Status Review of the Sakhalin Bay-Amur River Beluga 

Whale (Delphinapterus leucas) under the Marine 

Mammal Protection Act

Photo Credit: Laura Morse (NOAA), Permit 782-1719

Shannon Bettridge, Robert L. Brownell Jr., Melissa Andersen Garcia, 

Rod C. Hobbs, Cheri L. McCarty, Richard D. Methot Jr., Debra L. Palka, 

Patricia E. Rosel, Kathryn S. Swails, and Barbara L. Taylor

U.S. Department of Commerce

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

NOAA Technical Memorandum NMFS-OPR-51

March 2016

Status Review of the Sakhalin Bay-Amur River

Beluga Whale (Delphinapterus leucas) under the

Marine Mammal Protection Act

Shannon Bettridge, Robert L. Brownell Jr., Melissa Andersen Garcia, Rod C. Hobbs, 

Cheri L. McCarty, Richard D. Methot Jr., Debra L. Palka, Patricia E. Rosel, Kathryn S. Swails,

and Barbara L. Taylor 

NOAA Technical Memorandum NMFS-OPR-51

March 2016

U.S. Department of Commerce

Penny S. Pritzker, Secretary 

National Oceanic and Atmospheric Administration

Kathryn D. Sullivan, Administrator

National Marine Fisheries Service

Eileen Sobeck, Assistant Administrator for Fisheries
ii

Acknowledgements

The Beluga Whale Status Review Team would like to thank the Marine Mammal Commission for 

coordinating a peer review of this report, and Nancy Young for invaluable review and 

contributions to the report. 

Recommended citation:

Bettridge, S., R. L. Brownell Jr., M. A. Garcia, R. C. Hobbs, C. L. McCarty, R. D. Methot Jr., D. L.

Palka, P. E. Rosel, K. S. Swails, and B. L. Taylor. 2016. Status Review of the Sakhalin Bay-Amur 

River Beluga Whale (Delphinapterus leucas) under the Marine Mammal Protection Act. U.S. 

Dept. of Commer., NOAA. NOAA Technical Memorandum NMFS-OPR-51, 34 p.

Copies of this report may be obtained from:

Office of Protected Resources

National Oceanic and Atmospheric Administration 

1315 East-West Highway 

Silver Spring, MD 20910

Or online at:

http://www.nmfs.noaa.gov/pr/publications/techmemos.htm
iii

Beluga Whale Status Review Team

Shannon Bettridge

National Marine Fisheries Service

Office of Protected Resources

Robert L. Brownell, Jr.

National Marine Fisheries Service

Southwest Fisheries Science Center

Melissa Andersen Garcia

National Marine Fisheries Service

Office of International Affairs 

and Seafood Inspection

Rod C. Hobbs

National Marine Fisheries Service

Alaska Fisheries Science Center

Cheri L. McCarty

National Marine Fisheries Service

Office of International Affairs 

and Seafood Inspection

Richard D. Methot, Jr.

National Marine Fisheries Service

Northwest Fisheries Science Center

Debra L. Palka 

National Marine Fisheries Service

Northeast Fisheries Science Center

Patricia E. Rosel 

National Marine Fisheries Service

Southeast Fisheries Science Center

Kathryn S. Swails

National Marine Fisheries Service

Greater Atlantic Regional Fisheries Office

Barbara L. Taylor

National Marine Fisheries Service

Southwest Fisheries Science Center

v 

Table of Contents

Beluga Whale Status Review Team.......................................................................................................... iii

List of Figures.......................................................................................................................................... vii

List of Acronyms..................................................................................................................................... viii

1. Introduction ............................................................................................................................................. 1

2. Petition to designate the Sakhalin Bay-Amur River stock of beluga whales as depleted under the

MMPA ........................................................................................................................................................... 2

2.1 Summary of petition ........................................................................................................................... 2

2.2 Agency finding..................................................................................................................................... 3

3. Distribution, abundance, and threats to beluga whales in the Sakhalin Bay-Amur River ....................... 3

3.1 Distribution and migration.................................................................................................................. 3

3.2 Abundance estimates of beluga whales in the Sakhalin Bay-Amur River beluga whale population.. 5

3.3 Current threats to Sea of Okhotsk beluga whales.............................................................................. 5

4. Response to petition - Do the Sakhalin Bay-Amur River beluga whales constitute a stock under the

Marine Mammal Protection Act? ................................................................................................................. 5

4.1 Review of MMPA definition of stock and summary of beluga whale stock delineation under the 

MMPA, IWC and IUCN............................................................................................................................... 5

4.1.1 The Marine Mammal Protection Act and definition of “stock”................................................... 5

4.1.2 Identifying marine mammal stocks pursuant to the MMPA ....................................................... 8

4.1.3 International Whaling Commission beluga whale stock delineation ........................................10

4.1.4 International Union for Conservation of Nature (IUCN) beluga whale stock delineation.........10

4.2. Response to petition - review of stock structure.............................................................................11

4.2.1 Rationale for demographic independence of Sakhalin Bay-Amur River beluga whales............11

4.2.2 Rationale against demographic independence of Sakhalin Bay-Amur-River beluga whales ....14

4.3 Conclusion about demographic independence ................................................................................15

4.3.1 Structured Expert Decision Making ...........................................................................................15

4.3.2 Beluga Whale Status Review Team SEDM .................................................................................16

4.3.3 Structured Expert Decision Making Summary ...........................................................................20

5. Response to petition - Estimation of depletion level for Sakhalin Bay-Amur River belugas.................21

5.1 Back calculation of carrying capacity ................................................................................................21

5.2 Application of back-calculation to Sakhalin Bay–Amur River beluga whales...................................21

5.2.1 Data Input: Catch History...........................................................................................................22
vi

5.2.2 Data Input: 2009-2010 Abundance Estimate.............................................................................23

5.2.3 Results: Estimated Carrying Capacity and Depletion Level........................................................24

6. Summary ................................................................................................................................................25

Literature Cited...........................................................................................................................................27

Appendix .....................................................................................................................................................31
vii

List of Figures

Figure 1. Map of beluga whale global distribution....................................................................................... 3

Figure 2. Map of Sea of Okhotsk................................................................................................................... 4

Figure 3. Original figure 1 from Taylor (1997). Distribution of five pristine populations (a), versus 

potential distributions after 50% of the total abundance is removed (b-d). Width represents 

abundance; length represents distance................................................................................................. 8

Figure 4. Approximate distribution of beluga whales in Alaska waters. The dark shading displays the 

summer distribution of the five stocks. Winter distributions are depicted with lighter shading. 

Source: Angliss and Allen (2015). .........................................................................................................10

Figure 5. Map of Alaska beluga whale areas...............................................................................................13

Figure 6. Annual estimated abundance (blue line/open circles) and annual takes (black line/red circles) 

from the base case population model. Takes peaked in 1933 when the population had already 

declined by > 50%. The population abundance reached a minimum in 1960, then slowly began to 

increase. ...............................................................................................................................................25
viii

List of Acronyms

BRT biological review team

DNA deoxyribonucleic acid

DPS distinct population segment

EEZ Exclusive Economic Zone

ESA Endangered Species Act

GAMMS Guidelines for Assessing Marine Mammal Stocks 

IUCN International Union for Conservation of Nature

IWC International Whaling Commission

IWC SC International Whaling Commission’s Scientific Committee

K carrying capacity

MMPA Marine Mammal Protection Act

MNPL maximum net productivity level

mtDNA mitochondrial DNA

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration

OSP optimum sustainable population

PBR potential biological removal

PCFG Pacific Coast feeding group

SAR stock assessment report

SEDM structured expert decision making

Team status review team
1 

Status Review of the Sakhalin Bay-Amur River Beluga Whales

1. Introduction

Section 3(1)(A) of the Marine Mammal Protection Act (MMPA) (16 U.S.C. 1362(1)(A)) defines the term 

“depletion” or “depleted” to include any case in which “the Secretary, after consultation with the 

Marine Mammal Commission and the Committee of Scientific Advisors on Marine 

Mammals...determines that a species or a population stock is below its optimum sustainable 

population.” Section 3(9) of the MMPA (16 U.S.C. 1362(9)) defines “optimum sustainable population 

[OSP]...with respect to any population stock, [as] the number of animals which will result in the 

maximum productivity of the population or the species, keeping in mind the carrying capacity [(K)] of 

the habitat and the health of the ecosystem of which they form a constituent element.” The National 

Oceanic and Atmospheric Administration’s (NOAA) National Marine Fisheries Service’s (NMFS) 

regulations at 50 CFR 216.3 clarify the definition of OSP as a population size that falls within a range 

from the population level of a given species or stock that is the largest supportable within the ecosystem 

(i.e., carrying capacity, or K) to its maximum net productivity level (MNPL). MNPL is the population 

abundance that results in the greatest net annual increment in population numbers resulting from 

additions to the population from reproduction, less losses due to natural mortality. Historically, MNPL 

has been expressed as a range of values (between 50 and 70 percent of K) determined on a theoretical 

basis by estimating what stock size, in relation to the historical stock size, will produce the maximum net 

increase in population (42 FR 12010, March 1, 1977). In practice, NMFS has determined that stocks with 

populations under the mid-point of this range (i.e., 60 percent of K) are depleted (42 FR 64548, 

December 27, 1977; 45 FR 72178, October 31, 1980). 

The MMPA allows interested parties to petition NMFS to initiate a status review to determine whether a 

species or stock of marine mammals should be designated as depleted. Section 115(a)(3) of the MMPA 

(16 U.S.C. 1383b(a)(3)) requires NMFS to publish a notice in the Federal Register that such a petition has 

been received and is available for public review. Within 60 days of receiving a petition, NMFS must 

publish a finding in the Federal Register as to whether the petition presents substantial information 

indicating that the petitioned action may be warranted. 

