The Status of Endangered Whales: An Overview

HOWARD W. BRAHAM

Introduction

The Marine Mammal ProtectionAct (MMPA) of 1972 is the principalU.S. statute for conserving and pro­tecting marine mammals. Under it,the National Marine Fisheries Service(NMFS) of the Department of Com­merce's National Oceanic and At­mospheric Administration is responsi­ble for research on and managementof all whales, dolphins, and porpoises(collectively called cetaceans) withinthe U.S. 200-mile Fishery Conserva­tion Zone.

Of the 45 species of cetaceansfound in U.S. waters, eight are con­sidered so depleted that the specialprotection of the Endangered SpeciesAct (ESA) of 1973 is needed beyondthe MMPA. These eight, among theworld's nine largest cetaceans, are col­lectively called the "great whales."Listed as "endangered" under theESA, they include the gray whale,Eschrichtius robustus (Lilljeborg,1861); blue whale, Balaenopteramusculus (Linnaeus, 1758); fin whale,B. physalus (Linnaeus, 1758); seiwhale, B. borealis Lesson, 1828;humpback whale, Megapteranovaeangliae (Borowski, 1781); rightwhale, Balaena glacialis (Muller,1776); bowhead whale, B. mysticetusLinnaeus, 1758; and sperm whale,Physeter macrocephalus (Linnaeus,1758)1 (Fig. 1). The ninth great whale,Bryde's whale, Balaenoptera edeni, isnot listed as either endangered orthreatened.

Endangered Species Act

On 10 November 1978, the U.S.Congress passed Public Law 95-632

1Listed as Physeter catodon in the 1973 versionof the ESA.

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(Section 4(c», amending the En­dangered Species Act of 1973. One ofthe changes required the Secretaries ofCommerce and Interior to review thestatus and degree of endangerment ofall species listed in the Act at leastonce each 5 years to determinewhether any listed species should be 1)removed from the list, 2) changedfrom "endangered" to "threatened,"or 3) changed from "threatened" to"endangered."

In November 1982, the NMFSbegan a status review of the 19 en­dangered and threatened speciesunder its jurisdiction, including theeight endangered great whales. Thepapers in this special section of theMarine Fisheries Review summarizethe status reviews of those eightspecies and provide the biologicalbasis for any final management deci­sions. Full NMFS status reviews willbe made available separately, and willinclude management conclusions andrecommendations for any changes inthe listing of any species under theESA.

These eight papers thus review cur-rent knowledge of distribution,migration, stock identity, life historyand ecology, exploitation (principallycommercial whaling), populationabundance, and management con­cerns of the endangered great whales.We do not present a comprehensivereview of the literature, but ratherprovide summaries of the most ac­curate and current data. No newanalyses were conducted of popula­tion trends. The coeditors sought to

Howard W. Braham is Director, NationalMarine Mammal Laboratory, Northwest andAlaska Fisheries Center, National MarineFisheries Service, NOAA, 7600 Sand Point WayN.E., Bin CI5700, Seattle, WA 98115.

assemble and publish these papers toachieve the widest dissemination ofthe information to the public and tothe scientific and academic com­munities.

This introductory paper gives abrief overview of the status reviewprocess, summarizes estimates ofabundance and general status ofstocks, and acknowledges the help ofmany individuals in conducting thereviews and preparing the succeedingeight papers.

Listing Factors

Under the Endangered Species Actof 1973, a species is considered "en­dangered" if it is in danger of extinc­tion throughout all or a significantportion of its range, as a result of anyone of the five factors specified inSection 4(a)(I) (Table 1). A species isconsidered ''threatened'' if it is likelyto become endangered in the fore­seeable future due to any of thosesame factors.

Historically, most of the greatwhales qualified as "endangered" as aresult of overexploitation during com­mercial whaling (listing factor number2). The results of that exploitation,reflected in the change from initial

Table 1.-Factors for listing a species as "threatened" or"endangered" under the Endangered Species Act of 1973(Section 4(aX1XA·E), 1982 amendment~ Only one listingfactor need apply to list a species in either category.

Factors

1. The present or threatened destruction, modification,or curtailment of its habitat or range.

2. Overutilization for commercial, recreational, scien·tific, or educational purposes.

3. Disease or predation.4. The inadequacy of existing regulatory mechanisms.5. Other natural or manmade factors affecting its c9n­

tinued existence.

