61(1), 1999 7

The Right Whales

Introduction

The right whales, Eubalaena spp., areidentified by their robust body, blackcoloration, lack of a dorsal fin, callosi-ties on the head region, and large,strongly bowed lower jaw (Fig. 2).While nomenclature for this speciesvaries, (some authors use the genusBalaena spp. (Braham and Rice, 1984;Rice12), they are referred to under thegenus Eubalaena spp. by the IWC(Hershkovitz, 1966; Schevill, 1986).The Northern and Southern Hemispherespecies have been taxonomically sepa-rated based on skeletal data (Müller,1954; Schaeff et al., 1991; Rice12). Agenetic study of the right whale mito-chondrial DNA control region suggests

that this current taxonomical separationis not valid, but through phylogeneticanalysis of mitochondrial lineages thereis evidence of independent taxonomicstatus for right whales in the North Pa-cific, North Atlantic, and SouthernOceans (Rosenbaum et al.13). In this re-view, Northern Hemisphere right whaleswill be referred to as Eubalaena glacialisglacialis Muller 1776, and the SouthernHemisphere right whales will be referredto as E. g. australis Desmoulins 1822 af-ter Rice12 and IWC designations.

12 Citation updated in proof: see Rice, 1998 inliterature cited.

13 Rosenbaum, H., R. L. Brownell Jr., M. Brown,C. Schaeff, V. Portway, B. White, S. Malik, L.Pastene, P. B. Best, P. J. Clapham, P. Hamilton,M. Moore, R. Payne, V. Rowntree, C. Tynan, andR. Desalle. 1998. A genetic review of inter-rela-tionships between right whales in different oceanareas. Unpubl. doc. SC/M989/RW23 submittedto the IWC Workshop on the Comprehensive As-sessment of Right Whales, Cape Town, SouthAfrica, May 1998.

Northern right whales are now themost endangered of the large whales.Recent data indicate that there is a smallbut unknown number of individuals inthe eastern North Pacific, and that thereare approximately 300 individuals in thewestern North Atlantic (Carretta et al.,1994; Goddard and Rugh, 1998; Knowl-ton et al., 1994). Southern right whales,in contrast, have shown signs of recov-ery over the past 20 years (Bannister,1990; Best, 1990; Payne, 1990). Thescarcity of right whales is the result ofan 800-year history of whaling that con-tinued into the 1960’s (Klumov, 1962)or as late as 1980 (Zemsky et al., 1995).

Northern right whales have been pro-tected for more than 60 years from com-mercial whaling, yet their numbers re-main low. In the North Pacific, the widedistribution of such low numbers ofanimals may have diminished mating

8 Marine Fisheries Review

Figure 2.—A right whale skimming the water’s surface for its zooplankton prey. Notice the whitish callosities and dark coloredbaleen. (W. A. Watkins, NMML Collection)

opportunities; therefore, chances of recov-ery for this stock appear bleak (Brahamand Rice, 1984). At least in the NorthAtlantic, human interactions (e.g. ves-sel strikes and fisheries entanglements)on their coastal calving grounds andelsewhere are thought to be one of thepredominate factors keeping abundancelevels low.

Distribution and Migration

Right whales have occurred histori-cally in all the world’s oceans from tem-perate to subarctic latitudes (Fig. 3).Right whales prefer shallow coastalwaters, but their distribution is alsostrongly correlated to the distribution oftheir zooplankton prey. In both hemi-spheres, they have been observed in lowlatitudes and nearshore waters duringwinter, where calving takes place, andthey tend to migrate to high latitudesduring the summer. In the North Atlan-tic and Southern Hemisphere, it appearsthat not all reproductively active fe-males return to the calving grounds eachyear (Kraus et al., 1986; Payne, 1986).

Right whale distribution in summer andfall in both hemispheres is likely linkedto the patchy distribution of their princi-pal zooplankton prey (Winn et al., 1986).

North Pacific

Historically, right whales rangedacross the entire North Pacific north oflat. 35°N (Braham and Rice, 1984).Sightings in the 20th century are fromas far south as the Yellow Sea and cen-tral Baja California to as far north asthe Okhotsk Sea and the Bering Sea(Fig. 4, 5) (Scarff, 1986). The IWC rec-ognizes North Pacific right whales asone contiguous stock, stating that at thistime there is not enough evidence ontheir specific distribution to designateotherwise (IWC, 1986a). During the1983 IWC Right Whale Workshop(IWC, 1986a), the Scientific Commit-tee recommended distinguishing twostocks, one in the east and one in thewest, but it stated “no conclusion canbe reached concerning the identity ofbiological populations.” At the 1998IWC Right Whale Comprehensive As-

sessment Workshop14 , it was tentativelydecided that there was insufficient dataabout where calving and breeding takeplace to confirm or deny the existenceof more than one stock in the NorthPacific. However, several preliminaryrecommendations regarding North Pa-cific stock structure were made duringthis 1998 workshop. First, the westernarea of the North Pacific should be des-ignated a management unit based oncurrent sighting information. Second,the current east and west separationshould stay in place until new data be-come available. And third, additional ge-netic analysis using historical samplesshould be undertaken (IWC14).

