 2011). The winter breeding distribution of humpback whales in the southwestern Atlantic (June to December) is concentrated around the Abrolhos Bank region in Brazil (15-18° S.) and 500 km north, along the north coast of Bahia State and Espirito Santo State (Rossi-Santos et al., 2008) and near Salvador and Recife
06; Zerbini et al., 2006b; Engel et al., 2008; Engel and Martin, 2009; Zerbini et al., 2011). The winter breeding distribution of humpback whales in the southwestern Atlantic (June to December) is concentrated around the Abrolhos Bank region in Brazil (15-18° S.) and 500 km north, along the north coast of Bahia State and Espirito Santo State (Rossi-Santos et al., 2008) and near Salvador and Recife.
A humpback whale winter breeding and calving ground is located off central western Africa between ~6° S. and ~6° N. in the eastern Atlantic. Periods of peak abundance are found between July and September, with some whales still present as late as December and January in Angola, Gabon and São Tomé (Weir, 2007). The Gabon/Southwest Africa region appears to serve a variety of purposes with some individual whales remaining in the area through the year while some use the area for feeding and others for mating (Bettridge et al., 2015).
At least three winter breeding aggregations of humpback whales have been suggested in the southwestern Indian Ocean from historical whaling records and contemporary surveys (Wray and Martin, 1983; Best et al., 1998). One is associated with the mainland coastal waters of southeastern Africa, extending from Mozambique (24° S., Findlay et al., 1994) to as far north as Tanzania and southern Kenya (Wamukoya et al., 1996; Berggren et al., 2001; O'Connor et al., 2009). The second is found in the coastal waters of the northern Mozambique Channel Islands (Comoros Archipelago) and the southern Seychelles (Bettridge et al., 2015). The third is associated with the coastal waters of Madagascar (15-25° S.), best described in Antongil Bay on the east coast (Rosenbaum et al., 1997).
At least three migratory pathways to Antarctic summer feeding grounds in this region have been proposed using a compilation of data from surveys, whaling and acoustic records and sightings (Best et al., 1998)
rn Seychelles (Bettridge et al., 2015). The third is associated with the coastal waters of Madagascar (15-25° S.), best described in Antongil Bay on the east coast (Rosenbaum et al., 1997).
At least three migratory pathways to Antarctic summer feeding grounds in this region have been proposed using a compilation of data from surveys, whaling and acoustic records and sightings (Best et al., 1998). Humpback whale wintering grounds and coastal migratory routes in the eastern Indian Ocean are located between 15-35° S. along the west coast of Australia, with major calving grounds occurring in the Kimberley Region (15-18° S.) and resting areas on the southern migration at Exmouth Gulf (21° S.) and at Shark Bay (25° S.) (Bannister and Hedley, 2001; Jenner et al., 2001).
Humpback whales along the east coast of Australia are thought to breed primarily in waters inside the Great Barrier Reef (16-21° S.) (Chittleborough, 1965; Simmons and Marsh, 1986) and are seen as far north as Murray Island at ~10° S. (Simmons and Marsh, 1986). Discovery marks and satellite telemetry suggest east Australian whales feed in a broad swath of the Antarctic between 100° E. and 175° W., or that they frequent at least two feeding regions, one due south of eastern Australia stretching to the east beneath New Zealand, and one south of west Australia at ~100° E. and accessed via migration through Bass Strait.
The longitudinal distribution boundaries of humpback whales wintering in Oceania lie between ~160° E. (west of New Caledonia) and ~120° W. (east of French Polynesia) and latitudinally between 0° and 30° S. (Reeves et al., 1999), a range that includes American Samoa (United States), the Cook Islands, Fiji, French Polynesia (France), Republic of Kiribati, Nauru, New Caledonia (France), Norfolk Island, New Zealand, Niue, the Independent State of Samoa, Solomon Islands, Tokelau, Kingdom of Tonga, Tuvalu, Vanuatu, Wallis and Futuna (France)
ast of French Polynesia) and latitudinally between 0° and 30° S. (Reeves et al., 1999), a range that includes American Samoa (United States), the Cook Islands, Fiji, French Polynesia (France), Republic of Kiribati, Nauru, New Caledonia (France), Norfolk Island, New Zealand, Niue, the Independent State of Samoa, Solomon Islands, Tokelau, Kingdom of Tonga, Tuvalu, Vanuatu, Wallis and Futuna (France).