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~,,, (,.. ! ( <.;..:.r....\Blue whale

Humpback whale

46(4),1984

Figure I. - The eight endangered great whales.

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Table 2.-lnitial (precommercial whaling) and current population size estimates of large whales currently listed as "endangered" under the ESA. Stock or regional group estimates arethose summarized in the following eight papers in this special section of the Ma,ine Fishe,ies Review 46(4):7·64 (n.e. =no published estimate).

Population sizes ApproximatePopulation sizes Approximate

Species, stocks, percent of Species, stocks, percent ofor reporting area(s) Initial Current initial or reporting area(s) Initial Current initial

Gray whale Humpback whaleEastern North Pacific 15,000·20,000 13,450·19,210 Recovered E. North Atlantic n.e. n.e. n.e.Western North Pacific n.e. n.e. 1 n.e. W. North Atlantic >4,400 5,257·6,289 Recovered?

Northern Indian Ocean n.e. n.e. n.e.Blue whale North Pacific 15,000 < 1,200 8%

North Atlantic 1,100-1,500 100 6-9% Southern Hemisphere 100,000 2,500-3,000 2·3%North Pacific 4,900 1,400-1,900 29-39%North indian Ocean n.e. n.e. n.e. Bowhead whaleAntarctic l 150,000-210,000 1,000-8,000 <1-5% E. Greenland·Subantarctic Indian Spitsbergen 25,000 n.e. 1 <1%?

Ocean J 10,000 5,000 50% Davis Strait 11,000 n.e." <5%?

Fin whale Hudson Bay 680 n.e." n.e.

North Norway Several thousand n.e.Western Arctic 18,000 3,617-4,125 20-23%n.e.Sea of Okhotsk n.e.5 n.e: 5-10%?West Norway/Faeroe lsI. > 2,700 n.e." 10%?

Spain, Portugal,Right whale'British Isles >5,000 n.e. n.e.

Denmark Strait n.e. 1,791·11,584 n.e. North Atlantic n.e. n.e." n.e.

W. North Atlantic n.e. 3,590-6,300 n.e. North Pacitic n.e. n.e." n.e.

North Pacific 42,000-45,000 14,620-18,630 32-44% Southern Hemisphere n.e. 3,000? n.e.

Antarctic 1 400,000 85,200 21%Sperm whale'

Set whale North Atlantic 166,000 99,500 60%North Atlantic n.e. 4,957 n.e. Eastern North Pacific 311,000 274,000 88%North Pacific 45,000 22,000-37,000 49-82% Western North Pacific 309,400 198,100 64%Southern Hemispherel > 63,100-64,400 >9,800·11,760 15-19% Southern Hemisphere 590,600 410,700 70%

lThought to be nearing extinction or extremely low.'Six stock units or areas of all oceans in the Southern Hemisphere. For population estimates and status see Masaki and Yamamura (1978), Gulland (1981), and Butterworth (In press).'Pygmy blue whales.'Perhaps in the low hundreds.'Pehaps 6,500·10,000.'Stocks are reported here by general area only. See Braham and Rice (1964) for stock boundaries.'Exploitable popUlation size, and includes males and females (from Tables 4·6 in Gosha et aI., 1984); all estimates of initial and current abundance are considered provisional. Noestimates are available for the number of immature animals.

(precommercial whaling) populationsize to current population size arepresented in Table 2 for each species.

Listing a species in the ESA isbased on the best available scientificdata. In the absence of specific data,such as population growth rate, abun­dance, or known affect on theseparameters, other potentially limitingfactors to recovery (e.g., habitatdestruction, disease, and predation),provided broad coverage for protec­tion under the Act.

A discussion of the criteria used forlisting certain species as endangered isnot the intent of this paper. Con­siderable thought has gone into thisfor noncetacean species (e.g., Spar­rowe and Wight, 1975; Landry et aI.,1979; Anonymous, 1983). However,understanding the general nature andcriteria of endangerment is importantwhen evaluating the listing factors forreclassification (as required by Section4(c)). This necessitates knowingwhether the species or population isdeclining or nearing extinction, andwhether the quantity and quality of itshabitat is declining as well (Anony-

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mous, 1983). These and other popula­tion attributes are central to determin­ing current status, vulnerability, andrecovery potential (Sparrowe andWight, 1975). For certain manage­ment goals, it may also be importantto consider regional uniqueness andsociological and ecological factors aswell (Landry et al., 1979).