Lack of data on calving area locationsin the North Pacific and a number ofsightings of right whale concentrationsin the mid Pacific north of Hawaii, havechallenged the separation of eastern and

14 IWC. 1998. Draft report of the workshop on acomprehensive assessment of right whales: aworldwide comparison. Unpubl. doc. SC/50/Rep4submitted by the Scientific Committee to the IWC,Cape Town, South Africa, May 1998.

61(1), 1999 9

Figure 3.—Historic worldwide right whale distribution. Adapted from Braham and Rice (1984).

western stocks in the North Pacific(Scarff, 1986). Some researchers havesuggested the possibility of two west-ern North Pacific right whale stocksbecause of differences in migrationroutes and summer ranges: one travel-ing into the Okhotsk Sea and the otherto the east of the Kuril Islands andKamchatka Peninsula during summer(Klumov, 1962; Omura, 1986). Further-more, the relative scarcity of current andhistoric sighting records from the east-ern North Pacific (despite historic whal-ing in British Columbia) suggests that,if a separate eastern North Pacific rightwhale stock exists, it may be close toextinction (Braham and Rice, 1984;Scarff, 1986).

Historical whaling records providethe only information on possible migra-tion patterns for North Pacific rightwhales (Scarff, 1986). During summer,whales were found in the Okhotsk Sea,along the east coast of the KamchatkaPeninsula, the Kuril Islands, south ofthe Aleutian Islands, the Bering Sea(Bristol Bay), and the Gulf of Alaska(Fig. 4, 5). The fall and spring distribu-tion was the most widely dispersed,

with whales found in mid ocean watersand spanning from the Sea of Japan tothe eastern Bering Sea. In winter, thewhales were found in the Ryukyu Is-lands (south of Kyushu, Japan), theBonin (Ogasawari) Islands, the YellowSea, and the Sea of Japan (Fig. 5). Thecurrent distribution patterns and migra-tion routes of these whales are not known.

In the 20th century, individual rightwhale sightings have been scarce andgeographically scattered in the NorthPacific. For example, a lone right whalewas sighted off San Clemente Island,Calif. (Fig. 4) in 1992. This was onlythe twelfth reliable right whale sight-ing of this century in the eastern NorthPacific (Carretta et al., 1994). The ani-mal was photogrammetrically measuredto be 12.6 m (SD = 0.6 m), a relativelysmall animal, perhaps not yet sexuallymature (Carretta15). In July 1996, agroup of right whales was sighted inwestern Bristol Bay (Fig. 4) (Goddardand Rugh, 1998). The group consisted

of four individuals, one of which wasconsiderably smaller than the others.This was one of the first sightings of agroup of right whales in the northeastPacific this century, although sightings ofindividual animals have occurred morefrequently (Goddard and Rugh, 1998).

The Bristol Bay sighting was fol-lowed by another confirmed sighting inSeptember of a group of four individu-als 108 km southwest of the July sight-ing (Goddard and Rugh, 1998). Theseare only the fourth and fifth reliablesightings of right whales in the BeringSea since 1975.16 There are insufficientgood quality photographs to confirmresightings of particular individuals, butincreased search effort and reporting ofsightings to the appropriate investiga-tors is resulting in a better understand-ing of where these whales occur.

North Atlantic

The IWC recognizes two right whalestocks in the North Atlantic: western

15 Carretta, J. 1997. NMFS Southwest FisheriesScience Center, La Jolla, CA 92038. Personalcommun.

16 Platform of Opportunity Program 1975-1996.Unpubl. data on file at NMFS, NOAA, 7600 SandPoint Way N.E., Seattle, WA 98115.

10 Marine Fisheries Review

Figure 4.—Eastern North Pacific region.

and eastern (IWC, 1986a). The westernstock migrates along the North Ameri-can coast from Nova Scotia to Florida(Fig. 6). The eastern stock was histori-cally hunted by whalers along coastalIceland, off the British Isles, in the Bayof Biscay, and in Cintra Bay (Fig. 7).From whaling records, it appears thatthese whales migrated along the coastfrom northern Europe to northwest Af-rica. Today the distribution and migra-tion patterns of this eastern stock areunknown. There is also evidence fromwhaling records that a third stock mayhave existed in the central AtlanticOcean, migrating from east of Green-land to the Azores or Bermuda (Fig. 6,7) (Reeves and Mitchell, 1986).

In the western North Atlantic, fiveareas of “high use” were identified in thefinal recovery plan for the northern rightwhale (Fig. 8) (Anonymous, 1991a):

1) Coastal Florida and Georgia (Sebas-tian Inlet, Florida to mid-coast Georgia),

2) The Great South Channel (east ofCape Cod),

3) Massachusetts Bay and easternCape Cod Bay,

4) The Bay of Fundy, and5) Browns and Baccaro Banks (south

of Nova Scotia).

These areas were designated as north-ern right whale critical habitat17 due totheir importance to the reproductive andfeeding activities of the species (Kraus

and Kenney18). Generally, right whalesoccur off New England in spring and

17 Under Section 4 of the ESA, “critical habitat”must be designated “on the basis of the best sci-entific data available and after taking into con-sideration the economic impact.” Critical habi-tat is defined under Section 3 of the ESA as “spe-cific areas within the geographical area occupiedby the species....on which are found physical orbiological features (I) essential to the conserva-tion of the species and (II) which may requirespecial management considerations or protection.”Except under special circumstances, critical habi-tat shall not include the entire geographical areaoccupied by the species. (See also Fed. Regist. 50CFR pt. 226, Designated critical habitat.)18 Kraus, S. D., and R. D. Kenney. 1991. Infor-mation on right whales (Eubaleana glacialis) inthree proposed critical habitats in U.S. waters ofthe western North Atlantic Ocean. Final rep. toU.S. Mar. Mamm. Comm., Contr. T-75133740,T-75133753, 64 p., I-vi.