The wintertime breeding distribution of humpback whales in the southeastern Pacific (May to November) includes the coastal waters between Panama and northern Peru, with the main wintering areas concentrated in Colombia (Gorgona Island, Málaga Bay and Tribugá Gulf), Panama, and Ecuador. Low densities of whales are also found around the Galápagos Islands (Félix et al., 2006b), and coastal sightings have been made as far north as Costa Rica (Coco Island and Golfo Dulce, 8° N.) (Acevedo and Smultea, 1995; May-Collado et al., 2005). In the summer months, these whales migrate to feeding grounds located in waters off southern Chile, the Magellan Strait, and the Antarctic Peninsula (May-Collado et al., 2005; Félix et al., 2006b; Acevedo et al., 2008).
Sightings and survey data suggest that humpback whales in the Arabian Sea are primarily concentrated in the shallow near-shore areas off the coast of Oman, particularly in the Gulf of Masirah and Kuria Muria Islands regions (Minton, 2004); sightings and strandings suggest a population range that encompasses the northern Gulf of et al., 2010). Photo-identification re-sightings suggest humpback whales move seasonally between the Dhofar region (Kuria Muria Islands) in winter and the Gulf of Masirah to the north in summer, with similar re-sighting rates between and within regions (Minton et al., 2010b).
Despite extensive comparisons of photo-identification catalogues and genotyped individuals between Oman and the other Indian Ocean catalogues and genetic datasets, no matches have been detected between regions (Pomilla et al., 2006; Minton et al., 2010a)
ds) in winter and the Gulf of Masirah to the north in summer, with similar re-sighting rates between and within regions (Minton et al., 2010b).
Despite extensive comparisons of photo-identification catalogues and genotyped individuals between Oman and the other Indian Ocean catalogues and genetic datasets, no matches have been detected between regions (Pomilla et al., 2006; Minton et al., 2010a). Humpback whales from this region carry fewer and smaller barnacles than Southern Hemisphere whales, and do not exhibit the white oval scars indicative of cookie cutter shark ( Isistius brasiliensis ) bites, a feature commonly seen on some Southern Hemisphere humpback whales (Mikhalev, 1997).
Connections between the Arabian Sea population with the other Northern Hemisphere populations are highly unlikely as there is no accessible northward passage from the Arabian Sea. Furthermore, there are no mitochondrial DNA haplotypes or song patterns shared with North Pacific humpback whales (Whitehead, 1985; Rosenbaum et al., 2009); thus, on current evidence, and in the absence of comparisons with far western North Pacific humpbacks, it appears that whales from these populations have no recent biological connectivity. Analysis of fetal lengths in pregnant females killed by Soviet whalers clearly indicate that this population exhibits a Northern Hemisphere reproductive cycle, with births occurring in the boreal winter (Mikhalev, 1997).
Discreteness
Olavarría et al. (2007) analyzed patterns of mtDNA control region variation obtained from 1,112 samples from 6 breeding grounds in the South Pacific: New Caledonia, Tonga, Cook Islands, eastern Polynesia, Colombia, and Western Australia. Of these areas, the samples from Colombia were most differentiated (F ST = 0.06—0.08 in pairwise comparison to other areas). Pairwise divergence among the other areas was lower (F ST = 0.01—0.05). All pairwise comparisons were statistically >0, however, and indicated a lack of free exchange among these breeding areas
ledonia, Tonga, Cook Islands, eastern Polynesia, Colombia, and Western Australia. Of these areas, the samples from Colombia were most differentiated (F ST = 0.06—0.08 in pairwise comparison to other areas). Pairwise divergence among the other areas was lower (F ST = 0.01—0.05). All pairwise comparisons were statistically >0, however, and indicated a lack of free exchange among these breeding areas. Levels of haplotype diversity were generally very high (0.90—0.97). Rosenbaum et al. (2009) conducted a similar study of breeding areas in the Southern Atlantic and Western Indian Oceans, including the coastal areas of Brazil, Southwestern Africa, and Southeastern Africa. Levels of differentiation among these are statistically significant but relatively low, with F ST ranging from 0.003 (among two Southwestern African locations) to 0.017 (between Brazil and Southeastern Africa). Although there was some detectable differentiation among samples from Southwestern and Southeastern African coastal locations (B1/B2 and C1/C2/C3 International Whaling Commission (IWC) stocks, respectively), the levels of divergence within these areas were very low (F ST = 0.003-0.009 within the “B” stock and 0.002-0.005 within the “C” stock). The estimated number of migrants per generation was 26 between Brazil and Southwestern Africa, and 33 between Southwestern and Southeastern Africa.