If NMFS makes a positive 60-day finding, NMFS must promptly initiate a review of the status of the 

petitioned population stock of marine mammals. No later than 210 days after receipt of the petition, 

NMFS must publish a proposed rule as to the status of the species or stock, along with the reasons 

underlying the proposed status determination. Following a 60-day minimum comment period on the 

proposed rule, NMFS must publish a final rule within 90 days of the close of the comment period on the 

proposed rule. 
2

2. Petition to designate the Sakhalin Bay-Amur River stock of beluga whales as 

depleted under the MMPA

2.1 Summary of petition

On April 23, 2014, NMFS received a petition from the Animal Welfare Institute, Whale and Dolphin 

Conservation, Cetacean Society International, and Earth Island Institute (petitioners) to “designate the 

Sakhalin Bay-Amur River stock of beluga whales as depleted under the MMPA.” The petition presents 

information asserting that NMFS has authority to designate stocks outside of U.S. jurisdictional waters 

as depleted. The petition asserts the Sakhalin Bay-Amur River population of beluga whales comprises a 

stock under the MMPA and that this stock is below its OSP and qualifies for a depleted designation. The 

petitioners also argue that the stock continues to decline and faces a number of threats. The petition 

alleges that the causes of this stock’s decline include: large-scale commercial hunting from 1915-1963

and renewed commercial hunting in 1999; unsustainable removal for captive display; incidental 

mortality from fishing operations; accidental drowning during live-capture operations for captive public 

display; vessel strikes; and other anthropogenic threats including oil and gas development, expansion of 

fisheries, pollution and climate change.

The petitioners suggest that genetic and satellite tag tracking data indicate the existence of at least two 

beluga whale populations in the Sea of Okhotsk: one in the northeastern region and the other in the 

western region. The petition goes on to present information suggesting that the beluga whales in the 

western region of the Sea of Okhotsk comprise, and should be managed as, more than one stock. The 

petitioners state that for the beluga whales in the western region of the Sea of Okhotsk, evidence of 

distinct matrilineal lines, separate summer birthing and feeding distributions, and high site fidelity, 

indicate that the region supports more than one stock of beluga whales, including a distinct Sakhalin 

Bay-Amur River stock. The petitioners state that the International Union for Conservation of Nature 

(IUCN) has recognized the existence of a distinct Sakhalin Bay-Amur River stock (see Reeves et al. 2011). 

Additionally, the petition asserts that the International Whaling Commission’s Scientific Committee (IWC 

SC) recognized the Sakhalin-Amur beluga whales as a separate stock in 1999. 1

 

The petition presents information from 2009 and 2010 aerial surveys indicating that the best current 

abundance estimate of the Sakhalin Bay-Amur River beluga whales is 3,961 whales (see Reeves et al. 

2011). The petitioners assert that this estimate is well below 60 percent of the lowest available estimate

of historical abundance (7,000-10,000; Berzin and Vladimirov 1990), and that the Sakhalin Bay-Amur 

River population of beluga whales therefore qualifies as depleted. The petition also notes that, after 

reviewing the available information on the status of beluga whales globally, the IWC SC described the 

Sakhalin-Amur- stock of beluga whales as having a “likely depleted status relative to historical 

abundance” (see IWC Report of the Sub-Committee on Small Cetaceans 2000).2

 

 1 It should be noted that the IUCN and IWC’s use of the term “stock” differs from the definition of a stock as 

defined by the MMPA and used by NOAA. 

2 It should be noted that the IWC’s determination of “depletion” differs from the MMPA’s depletion definition. 
3

2.2 Agency finding

NMFS reviewed the information presented in the petition, readily available in the agency’s files, and 

submitted through the public comment process, and determined that the petition presented substantial 

information indicating that the petitioned action may be warranted. Pursuant to section 115(a)(3)(B) of 

the MMPA, NMFS published its finding in the Federal Register on August 1, 2014 and informed the 

public that the agency would promptly initiate a status review (79 FR 44733). NMFS then established a 

status review team (Team) to conduct the review. 

3. Distribution, abundance, and threats to beluga whales in the Sakhalin Bay-Amur 

River

3.1 Distribution and migration

Beluga whales (Delphinapterus leucas) are small, toothed whales distributed throughout the Arctic, and

inhabit subarctic regions of Russia, Greenland, and North America (Figure 1). They are found in the 

Arctic Ocean and its adjoining seas, including the Sea of Okhotsk, the Bering Sea, the Gulf of Alaska, the 

Beaufort Sea, Baffin Bay, Hudson Bay, and the Gulf of St. Lawrence. Beluga whales may also be found in 

large river deltas and upstream at certain times of the year. 

Figure 1. Map of beluga whale global distribution.

Beluga whale distributions show marked seasonal changes. Generally, there is a winter distribution in 

which the whales are found in deeper waters often associated with pack ice. In the spring and summer, 

there is a calving/feeding distribution in which the whales are found in warmer coastal estuaries, bays, 

and rivers where they may molt (Finley 1982) and give birth to and care for their calves (Sergeant and 

Brodie 1969). Migration between wintering and summering grounds may cover thousands of kilometers

or may occur within a large bay or estuary (Reeves 1990). 
4

Stock boundaries sometimes overlap spatially, and in such cases, the geographical delineation of beluga 

whale (also called white whale) stocks must have a temporal component. Migrating whales from 

different stocks may approach and move past a given site in “waves,” while a summer “resident” stock 

moves into that same area for an extended period. For example, the Eastern Chukchi Sea stock is 

temporally delineated as the group of whales that arrives in Kotzebue Sound or Kasegaluk Lagoon as the 

ice begins to break up and remains there for at least several weeks. Earlier in the year, whales from the 

Beaufort Sea stock move through this area in the spring lead system. Thus, the annual catch at Alaskan 

villages such as Point Hope, Kivalina and Barrow can consist of whales from both of these stocks, 

depending on the time of year the whales are taken.

Beluga whales are found throughout much of the Sea of Okhotsk, including Shelikov Bay in the northeast 

and throughout the western Sea of Okhotsk including the Amur River estuary, the nearshore areas of 

Sakhalin Bay, in the large bays to the west, Nikolaya Bay, Ulbansky Bay, Tugursky Bay and Udskaya Bay, 

and among the Shantar Islands (Fig. 3). Use of the bays and estuaries in the western Sea of Okhotsk is 

limited primarily to summer months; the whales move into the ice-covered offshore areas of the 

western Sea of Okhotsk in the winter (Melnikov 1999). In the Sakhalin Bay and Amur Estuary region, 

whales’ arrival and departure appear to be linked to fish runs (Solovyev et al. 2015). In this document, 

we refer to the beluga whales found in the Amur River estuary and the nearshore areas of Sakhalin Bay 

(Figure 2) during summer as the Sakhalin Bay-Amur River beluga whales. Beluga whales are not found 

to the south of the Amur River estuary area, though whales in the region have been seen arriving from 

the direction of Tatar Strait to the south (Solovyev et al. 2015).

Figure 2. Map of Sea of Okhotsk
5

3.2 Abundance estimates of beluga whales in the Sakhalin Bay-Amur River beluga whale 

population

The best available estimate of abundance beluga whales in the Sakhalin Bay-Amur River area is 3,961

(Reeves et al. 2011). This estimate was based on surveys conducted in 2009 and 2010 (Shpak et al. 

2011) and was further reviewed by an IUCN scientific panel of beluga whale experts (Reeves et al. 2011). 

The minimum population estimate for the Sakhalin-Amur population was determined to be 2,891 

(Reeves et al. 2011). Comparable direct estimates of abundance from other areas are not available, 

hence direct estimates of trends are not feasible.

3.3 Current threats to Sea of Okhotsk beluga whales

Information on potential sources of serious injury and mortality is limited for the Sea of Okhotsk beluga 

whales. The IUCN panel (Reeves et al. 2011) identified subsistence harvest, death during live-capture

for public display, entanglement in fishing gear, vessel strike, climate change, and pollution as human 

activities that may result in serious injury or mortality to Sea of Okhotsk beluga whales. The greatest 

amount of available information is from the annual take from the commercial hunt. As noted in the 

petition and the IUCN review, monitoring of other types of mortality in the Sea of Okhotsk is low, if 

existent at all, and information on possible threats and sources of mortality in Sea of Okhotsk beluga 

whales is highlighted by a lack of substantiated data, and is largely anecdotal. The IUCN panel 

emphasized the lack of data regarding other sources of mortality, and noted that “any animals taken by 

humans, including those killed or injured in fishing gear, struck by vessels, or accidentally drowned 

during live-capture operations, should be considered when evaluating the sustainability of any level of 

intentional removals” (Reeves et al. 2011). 

Although the full extent of other sources of mortality cannot be determined, there is reason to believe 

that a suite of activities that threaten beluga whales in this area do occur (Reeves et al. 2011), and they

cannot be fully discounted or assumed to be zero. 

4. Response to petition - Do the Sakhalin Bay-Amur River beluga whales constitute a 

stock under the Marine Mammal Protection Act?

4.1 Review of MMPA definition of stock and summary of beluga whale stock delineation 

under the MMPA, IWC and IUCN

Section 115 of the MMPA grants NMFS the authority to designate as depleted a species or stock of 

marine mammals. Because the petitioners did not petition NMFS to designate an entire species as 

depleted, the first question that the Team considered is whether the Sakhalin Bay-Amur River 

population of beluga whales constitutes a stock, as defined under the MMPA. 