61(1), 1999 11

Figure 5.—Western North Pacific region.

early summer. Peak abundance occursin the Great South Channel along the100 m isobath and the paralleling ther-mal front in May (Kenney et al., 1995).In summer and fall, right whales occurfarther north into Canadian waters (i.e.the Bay of Fundy and Browns andBaccaro Banks) (Mitchell et al., 1986).Whales found on Browns and BaccaroBanks are predominately adult males,while those in the Bay of Fundy aremostly mother-calf pairs and juveniles.In fall and early winter, the whales movesouth. Known wintering areas for thisstock are along the southeastern U.S.coast, where calving takes place gener-ally from January through March(Brownell et al., 1986; Kraus et al.,

1986; Winn19). However, the winteringareas for an estimated 85% of the popu-lation are unknown (Kraus et al., 1986).Wintering areas may exist in the Gulfof St. Lawrence (Lien et al.20), New-foundland (Beamish, 1981; Lien etal.20), Greenland, Bermuda (Payne andMcVay, 1971), the Gulf of Mexico(Mead, 1986), and coastal waters ofNew York and New Jersey (Mead,

1986) (Fig. 6). Telemetry studies haverevealed movement patterns of consid-erable length and duration (Mate etal.21). Similar studies may identify ad-ditional areas where right whales occurduring winter.

Southern Hemisphere

The IWC recognized six stock areasin the Southern Hemisphere (Fig. 9)(Ohsumi and Kasamatsu, 1986; Dono-

19 Winn, H. E. 1984. Development of a rightwhale sighting network in the southeastern U.S.Final report for Mar. Mamm. Comm. Contr.MM2324805-6. NTIS PB84-240548, 12 p.20 Lien, J., W. Ledwell, and J. Huntington. 1989.Whale and shark entrapments in inshore fishinggear in Newfoundland and Labrador during 1989.Unpubl. rep. to the Newfoundland and LabradorDep. Fish.and Dep. Fish. Oceans, Can., 30 p.

21 Mate, B. R., S. Nieukirk, R. Mesecar, and T.Martin. 1992. Application of remote sensingmethods for tracking large cetaceans: North At-lantic right whales (Eubalaena glacialis). Finalrep. to U.S. Dep. Inter., Minerals Manage. Serv.,Alaska and Atl. OCS Reg. Off. Contr. 14-12-0001-30411, 167 p.

12 Marine Fisheries Review

Figure 6.—Western North Atlantic region.

van, 1991). Eight areas were provision-ally designated as management unitsduring a 1986 IWC Right Whale Work-shop, based loosely on Figure 9, catchhistories, and distributional data (IWC,1986a; Brownell et al., 1986). Theseeight units were used for mainly statis-tical purposes. During the 1998 Work-shop on the Comprehensive Assessmentof Right Whales, a critical evaluationwas conducted regarding designation ofright whale stock areas for managementand statistical purposes. Information con-sidered in this preliminary evaluation in-cluded catch histories, recent sightingdata, photographic identification, stable

isotope analysis, morphology, parasites,and genetic analysis (IWC14). This evalu-ation revealed a complex distribution.There were some preliminary designa-tions of stock separations, but overall nofinal stock designations for the SouthernHemisphere were made.

Ohsumi and Kasamatsu (1986) re-ported high concentrations of rightwhales between the subtropical andAntarctic Convergences (Fig. 10), withthe highest density of sightings southof western Australia. These Japanesesighting data indicated that the whaleswere found farthest south in January(the austral summer) and began mov-

ing north in February. This follows theseasonal residence patterns of whalesstudied in both South Africa and SouthAmerica, where animals begin arrivingon these wintering grounds from Maythrough June, peaking in abundanceduring September, and then leavingthese lower latitudes from Decemberthrough January (Payne, 1986; Best andScott, 1993).

Current and Historical Abundance

Most areas where right whales areknown to occur have only incompletecatch histories, which confounds anyestimates based on back-calculation and

61(1), 1999 13

Figure 7.—Eastern North Atlantic region.

catch per unit of effort (CPUE)22 (IWC,1986a). What is currently known aboutright whale abundance and accepted bythe scientific community has been sum-marized in Table 4.

North Pacific

The only population estimate fromthe North Pacific is for the Okhotsk Sea,

a northern right whale summering area.Data from surveys in 1989, 1990, and1992 have yet to be fully analyzed, buta preliminary analysis indicates thepopulation likely includes only a fewhundred animals (Brownell23). This es-timate has wide confidence intervalsand may be negatively biased (IWC14).

North Atlantic

In the western North Atlantic, thecurrent best estimate of 300 right whales

(Knowlton et al., 1994) is based on pho-tographic identification. Despite uncer-tainty surrounding this estimate (IWC14),it is clear that near failure of calf produc-tion from 1993 to 1995, increased calv-ing intervals, and the relatively large num-ber of human-induced mortalities, havecontributed to a growing concern over thefuture of the North Atlantic right whale.