A report on an IWC workshop devoted to Southern Hemisphere stock structure issues (IWC, 2011) recognizes at least seven “breeding stocks” associated with low-latitude, winter breeding grounds and, in some cases, migratory corridors. These seven breeding stocks are referred to alphabetically, from A to G, to distinguish them from the six management areas on feeding grounds of the Antarctic, referred to as Areas I-VI. The current breeding stock designations are southwestern Atlantic (A), southeastern Atlantic (B), southwestern Indian Ocean (C), southeastern Indian Ocean (D), southwestern Pacific (E), Oceania (E and F) and southeastern Pacific (G)
g stocks are referred to alphabetically, from A to G, to distinguish them from the six management areas on feeding grounds of the Antarctic, referred to as Areas I-VI. The current breeding stock designations are southwestern Atlantic (A), southeastern Atlantic (B), southwestern Indian Ocean (C), southeastern Indian Ocean (D), southwestern Pacific (E), Oceania (E and F) and southeastern Pacific (G). These designations have been subdivided to reflect improved understanding of substructure within some of these regions: Gabon (B1) and Southwest Africa (B2) in the southeastern Atlantic; Mozambique (C1), the Comoros Archipelago (C2), Madagascar (C3) and the Mascarene Islands (C4) in the southwestern Indian Ocean, east Australia (E1), New Caledonia (E2), Tonga (E3), the Cook Islands (F1) and French Polynesia (F2) in the southwestern Pacific and Oceania. The IWC has also chosen to include in this assessment, a year-round population of humpback whales found in the Arabian Sea, north of the equator in the northern Indian Ocean (formerly referred to as breeding stock X).
The BRT noted that the magnitude of mitochondrial DNA differentiation (as measured by F ST ) was generally lower among Southern Hemisphere breeding areas than it is in the Northern Hemisphere, indicating greater demographic connectivity among these areas. Even so, significant differentiation was present among major breeding areas, and the estimated number of migrants/generation among areas was small compared to the estimated sizes of the populations
differentiation (as measured by F ST ) was generally lower among Southern Hemisphere breeding areas than it is in the Northern Hemisphere, indicating greater demographic connectivity among these areas. Even so, significant differentiation was present among major breeding areas, and the estimated number of migrants/generation among areas was small compared to the estimated sizes of the populations.
The BRT members concluded that the seven breeding stocks of humpback whales currently formally recognized by the IWC in the Southern Hemisphere meet the criteria for being discrete populations under the DPS Policy guidelines, except that they agreed that the dividing line between IWC stocks E and F was between eastern Australia and Oceania (defined here to include New Caledonia, Tonga, Samoa, American Samoa, and French Polynesia), as there are large differences in the rates of recovery between these two regions, indicating they are demographically independent. Breeding populations in New Caledonia and east Australia are separate, but some overlap between the populations occurs: some whales bound for New Caledonia use the same migratory pathways as some whales headed past east Australia. There was consensus among the BRT to divide the Southern Hemisphere into seven discrete populations: Brazil, Gabon/Southwest Africa, Southeast Africa/Madagascar, West Australia, East Australia, Oceania (including New Caledonia, Tonga, Cook Islands, Samoa, American Samoa and French Polynesia), and Southeastern Pacific (Colombia and Ecuador). We agree with the BRT's conclusions, based on the significant mitochondrial DNA differentiation among major breeding populations.