4.1.1 The Marine Mammal Protection Act and definition of “stock”

The MMPA defines “population stock” as “a group of marine mammals of the same species or smaller 

taxa in a common spatial arrangement, that interbreed when mature” (MMPA section 3(11)).

Section 117 of the MMPA requires NMFS and the U.S. Fish and Wildlife Service to prepare stock 

assessment reports (SARs) for all marine mammal stocks occurring in waters under U.S. jurisdiction. 
6

The SARs contain information on the identity and geographic range of the stock, population statistics 

related to abundance, trend, annual productivity, notable habitat concerns, and human-caused 

mortality and serious injury by source. 

NMFS convened a workshop in June 1994 to develop guidelines for preparing SARs. The Guidelines for 

Assessing Marine Mammal Stocks (Wade and Angliss 1997; subsequently revised in NMFS 2005) 

(hereafter referred to as GAMMS) were devised by NMFS to ensure that SARs are developed in a 

repeatable, transparent manner consistent with the intent of the MMPA. These guidelines are followed 

for all marine mammal stock assessment reports, and have provided guidance for revisions to stock 

structure (e.g., identifying prospective stocks). The current guidelines, GAMMS II (NMFS 2005), have the 

following section on stock definition:

“Many types of information can be used to identify stocks of a species: e.g., distribution and 

movements, population trends, morphological differences, differences in life history, genetic 

differences, contaminants and natural isotope loads, parasite differences, and oceanographic 

habitat differences. Different population responses (e.g., different trends in abundance) 

between geographic regions is also an indicator of stock structure, as populations with 

different trends are not strongly linked demographically. When different types of evidence are 

available to identify stock structure, the report must discuss inferences made from the 

different types of evidence and how these inferences were integrated to identify the stock. 

“Evidence of morphological or genetic differences in animals from different geographic regions 

indicates that these populations are reproductively isolated. Reproductive isolation is proof of 

demographic isolation, and, thus, separate management is appropriate when such differences 

are found. Demographic isolation3 means that the population dynamics of the affected group is 

more a consequence of births and deaths within the group (internal dynamics) rather than 

immigration or emigration (external dynamics). Thus, the exchange of individuals between 

population stocks is not great enough to prevent the depletion of one of the populations as a 

result of increased mortality or lower birth rates.

“Failure to detect differences, however, does not mean that populations are not 

demographically or reproductively isolated. Dispersal rates, though sufficiently high to 

homogenize morphological or genetic differences detectable between putative populations, 

may still be insufficient to deliver enough recruits from an unexploited population (source) to 

an adjacent exploited population (sink) so that the latter remains a functioning element of its 

ecosystem.

 3 A further revision, GAMMS III, is not yet final, but proposed changing “demographically isolated” to 

“demographically independent,” since this was the intent of GAMMS II and is how the Agency has been 

interpreting the MMPA definition. NMFS considers in addition, the term “demographic independence” a better 

description than the term “demographic isolation”. As such, this document will use the term “demographic 

independence”.
7

“Insufficient dispersal between populations where one bears the brunt of exploitation coupled 

with their inappropriate pooling for management could easily result in failure to meet MMPA 

objectives. For example, it is common to have human-caused mortality restricted to a portion 

of a species’ range. Such concentrated mortality (if of a large magnitude) could lead to 

population fragmentation, a reduction in range, or even the loss of undetected populations, 

and would only be mitigated by high immigration rates from adjacent areas.

“Therefore, careful consideration needs to be given to how stocks are identified. In particular, 

where mortality is greater than a Potential Biological Removal (PBR) level calculated from the 

abundance just within the oceanographic region where the human-caused mortality occurs, 

serious consideration should be given to identifying an appropriate management unit in this 

region. In the absence of adequate information on stock structure and fisheries mortality, a 

species’ range within an ocean should be divided into stocks that represent defensible 

management units. Examples of such management units include distinct oceanographic 

regions, semi-isolated habitat areas, and areas of higher density of the species that are 

separated by relatively lower density areas. Such areas have often been found to represent 

true biological stocks where sufficient information is available. In cases where there are large 

geographic areas from which data on stock structure of marine mammals are lacking, stock 

structure from other parts of the species’ range may be used to draw inferences as to the likely 

geographic size of stocks. There is no intent to identify stocks that are clearly too small to 

represent demographically isolated biological populations, but it is noted that for some species 

genetic and other biological information has confirmed the likely existence of stocks of 

relatively small spatial scale, such as within Puget Sound, WA, the Gulf of Maine, or Cook Inlet,

AK.”

In practice, NMFS has interpreted the language “interbreed when mature” in the MMPA definition of 

stock to mean cases in which either: 

1. Mating occurs primarily among members of the same demographically independent group, or

2. The group migrates seasonally to a breeding ground where its members breed with members of 

the same group as well as with members of other demographically distinct groups which have 

migrated to the same breeding ground from a different feeding ground.

Taylor (1997) explored the definition of population in light of the management objectives of the MMPA, 

and developed a model to examine dispersal rates and provided several examples (Figure 3) where 

localized removals lead to local extirpation, which arguably violates the ecosystem goals of the MMPA. If

human caused mortality for the entire population were to act disproportionately on certain groups, 

those groups could be extirpated, depending on whether the amount of immigration from other groups 

was below a certain dispersal rate threshold (which varied with simulation conditions). For all models 

tested, when dispersal fell below a few percent of the population per year, recruitment into the 

population with human caused mortality was insufficient to compensate for removal, and population 

levels declined below those sought by management objectives. Therefore, Taylor (1997) concluded that 

populations should be managed separately if dispersal between them is less than several percent per 

year. Further clarification of the different interpretations of the term “stocks” under the MMPA, the 
8

Magnuson-Stevens Fisheries Conservation and Management Act and the Endangered Species Act (ESA) 

(where legal protection is given to Distinct Population Segments (DPS) have been provided in Eagle et al. 

(2008).

Figure 3. Original figure 1 from Taylor (1997). Distribution of five pristine populations (a), versus potential 

distributions after 50% of the total abundance is removed (b-d). Width represents abundance; length represents 

distance.

4.1.2 Identifying marine mammal stocks pursuant to the MMPA

Most U.S. marine mammal stocks remain as originally delimited following the 1994 amendments to the 

MMPA; however, several new stocks have been proposed and accepted since that time. These stock 

designations provide context to how the GAMMS definition of “stock” has been implemented. The 

cases most relevant to the Sakhalin Bay-Amur River beluga whale stock question posed here are those 

involving interpretation of genetic data. Selected cases follow. 

Example: Harbor seals and harbor porpoises

Several stocks of harbor seals (Phoca vitulina) (O'Corry-Crowe et al. 2003) and harbor porpoises

(Phocoena phocoena) (Chivers et al. 2002, 2007; Rosel et al. 1999) were delineated primarily on the 

basis of mitochondrial DNA (mtDNA) control region sequence data. In these cases, statistically significant 

differences in haplotype frequencies were used to delineate stocks. Samples were usually from a period 

of less than a decade. The argument for demographic independence was that the mtDNA results 

indicated female philopatry to a locale, which would mean that recovery of a local population would 

depend on the number of females in that area regardless of male dispersal. 

Example: North Atlantic humpback whale stock structure

Humpback whale (Megaptera novaeangliae) stock structure in the North Atlantic was revised in 2000 to 

reflect strong fidelity to summer feeding grounds. The original Western North Atlantic stock, first 

delineated in 1995, was revised to recognize a more geographically limited Gulf of Maine stock. While 

whales using the Gulf of Maine feeding area, as well as those using other feeding areas in the North 

Atlantic, belong to a much larger group that breeds in the western Caribbean Sea (Palsbøll et al. 1997, 

2001), calves learn their migratory route and feeding ground from their mothers and photographicidentification has shown high fidelity to feeding grounds. There are frequency differences in mtDNA 

between the animals using the feeding grounds in the North Atlantic but no nuclear DNA differences 

between most of the North Atlantic feeding grounds (those whose members breed in the western 
9

Caribbean). Thus, the mtDNA reflects the demographic independence of the feeding ground 

populations. 

Example: North Pacific gray whale stock structure

Another potentially relevant case relates to gray whale stock structure, which includes a case where 

uncertainty about the magnitude of internal versus external recruitment was addressed using 

Structured Expert Decision Making (SEDM). A task force was convened to consider all the lines of 

evidence relating to three potential gray whale (Eschrichtius robustus) stocks in the North Pacific: 

whales that feed off Sakhalin Island (known as western North Pacific gray whales), whales that feed 

from central California to Southeast Alaska (commonly known as the Pacific Coast Feeding Group, or 

PCFG), and the remaining gray whales that feed elsewhere in Alaska and northeastern Russia (commonly 

known as eastern North Pacific gray whales). Western North Pacific gray whales differ from eastern 

North Pacific gray whales both in mtDNA and nuclear DNA (LeDuc et al. 2002) and the task force

concluded that these animals should constitute separate stocks under the MMPA (Weller et al. 2013). 

The task force was not able to determine whether the PCFG met the definition of stock under the 

MMPA. The PCFG differs from the eastern North Pacific stock in frequencies of mtDNA but not in 

nuclear markers. These frequency differences are relatively small and simulations suggested that the 

magnitude of these differences was compatible with internal and external recruitment at similar levels 

(Lang et al. 2011). The task force report states: “Presently, both the photo-identification and genetics 

data indicate that the levels of internal versus external recruitment are comparable, but these are not 

quantified well enough to determine if the population dynamics of the PCFG are more a consequence of 

births and deaths within the group (internal dynamics) rather than related to immigration and/or 

emigration (external dynamics).” Because of the uncertainties in interpreting the genetic and photoidentification data, the task force employed SEDM to express the differences in interpretation held by 

different members. The team was evenly divided on whether the PCFG merited being a stock because 

data indicated that it is a borderline case with respect to whether recruitment is more from internal or 

external recruitment (Weller et al. 2013).