Southern Hemisphere

A preliminary best estimate for totalSouthern Hemisphere right whale abun-dance is “about 7,000,” based on a tallyof estimates from separate breeding ar-eas (IWC14). During the 1998 Compre-

22 From IWC (1992a:238): “In practice, use of‘CPUE’ data was abandoned in each of the [IWC]management procedures during the later stagesof the [Revised Management Procedure] develop-ment process, in view of the great difficulty usu-ally experienced by the [Scientific] Committee inagreeing on the validity and interpretation of suchdata” [italics added].

23 Brownell, Robert L. 1998. NMFS SouthwestFisheries Science Center, La Jolla, CA 98038.Personal commun.

Canary Is.

14 Marine Fisheries Review

Figure 8.—Western North Atlantic right whale “high-use areas”: 1-coastal Florida and Georgia, 2-the Great South Channel,3-Massachusetts and eastern Cape Cod Bay, 4-Bay of Fundy, 5-Browns and Baccaro Banks (Anonymous, 1991a).

Figure 9.—IWC Southern Hemisphere stock “Area” designations for all endan-gered baleen whales (Donovan, 1991).

hensive Assessment Workshop, popu-lation models were constructed apply-

ing this preliminary current estimateand catch history data to a back-calcu-

lation simulation using various esti-mated rates of growth (IWC14).

Trends in Abundance

In the North Pacific, there are no dataon trends in abundance, but the paucityof sightings strongly suggests there hasbeen little or no growth in this popula-tion. As noted above, a number ofsightings have occurred in recent years,but this may be linked to increased sur-vey effort.

If the western North Atlantic rightwhale stock has grown since the periodof commercial exploitation, the increasehas been modest. The estimated annual

61(1), 1999 15

Figure 10.—Antarctic region; shaded area represents approximate location of Antarctic Convergence.

24 Kraus, S., P. K. Hamilton, R. D. Keeney, A.Knowlton, and C. K. Slay. 1998. Status and trendsin reproduction of the North Atlantic right whale.Unpubl. doc. SC/M98/RW1 submitted to theIWC Workshop on the Comprehensive Assess-ment of Right Whales, Cape Town, South Africa,May 1998.

population growth rate from 1986 to1992 was estimated at 2.5% (CV = 0.12)using photographic identification data(Knowlton et al., 1994). A significantincrease in the calving interval for1985–97 from 3.33 to 5.36 years(P<0.001) is further indication thatgrowth and recovery may indeed beslow (Kraus et al.24). Kenney et al.(1995) reported a long-term increase insighting rates within one feeding area

of the western North Atlantic (i.e.Great South Channel) of 3.8% per yearbetween 1979 and 1989, but extrapola-tion of this rate to the entire stock isinappropriate.

In contrast to northern right whalestocks, analysis of reproductive param-eters and net recruitment rates for south-ern right whale stocks reveals a slow,steady rate of recovery. Best (1990) re-ported an average annual increase of6.8% (95% CI = 4.6–9.0%) from 1971to 1987 in right whales occurring offSouth Africa. However, Butterworthand Best (1990) point out that this stockonly occupies 0.1 to 3.0% of its esti-mated initial (historical) carrying capac-

ity. Right whale abundance increased by11.7% (95% CI = 4.5–18.9%) to 13.0%(95% CI = 1.3–24.7%) per year from1977 to 1987 (Bannister, 1990) in wa-ters off western Australia. Payne (1990)reported an annual increase of 7.6% (SE1.7%) from 1971 to 1986 in the popu-lation occurring off Argentina. Theserates of increase must be viewed withcaution, however, because they are basedon only a portion of the population in anygiven year (i.e. not all mature femalesreturn to the calving grounds each year(IWC, 1986a; Best, 1993)), they are notbased on any explicit stock designations,and they do not take into account percapita reproductive successes (IWC14).

16 Marine Fisheries Review

Historic Exploitation Patterns

North Pacific

In the North Pacific, Japan huntedright whales from as early as the 1570’s(Omura, 1986) through 1964 (DuPasquier, 1986). By the end of the 19thcentury, North Pacific right whales wererare (Fig. 11). Most of this depletionwas due to pelagic whaling in the Seaof Japan (Omura, 1986), in the OkhotskSea (Kugler, 1986), and in the centraland eastern North Pacific (Kugler,1986) starting in the 1820’s. The num-ber of right whales reported taken after1909 are summarized in Table 6. Rightwhales have been legally protected inthe North Pacific and throughout theirentire range since 1935 (Brownell25).However, recent reports indicate that

Figure 11.—A North Pacific right whale awaiting flensing at an Alaska whaling station, circa 1930. University of WashingtonSpecial Collections, Lagen Collection, negative UW17495.

Table 6.—Reported takes of North Pacific right whales after 1910 (Anonymous, 1991a).

Years Takes North Pacific region Source

1910–30 123 Total (western and eastern) Scarff, 1986

1917–37 024 Alaska, British Columbia Brueggeman et al., 1986

1931–82 077 Western Scarff, 1986

25 Brownell, R. L. 1998. NMFS Southwest Fish-eries Science Center, La Jolla, CA 92038. Per-sonal commun.

Soviet whalers continued harvestingright whales until 1971 (Zemsky et al.,1995; Tormosov et al., 1998).