With regard to the Arabian Sea population, nuclear and mitochondrial DNA diversity of humpback whales from Oman (up to 47 individuals sampled) is the lowest among all breeding grounds (Pomilla et al., 2006; Olavarría et al., 2007; Rosenbaum et al., 2009)
and Ecuador). We agree with the BRT's conclusions, based on the significant mitochondrial DNA differentiation among major breeding populations.
With regard to the Arabian Sea population, nuclear and mitochondrial DNA diversity of humpback whales from Oman (up to 47 individuals sampled) is the lowest among all breeding grounds (Pomilla et al., 2006; Olavarría et al., 2007; Rosenbaum et al., 2009). Mitochondrial DNA analysis revealed only eight distinct haplotypes, half of which are exclusive to Oman (not detected on other breeding grounds, Pomilla et al., 2006). Haplotype diversity at the mtDNA control region is markedly lower than in other populations (0.69 vs 0.90-0.98 for Southern Hemisphere populations and 0.84 for North Pacific populations) (Olavarría et al., 2007; Rosenbaum et al., 2009; Baker et al., 2013).
Genetic data (nuclear microsatellites and mitochondrial control region) and fluke pigmentation markings indicate that the Arabian Sea breeding population is significantly differentiated from Southern Indian Ocean breeding grounds (Rosenbaum et al., 2009). Nuclear genetic analysis suggests that this population is the most strongly and significantly differentiated in all ST range between Oman and Southern Indian Ocean breeding populations = 0.38-0.48) (Pomilla et al., 2006). Levels of mitochondrial DNA differentiation between Oman and other Indian Ocean breeding grounds are around ten times higher than among the other breeding grounds (pair-wise F ST range between Oman and other Indian Ocean breeding populations 0.11-0.15) (Rosenbaum et al., 2009).
The BRT concluded, and we agree, that the Arabian Sea population is discrete from all other populations because of its low haplotype diversity compared to Southern Hemisphere and North Pacific populations, its differentiation in mtDNA and nDNA markers, and fluke pigmentation differences between whales in the Arabian Sea and in the Southern Indian Ocean
ations 0.11-0.15) (Rosenbaum et al., 2009).
The BRT concluded, and we agree, that the Arabian Sea population is discrete from all other populations because of its low haplotype diversity compared to Southern Hemisphere and North Pacific populations, its differentiation in mtDNA and nDNA markers, and fluke pigmentation differences between whales in the Arabian Sea and in the Southern Indian Ocean.
Significance
The BRT noted that, within the Southern Hemisphere, most breeding populations feed in the same Antarctic marine ecosystem. One exception is the Brazil population, which feeds north of 60° S. in the South Georgia and South Sandwich Islands area (IWC, 2011). In addition to feeding in the Antarctic system, the Gabon/Southwest Africa population may also feed along the west coast of South Africa in the Benguela Current, but this is uncertain (IWC, 2011). Like the Central America population, the Southeastern Pacific breeding population may also be ecologically unique as it is the only population in the Southern Hemisphere to occupy an area also used by a Northern Hemisphere population. We conclude that the Brazil, Gabon/Southwest Africa, and Southeastern Pacific populations occupy unique ecological settings and are therefore significant to the Southern Hemisphere subspecies of the humpback whale.
For the Southern Hemisphere, determination of feeding range is more difficult since Antarctic feeding areas are less well studied and fewer connections between breeding and feeding populations have been made. However, some populations such as Brazil, Southwest Africa, Southeast Africa, and the Southeastern Pacific are believed to have fairly discrete and non-overlapping feeding areas, suggesting that if any of these feeding areas were lost it would, in combination with the lost breeding area, result in a significant gap in the range
r connections between breeding and feeding populations have been made. However, some populations such as Brazil, Southwest Africa, Southeast Africa, and the Southeastern Pacific are believed to have fairly discrete and non-overlapping feeding areas, suggesting that if any of these feeding areas were lost it would, in combination with the lost breeding area, result in a significant gap in the range. We conclude, therefore, that the Brazil, Gabon/Southwest Africa, Southeast Africa/Madagascar, and Southeastern Pacific populations are significant to the Southern Hemisphere subspecies of the humpback whale because their loss would result in significant gaps in the range of the Southern Hemisphere subspecies. Further, we believe that the loss of the West Australia, East Australia, and Oceania populations would also result in significant gaps in the ranges of the Southern Hemisphere subspecies because their non-overlapping breeding ranges are quite extensive.