Endangered Great Whales

Seven of the endangered cetaceansare baleen whales, which filter theirfood between fringed baleen plates ar­ranged in a row along each side of thepalate. The eighth is the sperm whale,largest of the odontocetes, or toothedwhales.

By any standards, the great whalesare enormous (Fig. I). The blue whaleis the largest animal known to havelived on earth, some reaching lengthsof 98 feet (about 30 m) or more.Reports of blue whales well in excessof 100 feet have not been adequatelydocumented in the literature and maybe exaggerated.

It is because of their great size andthe large volume of commercial grade

oil in the blubber, the valued baleenor whale bone (in some species), andtheir predictable seasonal occurrence,that these great whales fell victim tocommercial whalers. As a result, thepopulations of these species wereseverely reduced in most of theworld's oceans within the past 200years. Most stocks were reduced sofast as to be commercially un­profitable within a few decades offishing.

Although few reliable data exist onthe sizes of most stocks at the lowpoint of their fisheries, a comparisonof current population size estimates toavailable estimates just prior to com­mercial whaling is instructive,especially when considering whether aspecies or stock fits the criteria forlisting under the ESA. But in review­ing the abundance estimates andgeneral status of stocks, I caution thereader to remember that many stockestimates are fraught with samplingand statistical biases which may causeover- or underestimation of the truevalue. I therefore recommend readingthe following papers and the literature

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The late Jim Johnson uses a crossbow to affix a plastic streamer-tag to a graywhale in Laguna Ojo de Liebre in Baja California. Photo by C. Goebel.

for a more in-depth appreciatIon ofthe estimates currently in use.

Status of Stocks:Population Abundance

Frequent reference is made in thefollowing papers to certain terms,perhaps new to the reader, such as"stock" or "population." Generallyspeaking, populations are geograph­ically isolated breeding units, i.e., twopopulations of the same species, onein the North Atlantic Ocean and theother in the North Pacific Ocean. Astock is a geographic subdivision of alarger population, and is usuallythought of as having some special at­tribute which sets it apart from othersof its kind or is also geographicallyseparated, but not necessarilyisolated. For example, a local group,or "stock," may be harvested at onetime of the year, such as on its sum­mer feeding ground, but on the winterbreeding grounds animals in thisgroup may intermingle with others ofthe same species. Humpback whalesin the North Atlantic, for example,summer in a number of separate"stock" areas, but most wintertogether in the West Indies. Anotherdefinition of stock also includes theattributes of isolation, in whichregional groups are apparentlyisolated from one another year­round, but may reside nearby. An ex­ample of this is the geographic separa­tion of the Sea of Okhotsk andwestern Arctic bowhead whales.Among the eight endangered greatwhales, there are many stocks (Table2 does not list all the stocks separate­ly). No species is so isolated as to berepresented by only one stock orpopulation and there are the usualdisagreements among scientists aboutcertain stock designations or bound­aries.

The Endangered Species Actspecifically concerns itself with thecontinued existence of species. How­ever, it has become convenient, andcertainly practical, to evaluate thestatus of populations or stocks ofwhales, rather than just the species.This is because more information isoften available for isolated groups

46(4),1984

than for either entire populations orthe species itself. This imbalance ofknowledge has, by necessity, led usinto a stratified decision-making pro­cess wherein possibly no conclusioncould be reached on a species (e.g., ifdeciding whether to reclassify) but asubdivision of the species, i.e., apopulation or stock, might be reclassi­fied. The net effect could then be tohave an "endangered" species withone or more stocks recovered.