North Atlantic

Right whales were the first whalespecies to be exploited for commercialpurposes. Their large size, slow, andfairly predictable movements, coastaldistribution, and the fact that theyfloated when dead, made them theprime target of early European whalers(Cherfas, 1989). Basque whalers beganharvesting the first eastern North Atlan-tic right whales in the Bay of Biscay(Fig. 7), off the Spanish coast, around

the 1100’s (Aguilar, 1986). When rightwhales in the Bay of Biscay becamerare, the Basque whalers moved theiroperation to the Labrador and New-foundland coasts where they took anestimated 25,000 to 40,000 right whalesin an 80-year period (Aguilar, 1986). Bythe late 1600’s, western North Atlanticright whales were severely depleted,causing the era of Basque whaling tocome to a close (Barkham, 1984).

In the 1700’s, English and Dutchwhalers began commercial hunts forright whales off Spitsbergen, althoughby this time it appears that the whaleswere already scarce. In the late 1700’s,the French expanded their search forright whales to the South Atlantic, even-tually reaching Australia, New Zealand,and Chile (see below) (Cherfas, 1989).

Right whales were also hunted off theeastern United States from the 1600’sto the early 1900’s. The waters off east-ern Canada, Cape Cod, Nantucket,Long Island, New Jersey, DelawareBay, Georgia, and Florida all served aswhaling grounds during this period

61(1), 1999 17

(Fig. 6) (Schevill and Moore, 1983;Reeves and Mitchell, 1986). Since catchrecords from this region are based onthe quantity of commercial product soldrather than quantity of animals taken,no preexploitation trends or estimatesof the population can be ascertained(Reeves and Mitchell, 1986). All stocksin the North Atlantic were severely de-pleted by the late 1700’s (Kraus et al.,1988). However, between 1900 and1982, a total of 138 or 141 right whaleswere taken from the eastern North At-lantic (Brown, 1986). The most intenseepisode of whaling in this region oc-curred off the Shetlands, Hebrides, andIreland (Fig. 7) in the years 1906–10

(Brown, 1986). In addition, shore whal-ing along the U.S. east coast continueduntil 1924, with reported catches in thehundreds (Reeves and Mitchell, 1988).

Southern Hemisphere

When right whale numbers in theNorth Atlantic began to decline in thelate 1700’s, the French (and later theBritish) expanded their whaling opera-tions to the South Atlantic (du Pasquier,1986). From 1784 to 1794, under thecommand of mostly Nantucket whale-men, the coasts of Africa (e.g. Tiger’s Bay,Saldanha Bay, Saint-Helena Bay, TableBay), the Brazil Banks, and Falkland Is-lands were the focus of whaling for the

French (Fig. 12, 13). During this 10 yearperiod approximately 1,405 right whaleswere taken (du Pasquier, 1986). At thissame time, shore-based open-boat whal-ing began along the South African coastand lasted until 1912. These South Afri-can operations took approximately1,580 right whales (Best and Ross,1986). By the 1830’s, the right whale,which had been the principal target ofall South African whaling, was in no-ticeable decline (Best, 1970).

From 1817 through 1837, the Frenchincreased whaling efforts on the BrazilBanks east of South America where, by1837, they had taken an estimated 3,600right whales (du Pasquier, 1986). After

Figure 12.—Eastern South Atlantic/Western Indian Ocean region.

18 Marine Fisheries Review

Figure 13.—Western South Atlantic/Eastern South Pacific region.

1831, when the number of right whalesbeing caught declined in this area, whal-ing effort was expanded to Tristan daCunha (Fig. 12), the African coast, andeventually west into the Pacific viaCape Horn.

By 1837, the French were whaling offthe Chilean coast, where roughly 2,400right whales were taken by the Frenchuntil the year 1868 (du Pasquier, 1986).These catches included a high number ofmature females with some calves and ju-veniles, with potentially damaging con-sequences to the right whale’s reproduc-tive potential in these areas (Best andRoss, 1986; du Pasquier, 1986).

Whaling for right whales also oc-curred in the southern Pacific Ocean off

Australia and New Zealand (Bannister,1986a, b; Dawbin, 1986; du Pasquier,1986). Local bay whaling, or shore-based operations off the southern coastsof western Australia, first began in the1800’s for both right and humpbackwhales (Bannister, 1986a). Pelagicwhaling (conducted by the Australians,British, and French) began in these wa-ters during the mid to late 1830’s andlasted until the late 1880’s. After 1835,some French whaling vessels movedfrom the South Atlantic via the Cape ofGood Hope and began whaling (usingboth pelagic and bay operations), oper-ating mostly off New Zealand in thebays off Banks Peninsula, and in theSouth Indian Ocean, the bays of south-

ern Australia, Tasmania, and the ChathamIslands (Fig. 14) (du Pasquier, 1986).Dawbin (1986) estimated from whalinglogbooks and station records that at least26,000 right whales were caught insouthwest Pacific waters between 1827and 1899 by both bay and pelagic whal-ers. Dawbin (1986) also surmised thata major portion of world right whalecatches (one-third or more) from 1835to 1846 were taken off southeasternAustralia and New Zealand. This largecatch, however, was followed by a rapiddecline in the number of whales caught:300 whales after 1846, and less than 50whales after 1862 (Dawbin, 1986). Inwaters off southwestern Australia, asimilar pattern of rapid decline occurred

61(1), 1999 19

after a peak pelagic catch between 1838and 1849 (Bannister, 1986b). In theSouth Pacific, as in the South Atlantic,the high percentage of female and im-mature whales in the catches (particu-larly in the bay-type operations) mostlikely had long-term effects on the re-productive success of right whales inthese areas.