Example: Beluga whale stock delineation in Alaska

Five beluga stocks are delineated in Alaskan waters based on genetic evidence, discontinuous summer 

distributions, and distinct population trends exhibited in different regions (Allen and Angliss 2015). The 

original inference that these qualify as stocks was based on Traditional Ecological Knowledge from 

Alaska Natives and on scientific analyses of summer distributions and spring and fall migrations (Seaman 

et al. 1985; Frost and Lowry 1990; Withrow et al. 1994). This inference has since been strengthened by 

genetic comparisons (O’Corry-Crowe et al. 1997). The five stocks are Cook Inlet, Bristol Bay, Eastern 

Bering Sea, Eastern Chukchi Sea, and Beaufort Sea (Figure 4). The beluga whales of the Cook Inlet stock 

remain within Cook Inlet throughout the year (Hobbs et al. 2005). A small population of around 20 

beluga whales of unknown origin resides in Yakutat Bay (O’Corry-Crowe 2007) and is included in the 

Cook Inlet stock. While the Cook Inlet Stock is separated from the other four stocks by the physical 

barrier of the Alaska Peninsula, the four western stocks were thought to all winter in the Bering Sea. 
10

Figure 4. Approximate distribution of beluga whales in Alaska waters. The dark shading displays the summer 

distribution of the five stocks. Winter distributions are depicted with lighter shading. Source: Angliss and Allen 

(2015).

O’Corry-Crowe et al. (1997) used mtDNA to delineate five stocks within Alaska waters using samples 

collected primarily by hunters. The stocks were differentiated by frequency differences of mitochondrial 

haplotypes with a few haplotypes found across the range but some haplotypes found only in a single 

stock. Some of those “unique” haplotypes were found in relatively high frequencies within a stock. 

These frequency differences resulted in very high probabilities that the stocks were genetically distinct. 

The frequency differences in Alaska were similar to the findings of frequency differences among the 

bays within the Sea of Okhotsk (Shpak et al. 2011). O’Corry-Crowe et al. (1997) also examined 

differences by age and sex categories and found that while the differences between older males were 

significant, they were not as great as immature males or females, suggesting that there may be a low 

level of male-mediated gene flow among the populations that winter in the Bering Sea. 

4.1.3 International Whaling Commission beluga whale stock delineation

In 1999, the IWC discussed what constituted a stock or management unit of beluga whales (white 

whales). The IWC’s Sub-Committee on Small Cetaceans agreed that management units should be 

established with the goal of maintaining beluga whales throughout the full extent of their historical 

range (IWC Report of the Sub-Committee on Small Cetaceans, 2000). The Sub-Committee agreed to 

apply a precautionary approach and started from the assumption that estuarine groups are separate 

stocks unless they are shown to be otherwise. On that basis, the Sub-Committee recognized the 

Sakhalin-Amur beluga whales as a stock (IWC Report of the Sub-Committee on Small Cetaceans 2000). 

4.1.4 International Union for Conservation of Nature (IUCN) beluga whale stock delineation

The IUCN convened a panel in 2011 to review the results of research on belugas in the Sakhalin Bay–

Amur River region of eastern Russia and to consider whether the commercial removal of beluga whales 
11

from the Sakhalin Bay-Amur River area was sustainable (Reeves et al. 2011). The panel considered 

evidence relating to whether these animals were demographically independent from other Sea of 

Okhotsk beluga whales, and found three lines of evidence pertinent to evaluating the appropriate unit 

to conserve to meet the stated goal of the Beluga Project 4

, “to estimate the sustainable annual quota 

from Sakhalinsky Bay.” The lines of evidence include: (1) strong site fidelity to summering areas, which is 

a learned behavior that may lead to patterns in maternally-inherited mtDNA (e.g., unique haplotypes or 

differences in haplotype frequencies); (2) direct genetic data; and (3) satellite tagging data. Based on 

evaluation of these lines of evidence, the IUCN panel concluded that there are several credible options 

for stock boundary delineation for a Sakhalin-Amur stock, including (a) Sakhalinsky Bay, the Amur 

region, and the southeastern Shantar region (the largest option); (b) between Chkalov Island and Zotov 

Bank (the smallest option), reflecting the area used by tagged whales during the live-capture season; or 

(c) Sakhalinsky Bay (including Zotov Bank and Baikal Bay) and the Amur estuary and river. The panel 

considered option (c) to be the preferred hypothesis.

4.2. Response to petition - review of stock structure

At the broadest geographic scale in the Sea of Okhotsk, there is strong evidence for genetic 

differentiation, at both mtDNA and nuclear DNA, between beluga whales that summer in the 

northeastern Sea of Okhotsk off the west Kamchatka coast (east of 145° E longitude) and those that 

summer in the western Sea of Okhotsk from Sakhalin Bay to Udskaya Bay, west of 145° E longitude 

(Meschersky et al. 2013). Since this petition involves individuals in the western aggregations, the Team 

agreed that the northeastern aggregations need no further consideration in this status review as they 

are clearly distinct from the beluga whales in the western Sea of Okhotsk. 

The Team identified two stock structure questions relevant to addressing the petition: 1) Are beluga 

whales that summer in the Sakhalin Bay-Amur River region demographically independent from beluga 

whales summering in the rest of the western Sea of Okhotsk? And, if so, 2) what are the geographic 

boundaries of the stock? Two lines of evidence were considered to answer these questions: 1) genetic 

comparisons among the summering aggregations in the western Okhotsk; and 2) movement data 

collected using satellite transmitters. 

4.2.1 Rationale for demographic independence of Sakhalin Bay-Amur River beluga whales

Genetic Data

A variety of genetic studies have been performed on beluga whales from the western Sea of Okhotsk 

(Meschersky et al. 2008, 2013; Meschersky and Yazykova 2012). The first step in considering the 

strength of these genetic data is to consider whether the samples adequately represent a random 

selection of the population(s) in question to determine whether the sampling could result in a false 

positive (finding difference between the aggregations when there was none). In these studies, 107

individuals have been sampled from the Sakhalin Bay-Amur River area over seven sampling years with 

relatively even sampling per year and an overall relatively even split between males (57) and females 

(50). However, Meschersky et al. (2013) suggested that there was a duplicate sample so we considered

 4 The “Beluga Project” refers to the review undertaken by the IUCN Panel (Reeves et al. 2011).
12

the correct number to be 106. This sampling is fairly robust and likely sufficiently representative of the 

haplotypic frequency distribution of the full population. Sampling from the four other bays in the 

western Sea of Okhotsk (Nikolaya, Ulbansky, Tugursky, and Udskaya) has been less thorough, most of it 

having been conducted in a single year and the samples from all four bays are skewed towards males

(Meschersky et al. 2013). The IUCN panel expressed concerns over this sampling (see above). The 

sample size from Nikolaya Bay is particularly small, making it difficult to draw conclusions about the 

relationship of whales in this bay to the other bays based on genetic data. 

The genetic comparisons between samples from the beluga whales of the Sakhalin Bay-Amur River and 

the beluga whales of the other bays consistently found significant differentiation in mtDNA haplotype 

frequencies among bays (Meshersky et al. 2013). As in the Alaska example, in some cases haplotypes 

were found that were unique to a bay, indicating that most recruitment is internal. For example, 

although the most common haplotype is the same in both Sakhalin (found in 37 of 106 animals sampled)

and Udskaya Bays (19 of 46 animals sampled), the second and third most common haplotypes in 

Sakhalin Bay (27 and 17 of 106 animals sampled) were not found in Udskaya Bay (0 and 0 of 46 animals 

sampled), nor anywhere else that was sampled, and the second and third most common haplotypes that 

are present in Udskaya Bay (16 and 6 of 46) were each found in only a single individual in Sakhalin Bay (1 

and 1 of 106) (Meschersky et al. 2013). Significant differentiation was also found between Sakhalin and 

Ulbansky Bays and Sakhalin and Tugursky Bays, but not between Sakhalin Bay and the adjacent Nikolaya 

Bay, though the small sample size may have played a role in the latter comparison (Meschersky 2012). 

Although the sampling in Udskaya, Tugursky, and Ulbansky Bays is not optimal, frequency differences 

are so strong as to be unlikely to have come from a biased sample of a large, panmictic western Sea of 

Okhotsk aggregation. The bias towards males in the other bays also lessens the chance that a 

disproportionate number of samples came from mothers and offspring (which would have the same 

mtDNA haplotype). The presence of some common haplotypes across bays suggests there may be some 

external recruitment or, alternatively, founding events have been recent enough that there has not 

been sufficient time for lineage sorting amongst the bays, resulting in some common haplotypes over 

large geographic ranges. 

Analysis of nuclear microsatellite markers found no evidence for genetic differentiation among the bays 

of the western Sea of Okhotsk with the exception of a comparison of Sakhalin Bay to the distant 

Ulbansky Bay (Meschersky 2012; Meschersky et al. 2013). This negative finding for differentiation in 

nuclear DNA does not rule out that beluga whales in these different summer feeding areas could 

constitute stocks under the MMPA (see harbor seal, harbor porpoise, and humpback examples above). 

The mtDNA differences alone are sufficient evidence for demographic independence. 

Telemetry Data

Though sparse, telemetry data from satellite tags support the conclusions drawn from the genetic data. 

From 2007-2010, 22 beluga whales were tagged at Sakhalin Bay. Tags transmitted for 2.5-9.5 months, 

with an average of six months. Most whales stayed close to the tagging site in summer (Shpak et al. 