In the Southern Hemisphere, the Southeastern Pacific population is the only breeding population that contains a genetic signal from Northern Hemisphere populations, giving it a unique genetic signature within the Southern Hemisphere (Baker et al., 1993; Baker and Medrano-González, 2002). It is also the most divergent of any of the Southern Hemisphere populations (Olavarría et al., 2007). In addition, individuals in this region are morphologically distinct as they have darker pectoral fin coloration than other individuals in the Southern Hemisphere (Chittleborough, 1965), although the genetic basis for this trait is not known. Nonetheless, a majority of the BRT concluded that the Southeastern Pacific population was sufficiently differentiated so as to differ `markedly' in its genetic characteristics from other Southern Hemisphere populations
istinct as they have darker pectoral fin coloration than other individuals in the Southern Hemisphere (Chittleborough, 1965), although the genetic basis for this trait is not known. Nonetheless, a majority of the BRT concluded that the Southeastern Pacific population was sufficiently differentiated so as to differ `markedly' in its genetic characteristics from other Southern Hemisphere populations. In contrast, all other Southern Hemisphere populations were characterized by generally low levels of differentiation among them, consistent with demographically discrete populations but not necessarily with marked genetic divergence associated with long-term isolation (Olavarría et al., 2007; Rosenbaum et al., 2009). We conclude that the Southeastern Pacific population of the humpback whale is significant to the Southern Hemisphere population of the humpback whale because it differs markedly in its genetic characteristics from other Southern Hemisphere populations. We conclude that each of the seven discrete Southern Hemisphere populations (Brazil, Gabon/Southwest Africa, Southeast Africa/Madagascar, West Australia, East Australia, Oceania, and Southeastern Pacific) satisfies at least one significance factor of the DPS Policy, and, therefore, we consider them to be DPSs.
The Arabian Sea population persists year-round in a monsoon driven tropical ecosystem with highly contrasting seasonal wind and resulting upwelling patterns. The BRT therefore concluded that this population persists in a unique ecological setting. The Arabian Sea population segment does not migrate extensively, but instead feeds and breeds in the same geographic location. No other humpback whale populations occupy this area and hence, a loss of the Arabian Sea population would result in a significant gap in the range of the Southern Hemisphere subspecies. The BRT also concluded that the Arabian Sea population differs markedly in its genetic characteristics from other populations in the Indian Ocean and worldwide
ead feeds and breeds in the same geographic location. No other humpback whale populations occupy this area and hence, a loss of the Arabian Sea population would result in a significant gap in the range of the Southern Hemisphere subspecies. The BRT also concluded that the Arabian Sea population differs markedly in its genetic characteristics from other populations in the Indian Ocean and worldwide. The degree of genetic differentiation at multiple genetic markers between this population and other populations is similar to or greater than the degree of divergence among the North Pacific, North Atlantic, and Southern Hemisphere areas. The BRT unanimously concluded that the Arabian Sea population would be considered a DPS under any global taxonomic scenario, due to its marked genetic divergence from all other populations and unique ecological setting. We agree that the Arabian Sea population occupies a unique ecological setting, its loss would result in a significant gap in the range of the Southern Hemisphere subspecies, and it differs markedly in its genetic characteristics from other populations. Therefore, it meets the significance criterion of the DPS policy, and we identify the Arabian Sea population as a DPS.