Current Exploitation

Currently, the IWC has assigned “Pro-tected Stock” status to all stocks of rightwhales (IWC, 1995b). The catch quotaon these whales is therefore set at zerofor all signatory nations of the IWC.

Recently revealed Soviet catchrecords show that at least 3,368 south-

Figure 14.—Eastern Indian Ocean/Western South Pacific region.

ern right whales were harvested be-tween 1951 and 1971 (Tormosov et al.,1998). These records are still incom-plete, and no information on the exactgeographic distribution of these catcheshas been reported although they areknown to have occurred in both theNorth Pacific and the Southern Hemi-sphere (Zemsky et al., 1995).

Life History and Ecology

Feeding

The feeding season for right whalesoccurs in the spring and fall in bothhemispheres, where they take advantageof large concentrations of zooplankton,primarily copepods, found in temper-

ate to subarctic waters. Oceanographicand bathymetric features, such as rela-tively cool water temperatures anddepths of 100–200 m adjacent to steeplysloping bottom topography, also seemto correspond to the utilization of cer-tain areas for feeding (Winn et al.,1986).

In the North Pacific, right whalesfeed primarily on copepods of the ge-nus Neocalanus, but they are alsoknown to prey on a variety of zooplank-ton species, namely Calanus marshallae,Euphausia pacifica, and Metridia spp.(Omura, 1986). In the North Atlantic,Calanus marshallae spp. are the pri-mary copepod prey (Kraus et al., 1988;Wishner et al., 1988; Murison and

20 Marine Fisheries Review

Gaskin, 1989; Mayo and Marx, 1990),with Centropages, Pseudocalanus(Mayo and Marx, 1990), juvenile eu-phausiids of the genus Thysanoëssa andMeganyctiphanes also found in the diet(Clapham, 1999). Southern right whalesalso feed upon calanoid copepods, as wellas on the pelagic post-larval stage ofMunida gregaria (Matthews, 1932), andkrill, Euphausia superba (Braham3).

Interspecific competition may limitthe prey available to northern rightwhales (Anonymous, 1991a; Kraus etal., 1988). In both the eastern NorthPacific and the North Atlantic, seiwhale, Balaenoptera borealis, distribu-tion is sympatric with northern rightwhale distribution. Because both spe-cies feed on small zooplankton species,there may be some competition (Mitchell,1975a). It is possible that some fish spe-cies also compete with right whales inthe Gulf of Maine, including sandlance,Ammodytes spp.; herring, Clupea spp.;Atlantic mackerel, Scomber scombrus;river herrings (shad, bluebacks, Alosaspp.); menhaden, Brevoortia tyrannus;and basking sharks, Cetorhinus maxi-mus. These fish share the northern rightwhale’s summer distribution and tosome extent utilize the same zooplank-ton prey species (Anonymous, 1991a).

Reproduction

Most right whale stocks utilize shal-low, coastal waters for nursery areas.Calving takes place between Decemberand April in the North Atlantic (Krauset al.26) and between late July and lateOctober in the Southern Hemisphere(Best, 1994a). Throughout their range,females give birth to their first calfaround 9 years of age (Hamilton et al.27;Cooke et al.28; Best et al.29). Calves areborn at 5.5–6.0 m in length (Best,1994a). The calving interval for rightwhales is between 2 and 7 years, withmeans ranging from 3.12 (95% CI 3.05–3.17) to 3.6 years (95% CI 28; Best et

al.29; Burnell30). In the North Atlantic,there was a significant increase (P<0.001)in the calving interval from 1985 to 1997from 3.33 to 5.36 years (Kraus et al.26).Gestation lasts from 357 to 396 days insouthern right whales (Best, 1994a), andweaning seems to be variable, reportedas 8–17 months in northern right whales(Hamilton and Marx, 1995).

Virtually nothing is known about re-productive parameters in North Pacificright whales. There have been no re-cently confirmed sightings of youngright whales in the North Pacific; onlythe report of a relatively small whale in1996 (Goddard and Rugh, 1998). In thewestern North Atlantic, a mean of 11.2(SE = 0.90) calves were born annuallybetween 1980 and 1992 (Waring et al.,1998). The 1986 Right Whale WorkingGroup (IWC, 1986a) provided a meangross annual reproductive rate (GARR)to aid in the calculation of populationgrowth rates (Brownell et al., 1986).This GARR represents the number ofyoung of the year as a proportion of theentire population. For the North Atlan-tic, the GARR has been estimated at 0.070to 0.092 calves per year (Brownell, 1986;Knowlton and Kraus31).

Natural Mortality

Little is known about natural mortal-ity in this species. North Atlantic rightwhales bearing scars from killer whale,Orcinus orca, attacks have been photo-graphed (Kraus, 1990), but the number

26 Kraus, S. D., R. D. Kenney, A. R. Knowlton, andJ. N. Ciano. 1993. Endangered right whales of thesouthwestern North Atlantic. Rep. to MineralsManage. Serv., 1110 Herndon Pkwy., Herndon, VA22070. Contr. 14-35-0001-30486.27 Hamilton, P. K., A. R. Knowlton, M. K. Marx,and S. D. Kraus. 1998. Age structure and longevity inNorth Atlantic right whales (Eubalaena glacialis).Rep. submitted to Mar. Ecol. Prog. Ser.