On the basis of population abun­dance, as one criterion, a species (orstock) might be considered depleted ifits population size is below the lowerbound of the optimum sustainablepopulation size (operationally con­sidered by some to be the maximumsustainable yield level), currently de­fined (e.g., Tillman and Chapman,1981) as that level yielding maximumnet productivity which occurs at orabove 60 percent of initial populationsize. Although reliable quantitativedata are not available for all species, alarge number of stocks or species canbe considered "endangered" if onechooses to use this criterion (Table2).2

Based on population size alone,most stocks of large whales clearly fallwithin the definition of "endangered,"as defined in the ESA on the basis ofthe listing factors in Table I. Thegreat whales were listed as endangered

'''Depleled'' was likely the concept applied to theterm "endangered" in 1973. I use the concept of"degree of endangerment" as percent depleted,or current vs. initial stock size.

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as a result of commercial exploitation,as discussed in this volume on aspecies-by-species basis, or usingother criteria in the original documen­tation published in 1973 (Sec. 15U.S.c. 1531). These listings weremade despite a relatively sparse database. The purpose of this paper,however, is not to evaluate andrecommend whether each species re­main classified as endangered, norwhether certain stocks should bereclassified, although some implica­tions of this are presented in thefollowing discussion.

DiscussionFrom data presented in the follow­

ing eight papers, and summarized inTable 2, an estimate of the approx­imate percent of current to initialpopulation size for some great whalestocks is made. In Table 3 an evalua­tion is made of the possible level ofrecovery for each stock or species'group.

Only the eastern North Pacific graywhale and perhaps the western NorthAtlantic humpback whale may haverecovered to a population level similarto what it was prior to commercialwhaling. On the basis of populationsize alone, these two stocks plus mostsperm whale stocks seem likely can­didates for reclassification.

However, population size is not theonly criteria to be considered indeciding whether a stock warrantscontinued protection under the ESA.And, some doubts eJdst about the ac­curacy or completeness of data used

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to estimate initial stock sizes, especial­ly for humpback and sperm whales(Table 2). In the case of the graywhale, serious consideration must begiven to coastal habitat protection ashuman activities increase. In addition,about 170-190 gray whales from thisstock are killed each year by theSoviet Union, and usually less than 5are killed annually by AlaskaEskimos.

Western North Atlantic humpbackwhales, as well, are subject to a smallannual subsistence harvest in westGreenland and Bequia (Lesser An­tilles), and several are entangled eachyear in fishing gear along the eastcoast of the United States andCanada. Sperm whales appear to beabundant relative to their presumedinitial population sizes (when com-

Table 3.-A generalized evaluation 01 the possi·ble recovery of endangered whales by stock(s) orregional groupings.

Status

Perhaps recovered I

Eastern North Pacific gray whaleWestern North Atlantic humpback whale

Status uncertain2

North Pacific sei whaleNorth Atlantic sperm whale(s)North Pacific sperm whale(s)Southern Hemisphere sperm whale

Depleted'All stocks of blue whalesDavis Strait bowhead whalesea of Okhotsk bowhead whaleWestern Arctic bowhead whaleNorth Pacific humpback whale(s)Southern Hemisphere humpback whale(s)Antarctic fin whaleNorth Pacific fin whaleWestern North Atlantic fin whaleWestern Norway/Faeroe Isiands fin whaleSouthern Hemisphere right whale(s)Southern Hemisphere sei whale(s)

Nearing extinctionEast Greenland-Spitsbergen bowhead whaleWestern North Pacific gray whaleNorth Pacific right whale(s)

Insufficient data for judgementHudson Bay bowhead whaleDenmark Strait fin whaleNorth Norway fin whaleSpain·Portugal·British Isles fin whaleEastern North Atlantic humpback whaleNorthern Indian Ocean humpback whaleNorth Atlantic sei whaleNorth Atlantic right whale

I To estimated population size prior to commer­cial whaling.'Possibly above or near 60 percent of estimatedinitial population size.'Well below initial population size estimates, butmay include low populations which have shownsome increase (e.g., Southern Hemisphere rightwhales and western Arctic bowhead whale).

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pared with most stocks of baleenwhales reported in Tables 2 and 3).

Three stocks of great whales maybe nearing extinction: Western NorthPacific gray whale, east Greenland­Spitsbergen bowhead whale, andNorth Pacific right whale. Several re­cent unpublished sightings of graywhales in the western North Pacificand Sea of Okhotsk, of II bowheadsoff Frans Josef Land in the easternNorth Atlantic (Braham, 1984), and 2right whales in the southeastern Ber­ing Sea (Braham and Rice, 1984) sug­gest that at least a few individuals re­main. Unfortunately, there is littledirect evidence to indicate that thesestocks are either further declining orrecovering. The simplest explanationfor the increased sightings is increasedresearch.