2010), though several tagged whales were sighted in Nikolaya Bay in summer (Shpak et al. 2011). Ten 

whales tagged in 2010 moved in the fall to Nikolaya Bay and the eastern Shantar region and four went 

as far as Ulbansky Bay, spending up to three months in these areas. In winter, tagged whales moved 
13

north and west into offshore waters (Shpak et al. 2012). Though not very many whales have been 

tagged, the data available to date suggest whales present in the summer in Sakhalin Bay also use 

Nikolaya Bay, but there is little evidence for movement between Sakhalin Bay and the other bays further 

to the west during spring and summer. 

Geographical and Ecological Separation 

Beluga whales in other better-studied areas form strong social groups that follow learned, predictable 

annual movements between breeding and feeding areas. Summer aggregations often focus on 

seasonally available fish runs, like salmon runs (Melnikov 1999). Site fidelity to summer feeding areas is 

not uncommon in cetaceans and can often result in genetic differentiation in mtDNA (see humpback 

whale example above; Palsbøll et al. 1997, 2001). In some cases, site fidelity is strong enough and 

occurs over a long enough time period that mtDNA lineage sorting can occur, resulting in mtDNA 

haplotypes unique to a given feeding area. Additional examples of the long-term nature and isolation of 

these aggregations are cases of several rivers in eastern Hudson Bay and Ungava Bay, Canada where 

beluga whales were locally hunted to low levels and have not rebounded or been recolonized from 

other populations (Reeves and Mitchell 1987a,b; Kingsley 2000; Hammill et al. 2004). A population in 

Alaska found in the Kuskokwim River delta that was also hunted to very low levels in the 1950s has not 

recovered (pers. com. John Burns). 

Figure 5. Map of Alaska beluga whale areas

Sakhalin Bay-Amur River beluga whales exhibit behaviors and frequency differences in mtDNA 

haplotypes (see above) consistent with the general beluga whale life history strategy seen in Alaska, and 

therefore would be similar to aggregations defined as stocks within Alaska. The two Alaska beluga 

stocks with movements and seasonal cycles most similar to the Sakhalin Bay-Amur River beluga whales 
14

are the Eastern Bering Sea stock and the Bristol Bay stock (Figure 5). The Eastern Bering Sea beluga 

whales spend summers feeding on salmon runs in the Yukon River delta, in Norton Sound and south 

along the coast as far as Scammon Bay, and are occasionally found many miles upstream from the 

mouth of the river. In the winter these belugas move offshore into the Bering Sea and south along the 

coast to Kuskokwim Bay and east of Cape Newenham (Lowry et al. 1999; Angliss and Allen 2015; ABWC 

unpublished data 5

). The Bristol Bay beluga stock spends its summers feeding on salmon runs in 

Nushagak Bay, Kvichak Bay and the tributaries to the estuaries. In the winter the Bristol Bay beluga 

whales move into deeper, partially ice-covered waters south and east of Cape Constantine (Frost and 

Lowry 1990; Angliss and Allen 2015; NMFS, ADFG unpublished data 6

) 

Together genetic and movement data indicate that beluga whales in the western Sea of Okhotsk exhibit 

life history characteristics and levels of differentiation very similar to beluga whales in Alaska that have 

been designated as stocks. Genetic mtDNA differentiation among the bays and evidence for limited 

movement into Nikolaya and Ulbansky Bays strongly suggest the Sakhalin Bay-Amur River aggregation of 

beluga whales represent a stock as defined under the MMPA, and limits the discussion of boundaries to 

whether the belugas in Nikolaya Bay or Ulbansky Bay should be included. 

4.2.2 Rationale against demographic independence of Sakhalin Bay-Amur-River beluga whales

The primary rationale against separating the Sakhalin Bay-Amur-River beluga whales from beluga whales 

in bays further west is that the genetic sampling in the other bays is concentrated in one or two years 

and is skewed towards males, allowing potential for a false positive finding. In addition, there are no 

long-term data to allow interpretation of the temporal stability of the mtDNA haplotype frequency 

differences. Finally, the lack of nuclear DNA (microsatellite) differentiation among most summer 

feeding areas in the western Sea of Okhotsk (the exception being between Sakhalin Bay-Amur River and 

Ulbansky Bay) is consistent with interbreeding between animals that aggregate in Sakhalin Bay and the 

other bays. Because these animals spend some parts of the year together (i.e., winter), it is plausible 

that recruitment into a summer aggregation could be both internal and external. However, the nuclear

data available to date are too weak, given the level of and design of the sampling, to assess how much 

internal versus external recruitment there is.

The satellite tag data indicated that some whales captured and tagged in Sakhalin Bay in mid-summer

entered Nikolaya Bay in the fall. Four whales tagged in Sakhalin Bay in summer visited Ulbansky Bay in 

the fall (Shpak et al. 2011), suggesting some Sakhalin whales may move to bays to the west before 

moving off shore in the winter. However, since these movements took place in the fall and breeding 

occurs in the spring, these movements likely represent seasonal migratory pathways rather than mixing 

of breeding stocks. In addition, those satellite-tagged individuals that transmitted into the winter 

 5 Maps and description available at http://www.north-slope.org/departments/wildlife-management/comanagement-organizations/alaska-beluga-whale-committee/abwc-research-projects/eastern-bering-sea-stockprojects

6 Maps and description available at http://www.north-slope.org/departments/wildlife-management/comanagement-organizations/alaska-beluga-whale-committee/abwc-research-projects/bristol-bay-stock-projects
15

months were tracked to the central and northern Sea of Okhotsk. Thus, contact and interbreeding 

among belugas from different summering areas may occur offshore in the spring before they return to 

the summer grounds.

Finally, because the area concerned is relatively small and has no significant barriers to movement, it is 

reasonable to assume that a local extirpation would eventually be recolonized by beluga whales from 

one of the other bays. However, there are no direct data to support this, and examples of removals in 

Alaska suggest recolonization would be unlikely in a single generation.

4.3 Conclusion about demographic independence

4.3.1 Structured Expert Decision Making

When data are either not available or not clearly conclusive, a method called Structured Expert Decision 

Making (SEDM) is sometimes employed as a means to elicit expert opinion while also characterizing

uncertainty within the expert opinion. In some NMFS Endangered Species Act status reviews, Biological 

Review Teams (BRTs) have adopted formal methods, such as SEDM, to express plausibility for use in 

guiding its analysis of Distinct Population Segments (DPS) and in assessing the risks to the population(s). 

This method has also been referred to as the “FEMAT” method because it is a variation of a method 

used by scientific teams evaluating options under the Northwest Forest Plan (Forest Ecosystem 

Management Assessment Team). Under SEDM, each expert is asked to distribute plausibility points 

among the choices/scenarios for a given statement reflecting his or her opinion of how likely that choice 

or option correctly reflected the population status. If the expert is certain of a particular option, or feels 

it is the only plausible scenario, he or she could assign all points to that option. An expert with less 

certainty about which option best reflected reality, or best reflected the population’s status, could split 

the points among two or more options. This method has been used in all status review updates for 

anadromous Pacific salmonids since 1999 (Good et al. 2005), as well as in reviews of Southern Resident 

killer whales (Orcinus orca), West Coast rockfishes, Pacific herring (Clupea pallasii), Pacific groundfish, 

North American green sturgeon (Acipenser medirostris), black abalone (Haliotis cracherodii), Hawaii false 

killer whales (Pseudorca crassidens), and humpback whales (Megaptera novaeangliae).

In the humpback whale status review (Bettridge et al. 2015), BRT members distributed 100 likelihood 

points among the defined scenarios or options, reflecting their expert opinion of the relative likelihood 

that the status of a specific DPS fell into each of three risk categories. Then the team discussed how they 

had allocated points and subsequently had a chance to revise their scores. 

In the Hawaii false killer whale status review (Oleson et al. 2010), BRT members distributed ten points 

between the arguments for and against each question where there was uncertainty. Team members 

agreed to view resulting scores with names associated to facilitate discussion and assure that semantic 

uncertainty was not responsible for any disparate votes. The BRT discussed the scores and, in some 

cases, members adjusted scores when prior articulation of the arguments had been unclear. 

SEDM was also used by a task force considering whether the Pacific Coast Feeding Aggregation of gray 

whales constituted a stock under the MMPA (Weller et al. 2013). For some questions, the experts 

distributed 100 points among five options (strongly agree, strongly disagree, neutral, somewhat 

disagree and strongly disagree) for each question. After completing this SEDM exercise, the task force
16

concluded that the format of questions running from strongly agree to strongly disagree was not 

optimal because it had to be clarified in the text whether “disagreement” was because the data were 

uncertain or whether the case was borderline. 

4.3.2 Beluga Whale Status Review Team SEDM 

Because of the limited evidence available regarding the stock structure of the Sakhalin Bay-Amur River 

beluga whales relative to other western Sea of Okhotsk beluga whales, the Team used SEDM procedures 

to evaluate the available genetic and telemetry data for beluga whales in the western Sea of Okhotsk as 

they relate to delineating stocks. Learning from the gray whale lesson, this beluga status review team

decided on a different formulation of questions for the stock delineation exercise. For each question, 

each of the ten Team members assigned 100 plausibility points across multiple statements that spanned 

what was felt to be plausible for the question. The Team agreed that members should allocate points 

evenly across all possible statements for a given question if they felt the available data were insufficient 

to address the statement. Scores were then averaged to produce a single score for each statement.