28 Cooke, J. G., R. Payne, and V. Rowntree. 1998.Updated estimates of demographic parametersfor the southern right whales (Eubalaena aus-tralis) observed off Peninsula Valdes, Argentina.Unpubl. doc. SC/M98/RW12 submitted to theIWC Workshop on the Comprehensive Assess-ment of Right Whales, Cape Town, South Africa,May 1998.29 Best, P. B., A. Branadao, and D. Butterworth.1998. Demographic parameters of southern rightwhales off South Africa. Unpubl. doc. SC/M98/RW16 submitted to the IWC Workshop on theComprehensive Assessment of Right Whales,Cape Town, South Africa, May 1998.30 Burnell, S. R. 1998. Aspects of the reproduc-tive biology and behavioral ecology of rightwhales off Australia. Unpubl. doc. SC/M98/RW19 submitted to the IWC Workshop on theComprehensive Assessment of Right Whales,Cape Town, South Africa, May 1998.31 Knowlton, A. R., and S. Kraus. 1989. Calvingintervals, rates and success in North Atlantic rightwhales (Abstr.) In Proceedings of the eighth bi-ennial conference on the biology of marine mam-mals. Soc. Mar. Mammal., Lawrence, Kan.

of whales killed by this predator is un-known. Using photo-identification datafrom the western North Atlantic stock,Kraus (1990) calculated an average natu-ral mortality rate of 17% per year in first-year right whales, while second- throughfourth-year whales had an average natu-ral mortality rate of 3% per year.

An “unusual mortality” event oc-curred in the western North Atlanticfrom January through March 1996,when there were eight reported rightwhale mortalities off the southeasternUnited States. Of these, only four wereexamined for cause of death, with threeshowing signs of human interaction(e.g. vessel collision and fisheries en-tanglement). Waring et al. (1998) cau-tioned against making any assumptionsabout this event being related to in-creased mortality in the population as awhole. However, there were at leastthree calf mortalities in 1996 which mayindicate fairly high neonatal mortality(Wang32)

Human-related Mortality

As noted above, the primary factorinfluencing the recovery of the rightwhale involves their occurrence incoastal habitats. This aspect of their dis-tribution places them in direct contactwith shipping traffic, fishery operations,coastal oil and gas development, andother human activities. The five factorsinfluencing the recovery of North Pacificand western North Atlantic right whalestocks are summarized in Table 7.

Fisheries Interactions

The magnitude and nature of fisher-ies interactions on right whales is notcompletely known. Apparently, somewhales survive an entanglement, but insome cases, injuries not initially lethalmay result in gradual weakening of en-tangled individuals, making them morevulnerable to some other direct causesof mortality (Kenney and Kraus, 1993).

Data are scant for North Pacific rightwhales: two fishery-related mortalitieshave been reported from Russian waters(Anonymous, 1991a; Kornev, 1994).

32 Wang, K. 1998. Fishery biologist, NMFSSoutheast Region, Protected Resources Division,9721 Executive Center Drive N., St. Petersburg,FL 33702.

61(1), 1999 21

Table 7.—Factors possibly influencing the recovery of right whale stocks under the ESA (1973) § 4 (a)(1),1992 Amend. (eastern North Atlantic data is not available).

Southern Hemisphere

Offshore oil and gas development; pollution;channel dredging

Whale watching vessel traffic

Unknown

Unknown

Vessel collisions

Western North Atlantic

Offshore oil and gas development; pollution; channel dredging

Whale watching and scientific research vessel traffic

Unknown

Current vessel traffic and fisheries regulations

Vessel collisions; entanglement in fishing gear (e.g. gillnets,lobster pots, seines, weirs)

North Pacific

Offshore oil and gas development(e.g. noise disturbance, oil spills)

Unknown

Unknown

Unknown

Entanglement in fishing gear(e.g. drift gillnets)

Factor

1. Present or threatened destruc-tion or modification of habitat

2. Overutilization for commercial,recreational,scientific, or edu-cational purposes

3. Disease or predation

4. Inadequacy of existing regula-tory mechanisms

5. Other natural or man-madefactors

In the western North Atlantic, an es-timated 57% of right whales bear scarsand injuries indicative of fishing gearentanglement (Kraus, 1990). Gillnets,lobster pots, seines, and fish weirs arethe primary gear types that entangleright whales (Anonymous, 1991a;Anonymous33). Entanglement in fixedgear was estimated to account for 7%of the known mortality in right whalesin the western North Atlantic from 1970through early 1993 (Kenney and Kraus,1993). Fisheries monitored by theNMFS from 1991 through 1995 had amean annual mortality rate of 0.4 (CV= 0.33) right whales (Waring et al.,1998). However, a review of sightingdata outside the observed fisheries(from records maintained by the NewEngland Aquarium and the NMFSNortheast Regional Office) for the years1991 through parts of 1996, indicatedan estimated annual mortality rate (dueto fisheries interactions) of 1.1 rightwhales (Waring et al., 1998). Theserates are in contrast to the IWC conclu-sion in 1996 that approximately oneright whale dies per year worldwide asa result of fishing gear entanglement.In response to this high level of mortal-ity (relative to the current populationlevel), Take Reduction Teams have beenestablished. These teams develop takereduction plans which include measuresto reduce incidental take of marinemammals in North Atlantic fisheries tobelow the current calculated removallevel (Anonymous, 1997). In the 1996