Further consideration of the statusof stocks of all large whales awaitsrenewed dedication to research onsightings and, perhaps, stranding in­formation.

Acknowledgments

Many individuals gave of their timeto provide valuable comments, ad­vice, and assistance during prepara­tion of the papers in this special sec­tion of the Marine Fisheries Reviewon endangered whales. The authorsand I wish to extend our sincere ap­preciation to the following scientistslocated around the world who servedas reviewers: An Overview, CharlesKarnella (United States); gray whale,Robert Brownell, Jr., Stephen Reilly,and Steven Swartz (all United States);blue whale, Alfred Berzin (SovietUnion) and Sidney Brown (England);fin whale, Christina Lockyer(England), Edward Mitchell(Canada), and Carl R~rvik (Norway);sei whale, Ray Gambell (England);humpback whale, Kenneth BalcombIII and Deborah Glockner-Ferrari(both United States) and HalWhitehead (Canada); right whale,David Gaskin (Canada); bowheadwhale, Mark Fraker (United States)and Randall Reeves and Giles Ross(Canada); sperm whale, GeoffreyKirkwood (Australia) and EdwardMitchell (Canada).

We are also grateful to several pres­ent and past employees of the Na-

tional Marine Mammal Laboratoryand the Northwest and AlaskaFisheries Center who either reviewedthe papers or helped with preparingthe material for them: SandiBohenstiel, Marilyn Dahlheim,Charles Fowler, Sharon Giese, CarolHastings, Leola Hietala, Linda Jones,Bruce Krogman, Betty Lander,Willman Marquette, R. V. Miller,Mary Nerini, Jessie Page, JamesPeacock, Roger Pearson, DavidRugh, Laura Rutledge, MikeSeamans, Ronald Sonntag, MichaelTillman, Joanne Wejak, PamelaWilder, David Withrow, AllanWolman, and Muriel Wood. DaleRice was especially helpful withreviewing the papers he did notcoauthor. A special vote of con­fidence and appreciation is extendedto Charles Karnella and PatriciaMontanio of the NMFS headquartersoffice in Washington, D.C., who hadthe uneviable job of putting togetherthe entire ESA review for the NMFS.

This special section on endangeredwhales is respectfully dedicated to thememory of James H. Johnson whopassed away on 9 December 1983.

Literature CitedAnonymous. 1983. Final listing and recovery

priority guidelines approved. u.s. Fish Wild\.Serv., Endangered Species Tech. Bull.8(10):6-7.

Braham, H. W. 1984. The bowhead whale.Mar. Fish. Rev. 46(4):45-53.

_--,--.,--' and D. W. Rice. 1984. The rightwhale, Balaena glacialis. Mar. Fish. Rev.46(4):38-44.

Butterworth, D. In press. An estimate ofAntarctic blue whale population fromsightings data from the IWC/IDCR cruises.Rep. Int. Whaling Comm.

Gosho, M. E., D. W. Rice, and J. M. Breiwick.1984. The sperm whale, Physetermacrocephalus. Mar. Fish. Rev. 46(4):54-64.

Gulland, J. 198 I. A note on the abundance ofAntarctic blue whales. In Mammals in theseas, volume 3, general papers and large ceta­ceans, p. 219-228. Food Agric. Organ. U. N.,FAO Fish. Ser. 5, Vo\. 3.

Landry, J. L., L. P. Hirsch, and E. R.McCaffrey. 1979. A rating system for threat­ened and endangered species of wildlife. N.Y.Fish Game J. 26(1):11-21.

Masaki, Y., and K. Yamamura. 1978. Japanesepelagic whaling and whale sightings in the1976/77 Antarctic season. Rep. Int. WhalingComm. 28:251-261.

Sparrowe, R. D., and H. M. Wight. 1975. Set­ting priorities for the Endangered SpeciesProgram. Trans. N. Am. Wild\. Nat. Resour.Conf. 40:142-156.

Tillman, M. E., and D. Chapman. 1981. Fur­ther considerations of reasons for a moreconservative approach to whale management.Rep. Int. Whaling Comm. 31:601-604.

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