It took several rounds of discussion to get the wording of the questions and associated statements to 

the point where all experts understood and agreed on the meaning/intent of each statement. The Team

considered eight questions: three that pertained to how similar Sea of Okhotsk beluga whales were to 

Alaska beluga whales (to give insight to how evidence used to delineate stocks within Alaska could be 

used by analogy in the Sea of Okhotsk), four that pertained to different lines of evidence about the 

demographic independence of Sakhalin Bay-Amur River beluga whales with respect to beluga whales 

elsewhere in the western Sea of Okhotsk, and a final statement that pertained to the plausibility of 

demographic independence of Sakhalin Bay/Amur-River beluga whales when all lines of evidence were 

taken together.

Responses to questions concerning similarities between Alaska and Okhotsk beluga whales

Question 1. Allot plausibility points to the following statements considering DNA evidence: 

Option AVG

The pattern of differentiation in mtDNA observed among beluga whales in 

areas within the western Sea of Okhotsk is similar to the pattern observed in 

beluga whale aggregations defined as the Bristol Bay and Norton Sound stocks 

within Alaska

82.5

The pattern of differentiation in mtDNA observed in beluga whales among 

areas within the western Sea of Okhotsk is not similar to the pattern observed 

in beluga whale aggregations defined as the Bristol Bay and Norton Sound 

stocks within Alaska

17.5

Interpretation: There was a high level of agreement that the pattern of mtDNA differentiation observed 

among beluga whales in the western Sea of Okhotsk is similar to that seen in beluga whale stocks 

delineated in Alaska (82.5% agreement with no expert strongly supporting the alternative). The Team

agreed the term “pattern” did not refer to the magnitude of genetic differentiation, which depends on 
17

effective population size, but rather meant finding strong statistical frequency differences between the 

strata. Bristol Bay and Norton Sound were chosen to be most similar to the western Sea of Okhotsk with 

respect to geography and behavior.

Question 2. Allot plausibility points to the following statements considering evidence about movement 

patterns including summer site fidelity: 

Option AVG

Movement patterns observed in the western Sea of Okhotsk are similar to 

movement patterns observed in beluga whale aggregations defined as stocks 

within Alaska

80.0

Movement patterns observed in the western Sea of Okhotsk are not similar to 

patterns observed in beluga whale aggregations defined as stocks within 

Alaska

20.0

Interpretation: There was a high level of agreement that telemetry-based movement patterns observed 

in western Sea of Okhotsk beluga whales are similar to movement patterns observed in beluga whale 

aggregations defined as stocks within Alaska (80.0% agreement with no expert strongly supporting the 

alternative). 

Question 3. Allot plausibility points to the following statements considering the cumulative evidence 

from questions 1 and 2 about the similarity of western Sea of Okhotsk beluga whales to stocks of beluga 

whales in Alaska: 

Option AVG

The overall mtDNA and movements data observed in western Sea of Okhotsk 

beluga whales are similar to mtDNA and movements data observed in beluga 

whale aggregations defined as stocks within Alaska such that they can be 

considered analogous

83.1

The overall mtDNA and movements data observed in western Sea of Okhotsk 

beluga whales are not similar to mtDNA and movements data observed in 

beluga whale aggregations defined as stocks within Alaska such that they 

cannot be considered analogous

16.9

Interpretation: There was a high level of agreement that both mtDNA data and studies of movements 

of beluga whales in the western Sea of Okhotsk are similar to the finding of similar studies of mtDNA 

and movements conducted on beluga whale aggregations defined as stocks within Alaska such that they 

can be considered analogous (83.1% agreement with no expert strongly supporting the alternative). 
18

Responses to questions regarding the support of separate lines of evidence for alternative areas 

that delimit the stock to which Sakhalin Bay-Amur River beluga whales belong

Question 4. Allot plausibility points to the following statements considering mtDNA evidence: 

Option AVG

Beluga whales in Sakhalin Bay-Amur River are demographically independent 

from other western Sea of Okhotsk beluga whales

54.4

Beluga whales in Sakhalin Bay-Amur River and Nikolaya Bay together are 

demographically independent from other western Sea of Okhotsk beluga 

whales

39.4

Beluga whales in Sakhalin Bay-Amur River, Nikolaya Bay, and Ulbansky Bay 

together are demographically independent from other western Sea of 

Okhotsk beluga whales

4.4

There are no demographically independent groups within the western Sea of 

Okhotsk (i.e., the western Sea of Okhotsk is one demographically 

independent population)

1.9

Interpretation: There was strong agreement that the mtDNA evidence suggests there are multiple 

demographically independent populations of beluga whales in the western Sea of Okhotsk and that 

Sakhalin Bay-Amur River beluga whales are demographically independent from beluga whales in 

Ulbansky Bay and the bays to the west. Members were less certain whether Sakhalin Bay-Amur River 

beluga whales belong to a stock that summers only in the Sakhalin Bay-Amur River region or in a larger 

area that includes Nikolaya Bay.

Question 5. Allot plausibility points to the following statements considering evidence about nuclear 

DNA: 

Option AVG

There is complete random mating within beluga whales in the western Sea of 

Okhotsk

25.4

There could be some non-random mating within the western Sea of Okhotsk 

that is either too recent or at too low a level to be detected given current 

sample sizes and marker numbers

52.9

Sakhalin Bay-Amur River beluga whales mate primarily with each other 21.8

Interpretation: Conclusions concerning demographic independence among locations with the western 

Sea of Okhotsk that could be drawn from nuclear DNA evidence were less certain overall, with the 

greatest support (53%) for the potential for some non-random mating within the western Sea of 
19

Okhotsk. The remaining points were split roughly equally between the other two statements. Overall, 

the Team expressed uncertainty with this statement due to concerns about the adequacy of the 

sampling and markers used in the nuclear DNA studies completed at the time. 

Question 6. Allot plausibility points to the following statements considering all genetic evidence: 

Option AVG

Sakhalin Bay-Amur River is a demographically independent population 46.9

Sakhalin Bay-Amur River and Nikolaya Bay together are a demographically 

independent population

44.4

Sakhalin Bay-Amur River, Nikolaya Bay, and Ulbansky Bay together are a 

demographically independent population

6.9

There are no demographically independent groups within the western Sea of 

Okhotsk (i.e., the western Sea of Okhotsk is one demographically 

independent population)

1.9

Interpretation: There was strong agreement that the genetic evidence does not support that the 

Sakhalin Bay-Amur River beluga whales are members of the same stock as those found in Ulbansky Bay. 

There was very little support for there being no demographically independent populations within the 

western Sea of Okhotsk. There was nearly equal support for Sakhalin Bay-Amur River either being

demographically independent alone or being part of a slightly larger demographically independent 

population that includes Nikolaya Bay.

Question 7. Allot plausibility points to the following statements considering only telemetry evidence: 

Option AVG

Sakhalin Bay-Amur River is demographically independent from other western 

Sea of Okhotsk beluga whales

23.8

Sakhalin Bay-Amur River and Nikolaya Bay together are demographically 

independent from other western Sea of Okhotsk beluga whales

32.5

Sakhalin Bay-Amur River, Nikolaya Bay, and Ulbansky Bay together are 

demographically independent from other western Sea of Okhotsk beluga 

whales

23.1

There are no demographically independent populations within the western 

Sea of Okhotsk (the western Sea of Okhotsk is one demographically 

independent population)

18.1

Interpretation: The relatively even allotment of points across options indicated that experts felt the 

telemetry data were relatively weak in addressing stock delineation questions. During discussion of this 
20

question, there was some disagreement resulting from different members’ interpretations of telemetry 

data. Some felt that since the telemetry data revealed that animals tagged within the Sakhalin BayAmur River generally stayed close to that area there was sufficient information to draw conclusions 

about demographic independence. Others felt that in general the telemetry data were weak because 

there is no way to distinguish between internal and external recruitment based on movements of 

animals already recruited to a feeding group.

Stock delineation question based on all lines of evidence

Question 8. Allot plausibility points to the following statements considering all evidence: 

Option AVG

Sakhalin Bay-Amur River is a demographically independent population 44.4

Sakhalin Bay-Amur River and Nikolaya Bay together are a demographically 

independent population

42.5

Sakhalin Bay-Amur River, Nikolaya Bay and Ulbansky Bay together are a 

demographically independent population

11.9

There are no demographically independent groups within the western Sea of 

Okhotsk (the western Sea of Okhotsk is one demographically independent 

population)

1.3

Interpretation: There was strong agreement that the genetic evidence does not support that the 

Sakhalin Bay-Amur River beluga whales are members of the same stock as those found in Ulbansky Bay. 

There was very little support for there being no demographically independent groups within the western 

Sea of Okhotsk. Although there is more support for Sakhalin Bay-Amur River beluga whales belonging to 

a stock that summers only in that region, there is nearly equal support for Sakhalin Bay-Amur River 

belugas being part of a slightly larger demographically independent population that also includes 

Nikolaya Bay.

4.3.3 Structured Expert Decision Making Summary

The experts were largely in agreement that Sakhalin Bay-Amur River beluga whales were either their 

own stock or belonged to a stock that also included whales that summer in Nikolaya Bay. These results 

were largely based on mtDNA evidence as the allocation of points was very similar between the mtDNA 

evidence alone and all evidence taken together. The experts also strongly supported that both 

movements and mtDNA patterns were analogous between stocks of beluga whales in Alaska and 

belugas within the western Sea of Okhotsk.
21

5. Response to petition - Estimation of depletion level for Sakhalin Bay-Amur River 

belugas 

As described above, the Team concluded that Sakhalin Bay-Amur River beluga whales do represent a 

demographically independent population and have characteristics similar to beluga whale stocks in 

Alaska. Therefore, the second question to be analyzed by the Team was whether the stock is depleted.