Extinction Risk Assessment
The BRT discussed the relationship between population size and trend and extinction risk, citing relevant literature on small population size, environmental and demographic stochasticity, genetic effects, catastrophes, and extinction risk ( e.g., Franklin, 1980; Soulé, 1980; Gilpin and Soulé, 1986; Allendorf et al., 1987; Goodman, 1987; Mace and Lande, 1991; Frankham, 1995; Lande, 1998; Lynch and Blanchard, 1998; Lynch and Lande, 1998; Frankham, 1999; Brook et al., 2006; Mace et al., 2008) and concluding that population size criteria similar to those described in Mace et al. (2008) (International Union for Conservation of Nature and Natural Resources (IUCN) Red List criteria) could be considered carefully but not used as the sole criterion for evaluating extinction risk
de, 1998; Lynch and Blanchard, 1998; Lynch and Lande, 1998; Frankham, 1999; Brook et al., 2006; Mace et al., 2008) and concluding that population size criteria similar to those described in Mace et al. (2008) (International Union for Conservation of Nature and Natural Resources (IUCN) Red List criteria) could be considered carefully but not used as the sole criterion for evaluating extinction risk. The criteria the BRT considered are that a DPS with a total population size >2,000 was not likely to be at risk due to low abundance alone, a DPS with a population size <2,000 would be at increasing risk from factors associated with low abundance (and the lower the population size, the greater the risk), a DPS with a population size <500 would be at high risk due to low abundance, and a DPS with a population size <100 would be at extremely high risk due to
The BRT considered abundance and trend information and categorized each DPS' abundance as described above and indicated whether the population trend was increasing strongly, increasing moderately, stable/little trend, or declining. The BRT included an “unknown” category where data were not sufficient to detect a trend. To express uncertainty in abundance or trend information for any DPS, the BRT categorized abundance and trend in more than one category. As noted above, while NMFS' 1991 Humpback Whale Recovery Plan recommended that populations grow to at least 60 percent of their historical (pre-hunting) abundance to be considered recovered, it did not identify specific numerical targets due to uncertainty surrounding historical abundance levels. So, the plan suggested an interim goal of doubling the population sizes within 20 years, which corresponds to an annual growth rate of about 3.5 percent
covery Plan recommended that populations grow to at least 60 percent of their historical (pre-hunting) abundance to be considered recovered, it did not identify specific numerical targets due to uncertainty surrounding historical abundance levels. So, the plan suggested an interim goal of doubling the population sizes within 20 years, which corresponds to an annual growth rate of about 3.5 percent. Because historical size of humpback whale populations continues to be uncertain (Bettridge et al., 2015) two decades after the recovery plan was finalized, and humpback whale survey periods have not spanned 20 years since issuance of the 1991 recovery plan, data are not available to evaluate the status of humpback whale populations against these goals. Therefore, the BRT focused its biological risk analysis primarily on recent abundance trends and whether absolute abundance was sufficient for biological viability in light of consideration of the factors under Section 4(a)(1). This is a valid approach that we often use to evaluate the risk of extinction to populations.
The BRT also ranked the severity of 16 current or imminent threats to the humpback whale DPSs (1 = low or none, threat is likely to have no or minor impact on population size or the growth rate; 2 = medium, threat is likely to moderately reduce the population size or the growth rate of the population; 3 = high, threat is likely to seriously reduce the population size or the growth rate of the population, 4 = very high, threat is likely to eliminate the DPS, unknown = severity of threat is unknown) and also indicated whether the trend of any threat was increasing.
Finally, the BRT members assessed the risk of extinction for each DPS by distributing 100 likelihood points among 3 categories of extinction risk: (1) High Risk = a species or DPS has productivity, spatial structure, genetic diversity, and/or a level of abundance that place(s) its persistence in question
ity of threat is unknown) and also indicated whether the trend of any threat was increasing.
Finally, the BRT members assessed the risk of extinction for each DPS by distributing 100 likelihood points among 3 categories of extinction risk: (1) High Risk = a species or DPS has productivity, spatial structure, genetic diversity, and/or a level of abundance that place(s) its persistence in question. The demographics of a species/DPS at such a high level of risk may be highly uncertain and strongly influenced by stochastic and/or small population effects. Similarly, a species/DPS may be at high risk of extinction if it faces clear and present threats ( e.g., imminent destruction, modification, or curtailment of its habitat; or disease epidemic) that are likely to create

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2015-09010. Check the current official text before relying on it. Not legal advice.