5.1 Back calculation of carrying capacity

Management objectives under the MMPA are intended to maintain marine mammal populations within 

their OSP ranges or, if the population is below the lower bound of OSP, to recover to OSP in a 

reasonable length of time. NOAA has defined OSP as a population size that falls within a range from the 

population level of a given species or stock that is the largest supportable within the ecosystem (i.e., 

carrying capacity, or K) to its MNPL. Historically, MNPL has been expressed as a range of values 

between 50 and 70 percent of K. To determine a population’s depletion level, or abundance relative to 

K, we need to have an idea of historical K. K, the equilibrium population level before impact by man 

(direct or indirect), can be difficult to measure. One technique employed by NMFS has been the backcalculation method, which assumes that the historical population was at equilibrium, and that the 

environment has not changed greatly. The approach of back-calculation is to look at the current 

population and then calculate historical carrying capacity based on how much the population has been 

reduced by human actions.

NMFS applied this approach in the management of the subsistence hunt of the Cook Inlet beluga whale 

stock (73 FR 60976, October 15, 2008). The Cook Inlet beluga whale depletion level was estimated using 

a back calculation of carrying capacity. In 1998, Cook Inlet beluga whales were determined to be 

depleted when the population had fallen from an estimated 653 animals in 1994 to 347 animals in 1998. 

In 1999, a moratorium on the hunt was implemented until a co-management plan could be developed. 

The harvest plan developed under the co-management agreement only allowed a subsistence hunt if it 

would allow the stock to recover to OSP in 100 years with 95% confidence. Carrying capacity (K) for the 

Cook Inlet Beluga whale stock was determined to be 1,300 whales in 1979 (Calkins 1984) and the lower 

limit of OSP was set at 60% of K, or 780 belugas. 

5.2 Application of back-calculation to Sakhalin Bay–Amur River beluga whales

The available data for the Sakhalin Bay-Amur River stock of beluga whales are a time series since 1915

(Shpak et al. 2011) of hunt and live-capture for display data and an estimate of abundance in 2009-2010 

(Reeves et al. 2011). These data, plus an estimate of the stock’s productivity, allow back-calculation of 

the historical stock size (i.e., K) that probably existed prior to the beginning of the catch history. It was 

not feasible to develop an estimate of any additional anthropogenic mortality on this stock. 

A population model was used to perform these calculations. In short, for each year, the model 

calculates the expected number of animals added to the stock by natural population growth and it 

subtracts the number removed by the hunts, and then the model grows or shrinks the population for 

the next year according to the difference between the growth and the removals. A computer 

spreadsheet search routine finds the value of K that is large enough to have accommodated the 
22

removals and low enough to have resulted in a population in 2009-2010 that matches the observed 

abundance in those years. 

The population equation is Nt+1 = Nt(1+r(1- (Nt/K)z)-Ht where:

Nt is the population size in year t,

r is the annual rate of increase (productivity) when the population is small,

K is the carrying capacity,

z controls the rate at which productivity declines as Nt approaches K, and

Ht is the removals in year t.

The values of r and z have not been measured for Sakhalin Bay-Amur River beluga whales so values 

(r=0.04 and z=2.39) are used in the “base case.” The value for r= 0.04 is a default value for cetaceans 

used in PBR calculations (NMFS 2005), and z=2.39 is in the middle of the range considered reasonable 

for cetaceans (Breiwick and York 2009). Alternate plausible values for r and z were also evaluated to 

test the model’s sensitivity to changes in these parameters.

Once the back-calculation estimated the value of K that resulted in the estimated population size in 

2009-2010, the population model was projected forward to 2015 to estimate the current population 

size. The current depletion level was then calculated by dividing the 2015 stock size (estimated by the 

model) by the estimated carrying capacity (K). 

5.2.1 Data Input: Catch History 

Commercial hunts of the Sakhalin Bay-Amur River beluga whale population began in 1915 (Shpak et al. 

2011) and subsistence hunts have occurred prior to, during, and since this date (Appendix). The largest 

commercial hunts occurred in 1927-1934 with a peak recorded catch of 2,817 in 1933, and then declined 

substantially. Shpak et al. (2011) indicate that the focus of the commercial catch moved to other areas 

of the Sea of Okhotsk after the 1930s, suggesting that the Sakhalin Bay-Amur River population was 

sufficiently depleted that catch rates had declined. There are a number of years with known but poorly 

documented hunts, and years for which more than one estimate is provided. A complete catch history 

is required to estimate carrying capacity by the back-calculation method, so two options were

considered: a “high take” and a “low take” scenario. The high take scenario gives a conservative 

estimate of depletion, because higher take results in a higher estimated historic K and a more depleted 

current population relative to K (i.e., lower percentage of K). The low take scenario uses what is thought 

to be the lowest take possible and provide a minimum estimate for K, resulting in a less depleted 

current population relative to K (i.e., higher percentage of K). The low take scenario thus provides an 

upper bound for the population’s status relative to K. Both options used the catch data from Shpak et 

al. (2011).

The low take scenario used the take estimates when they were available, and when more than one 

estimate of take was available, used the lowest value. Years with no indication that takes occurred were 

left blank and treated as zero. The low take option is included to evaluate whether this unlikely scenario 

would still result in a depleted population. 
23

The high take scenario used the take estimates where they were available, and when more than one 

estimate of take was available, used the highest value. For years when hunts are thought to have 

occurred but no record is available, missing values were estimated or interpolated from adjacent years 

with similar hunts. The high take scenario is considered the better of the two because it accounts for 

times when takes are known to have occurred but are not documented. Additionally, we did not 

account for beluga whales that are struck and lost because these data are not available, so the high take 

option may even be an underestimate.

Large-scale beluga whale harvests in the Sakhalin Bay-Amur River began in 1915. Prior to that the 

subsistence hunt in the Sakhalin Bay-Amur River was estimated at between five and 30 animals per year 

in the 1800s (Shpak et al. 2011); these values were used for the low take and high take scenario, 

respectively. The subsistence hunt is thought to have existed for many years prior to 1915 (Shpak et al. 

2011), so the population was already reduced somewhat below its pristine carrying capacity by 1915. 

This is accounted for in the back-calculation by running the model for 100 years (1815-1915) with a take 

of five or 30 animals per year. This reduces the population estimate by less than 0.5% prior to onset of 

the directed commercial hunt.

While commercial catch data are available for the period 1915-1919, the Team found no such data for 

the period 1919-1924. Missing data could indicate that no commercial catch occurred due to military 

activity (low take scenario), or commercial catches may have continued but were unreported (high take 

scenario, estimated as the average of catch in 1918 and 1925). Furthermore, no catch was reported in 

1931 and 1932; therefore the low take scenario for these years is zero and the high take scenario is the 

average of reported takes in 1930 and 1933. Starting in 1938 to 1986, there are no records of 

commercial takes in the Sakhalin Bay-Amur River until 1986, when captures for live display began. 

During the period 1938 to 1955, no commercial takes are reported but Shpak et al. (2011) indicates that 

unofficial sources reported that some commercial takes occurred during this period. From 1956 through 

1959, takes for the entire Okhotsk Sea are estimated to be 800 annually but these are thought to have 

come largely from the large bays to the west of Sakhalin Bay-Amur River. Thus, for 1938-1959 we use 

zero for the low take and set the high take scenario at 100 per year to account for possible takes from 

the Sakhalin Bay-Amur River. After 1960, the commercial take of belugas throughout the Okhotsk Sea 

had ended (Shpak et al. 2011), so both the low and high options are zero during 1960-1985. In 1986, live 

capture removals began (Fisher and Reeves 2005). However, there are no take records for the period 

1986-1999, so the Team used the average of takes reported during 2000-2012 for the high take scenario

and zero for the low take scenario. This average is also used for the high take scenario in 2013 and 

2014, and zero for the low take scenario because records are not yet available.

5.2.2 Data Input: 2009-2010 Abundance Estimate 

The most recent estimate of abundance, 3,961, is based on aerial surveys done in 2009 and 2010

(Reeves et al. 2011). The Team used abundance estimates from only the Sakhalin Bay–Amur River area 

because there was no current abundance estimate of the Nikolaya Bay region, but few animals are 

thought to be in Nikolaya Bay in the survey period compared to the Sakhalin Bay-Amur River, so the

estimate accounts for nearly all of the population (Shpak et al. 2011). The estimate includes a correction 
24

factor, which accounts for beluga whales that were submerged during overflight and not available to be 

counted. 

5.2.3 Results: Estimated Carrying Capacity and Depletion Level

The calculated K, projected 2015 abundance, and depletion level (% of K) results are shown in Table 1. 

The table shows calculations using the high and the low catch scenarios, and it also shows the degree of 

sensitivity of the high catch option to a range of plausible values of r and z. The value of z = 1 results in a 

population model with the MNPL at 50% of K, z = 2.39 results in a model with MNPL at 60% of K, and z = 

5.04 results in a model with MNPL at 70% of K. 

Trial Catch r z K

Projected 

2015 

abundance

% of K

Sensitivity 

(% Change in K from 

Base Case)

1 

(Base) High 0.04 2.39 17,700 4,520 25.5% 0%

2 High 0.03 2.39 18,000 4,068 22.6% 2%

3 High 0.02 2.39 20,800 4,056 19.5% 18%

4 High 0.04 5.04 16,600 4,571 27.4% -6%

5 High 0.04 1 19,500 4,349 22.3% 10%

6 Low 0.04 2.39 13,200 4,626 35.0% -25%

Table 1. Estimated carrying capacity (K) and depletion levels for various model parameter sets.

We considered the value of K resulting when r = 0.04 (the default for MMPA potential biological removal 

level calculations for cetaceans; NMFS 2005), z = 2.39, and the high take scenario (which assumes some 

medium level of catch for years with missing data in which take is thought to have occurred) to be the

“base case.” 7

 Additional columns indicate the projected 2015 abundance, and the percent of K 

(depletion level) that the 2015 abundance represents. The final column shows the percentage change in

K relative to the base case. Changes in r and z (trials 2-5) resulted in only small changes in K. 

According to the base case scenario, the population in 1960 reached a minimum of 1,343 (Figure 6) 

following high historical harvests and an average take level during 1938 to 1959 of 130 animals per year. 

The back-calculation indicates that the greatest decline occurred during the 1930s due to high take 

levels and that the population may be slowly increasing at recent take levels (between 28 and 53

animals per year, of which between five and 30 are taken as subsistence). However, there is no direct 

evidence that such an increase is occurring. The current depletion level, 25.5% of K, is far below the 

stock’s OSP, which NMFS has in practice considered to be reached at a depletion level of 60% K. The 

 7 The take levels for the period 1938-1959 were set at 100 to account for possible takes; a sensitivity analysis 

(results not shown in the table) in which the take levels were increased by 100 and decreased by 100 resulted in K 

increasing and decreasing by less than 1,200 animals respectively.
25

team was concerned that for several years the commercial removals were known to have occurred but 

could only be estimated, in particular the 100 takes per year between 1938 and 1959, and considered an 

extreme example in which only the documented takes were considered. Even this optimistic scenario 

with both low commercial and subsistence catches (trial 6) results in a population at 35.0% of K, below 

OSP. Thus the team concluded that while takes were not the fully documented that it was unnecessary 

to attempt to further resolve take numbers within the range because both scenarios fell below OSP.

We described the abundance estimate of 3,961 as a conservative estimate because Nikolaya Bay was 

not included. If we add 500 to the abundance estimate to account for Nikolaya Bay and run the model 

using the base case parameters, the result is an increase of less than 100 animals in the estimate of K,

but the estimate of depletion would be 28.9% of K. Thus, having an abundance estimate for Nikolaya 

Bay would not change the estimate of K significantly; it would result in a slightly higher population 

relative to K, but the population would still be below OSP.

Figure 6. Annual estimated abundance (blue line/open circles) and annual takes (black line/red circles) from the 

base case population model. Takes peaked in 1933 when the population had already declined by > 50%. The 

population abundance reached a minimum in 1960, then slowly began to increase.

6. Summary

NMFS received a petition from the Animal Welfare Institute, Whale and Dolphin Conservation, Cetacean 

Society International, and Earth Island Institute to designate the Sakhalin Bay-Amur River beluga whales 

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

1915 1935 1955 1975 1995 2015

Total Annual Take

Population Size

Year
26

as depleted under the MMPA. The petition asserts this group of whales constitutes a stock and that this 

stock is below its OSP and qualifies for a depleted designation. NMFS found the petitioned action may 

be warranted. NMFS established a status review team (referred to as the Team), to review the status of 

the beluga whales in the Sakhalin Bay-Amur River portion of the Okhotsk Sea using the best, currently 

available information. The Team’s review involved two steps. First, to determine whether the Sakhalin 

Bay-Amur River beluga whales constitute a stock under the MMPA, and then, second, if these whales 

meet the definition of stock, determine the depletion level for the stock. In regard to the first step, the 

Team agreed that there was strong evidence for genetic differentiation within the Sea of Okhotsk in 

both mtDNA and nuclear DNA, between beluga whales that summer in the western Sea of Okhotsk from 

Sakhalin Bay to Udskaya Bay (west of 145o E longitude) and those that summer in the northeastern Sea 

of Okhotsk off the west Kamchatka coast (east of 145o E longitude). Because of the limited evidence 

regarding the stock structure of the Sakhalin Bay-Amur River relative to other western Sea of Okhotsk 

beluga whales, the Team used SEDM procedures to evaluate the available genetic and telemetry data 

for beluga whales in the western Sea of Okhotsk as they relate to delineating stocks. Using SEDM 

procedures, eight questions concerning the interpretation of the genetic (mtDNA and nuclear DNA) and 

telemetry data as well as the similarities with how beluga whale stocks in Alaska have been delineated 

were addressed. The Team concluded that the movement and mtDNA patterns of the beluga whales in 

the western Sea of Okhotsk were analogous to beluga whales in Bristol Bay and Norton Sound Alaska, 

which are defined as demographically independent stocks under the MMPA. The Team concluded that 

Sakhalin Bay-Amur River whales were either their own stock or they belonged to a stock that also 

summers in Nikolaya Bay. More genetic and tagging data would be needed to conclude more precisely 

how belugas in Nikolaya Bay relate to belugas in the Sakhalin Bay – Amur River area. 

Since the Team concluded the Sakhalin Bay-Amur River whales constitute a stock, the Team next 

addressed the question of whether the stock was depleted using time series of abundance and catch 

(commercial and subsistence) data in a back-calculation population model. The Team used the 

abundance estimates in 2009-10 from the Sakhalin-Amur River region, and developed an estimate of the 

time series of catch since 1915, including minimum and maximum scenarios for years in which catch was 

uncertain. The back-calculation investigated the sensitivities of the effects of an assumed range of 

plausible parameter values and the high and low catch estimate scenarios. In conclusion, the current 

depletion level under the high take scenario was 25.5% K and under the low take scenario was 41.7% K,

both below OSP, which is reached at a depletion level of 60% K, where K is considered the abundance in 

approximately 1914. 
27

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31

Appendix 

Table of takes used in the back calculation of carrying capacity values. Values in bold are inferred, blanks 

indicate no data. The low option uses only reported data, the high take includes estimated takes in 

some year. Years for which the low option is blank have no available reports of takes. For years with 

more than one reported value (see Shpak et al. 2011), the lowest value was used in the low option and 

the highest value was used in the high option.

Commercial hunt Subsistence hunt Total removals

Year Low High Low High Low High

1915 16 48 5 30 21 78

1916 507 507 5 30 512 537

1917 539 539 5 30 544 569

1918 3 3 5 30 8 33

1919 58 5 30 5 88

1920 58 5 30 5 88

1921 58 5 30 5 88

1922 58 5 30 5 88

1923 58 5 30 5 88

1924 58 5 30 5 88

1925 112 112 5 30 117 142

1926 241 241 5 30 246 271

1927 497 1047 5 30 502 1077

1928 1504 1504 5 30 1509 1534

1929 1749 1749 5 30 1754 1779

1930 1481 1481 5 30 1486 1511

1931 1888 5 30 5 1918

1932 1888 5 30 5 1918

1933 2817 2817 5 30 2822 2847

1934 1225 1225 5 30 1230 1255

1935 842 842 5 30 847 872

1936 606 606 5 30 611 636

1937 512 800 5 30 517 830
32

Commercial hunt Subsistence hunt Total removals

Year Low High Low High Low High

1938 100 5 30 5 130

1939 100 5 30 5 130

1940 100 5 30 5 130

1941 100 5 30 5 130

1942 100 5 30 5 130

1943 100 5 30 5 130

1944 100 5 30 5 130

1945 100 5 30 5 130

1946 100 5 30 5 130

1947 100 5 30 5 130

1948 100 5 30 5 130

1949 100 5 30 5 130

1950 100 5 30 5 130

1951 100 5 30 5 130

1952 100 5 30 5 130

1953 100 5 30 5 130

1954 100 5 30 5 130

1955 100 5 30 5 130

1956 100 5 30 5 130

1957 100 5 30 5 130

1958 100 5 30 5 130

1959 100 5 30 5 130

1960 0 5 30 5 30

1961 0 5 30 5 30

1962 0 5 30 5 30

1963 0 5 30 5 30

1964 0 5 30 5 30

1965 0 5 30 5 30
33

Commercial hunt Subsistence hunt Total removals

Year Low High Low High Low High

1966 0 5 30 5 30

1967 0 5 30 5 30

1968 0 5 30 5 30

1969 0 5 30 5 30

1970 0 5 30 5 30

1971 0 5 30 5 30

1972 0 5 30 5 30

1973 0 5 30 5 30

1974 0 5 30 5 30

1975 0 5 30 5 30

1976 0 5 30 5 30

1977 0 5 30 5 30

1978 0 5 30 5 30

1979 0 5 30 5 30

1980 0 5 30 5 30

1981 0 5 30 5 30

1982 0 5 30 5 30

1983 0 5 30 5 30

1984 0 5 30 5 30

1985 0 5 30 5 30

1986 0 23 5 30 28 53

1987 0 23 5 30 28 53

1988 0 23 5 30 28 53

1989 0 23 5 30 28 53

1990 0 23 5 30 28 53

1991 0 23 5 30 28 53

1992 0 23 5 30 28 53

1993 0 23 5 30 28 53
34

Commercial hunt Subsistence hunt Total removals

Year Low High Low High Low High

1994 0 23 5 30 28 53

1995 0 23 5 30 28 53

1996 0 23 5 30 28 53

1997 0 23 5 30 28 53

1998 0 23 5 30 28 53

1999 0 23 5 30 28 53

2000 10 10 5 30 15 40

2001 22 22 5 30 27 52

2002 10 10 5 30 15 40

2003 26 26 5 30 31 56

2004 25 25 5 30 30 55

2005 31 31 5 30 36 61

2006 20 20 5 30 25 50

2007 0 0 5 30 5 30

2008 25 25 5 30 30 55

2009 24 24 5 30 29 54

2010 30 30 5 30 35 60

2011 33 33 5 30 38 63

2012 44 44 5 30 49 74

2013 0 23 5 30 28 53

2014 0 23 5 30 28 53