plan, the Atlantic Offshore CetaceanTake Team recommended prohibitingpair trawl, driftnet, and longline fisher-ies from operating in designated criti-cal right whale habitat (i.e. Cape CodBay, the Great South Channel, andsoutheast U.S. calving grounds) andduring periods of peak right whale oc-currence (Anonymous, 1997). In addi-tion, the Atlantic Large Whale TakeReduction Team recommended gearmodifications to gillnets and lobster potlines, as well as time-area fishing closuresin known right whale habitat (Anony-mous, 1997). As a result of stranding andentanglement records of large whalesfrom 1990 to 1994, the NMFS changedthe classification of the Gulf of Maine andU.S. Atlantic lobster pot fisheries fromCategory III to Category I.34

Vessel Collisions

The greatest known cause of mortal-ity among right whales in the NorthAtlantic is collision with ships. Out of27 documented mortalities in the NorthAtlantic from 1970 through 1991, 22%were caused by ship propellers sever-ing the tail stock, spine, or causingmortal wounds to the head region(Anonymous, 1991a). From 1991through the beginning of 1993, an ad-

ditional three mortalities were reportedin the North Atlantic as a result of col-lisions with vessels (Kenney and Kraus,1993). From 1991 to 1996, the reportedaverage mortality and serious injury ratedue to vessel collisions was three peryear (Waring et al., 1998). The low in-cidence (7%) of photographically iden-tified whales showing scars and woundsfrom ship propellers compared to thehigh rate of ship propeller wounds instranded animals indicates that mostinteractions between ship and whale arefatal to the whale (Kraus, 1990). In-creased monitoring and warning of ves-sels operating in the presence of rightwhales, particularly in areas of high calfdensity, such as in southeastern U.S.coastal waters, may be important com-ponents in efforts to reduce this formof mortality (Anonymous, 1997). Suchmonitoring has begun in the westernNorth Atlantic, where a real-time aerialwarning system, educational pamphlets,and delineation of critical right whalehabitat on nautical charts are all part ofthe effort to reduce ship strikes (Slay etal.35). Vessel-related mortality rates forstocks in the North Pacific are unknown.

In the Southern Hemisphere, threefatal ship strikes were reported fromBrazil from 1989 to 1993, and 10 fatalship strikes were reported from SouthAfrica from 1983 to 1997 at the IWCComprehensive Assessment Work-shop14. The Workshop concluded that

33 Anonymous. 1992. Proposed regime to gov-ern interactions between marine mammals andcommercial fishing operations: draft legislativeenvironmental impact statement. U.S. Dep.Commer., NOAA, Natl. Mar. Fish. Serv., Off.Protected Resour., Silver Spring, MD 20910.

34 A Category III fishery classification is assignedto those fisheries in which it is highly unlikelythat marine mammals will be incidentally takenduring a 20-day period, while a Category I fish-ery classification is assigned to a fishery that hasdocumented frequent incidental take and in whichit is highly likely that more than one marine mam-mal will be incidentally taken by a randomly se-lected vessel of the fishery during a 20-day pe-riod. See also Federal Register (1997), Takingof marine mammals incidental to commercialfishing operations; Atlantic Large Whale TakeReduction Plan regulations. Fed. Regist. 62(140),50 CFR pt. 229.

35 Slay, C. K., S. D. Kraus, P. K. Hamilton, A. R.Knowlton, and L. A. Conger. 1998. Early warn-ing system 1994-1997. Aerial surveys to reduceship/whale collisions in the North Atlantic rightwhale calving ground. Unpubl. doc. SC/M98/RW6 submitted to the IWC Workshop on theComprehensive Assessment of Right Whales,Cape Town, South Africa, May 1998.

22 Marine Fisheries Review

many of the problems faced by rightwhales in the North Atlantic with regardto ship traffic may also be faced by rightwhales in the Southern Hemisphere.Therefore, recommendations were maderegarding the control of shipping activityin areas where the density of right whalesis known or critical right whale habitathas been designated (IWC14).

Habitat Destruction

A continued threat to the coastal habi-tat of the right whale in both the NorthAtlantic and North Pacific is the under-sea exploration and development oftechniques for mining mineral depos-its, as well as the dredging of majorshipping channels. Offshore oil and gasactivities have been proposed off theU.S. middle and south Atlantic coastsand are currently being conducted in theBering Sea and in eastern North Pacificwaters (Anonymous, 1991a). Rightwhales also frequent coastal waterswhere dredging and its associated dis-posal operations occur on a regular ba-sis, such as along the southeastern U.S.coast. It is unknown to what extent theseactivities affect right whales. It appearsthat their level of sensitivity to noisedisturbance and vessel activity is relatedto the behavior and activity in whichthey are engaged at the time (Watkins,1986; Anonymous, 1991a), but furtherstudy is necessary.

Pollution

Relatively low levels of organochlo-rine contaminants have been found inright whale blubber, most notably PCBand DDT (Woodley et al., 1991). Con-taminant levels are low because baleenwhales feed lower on the food web thanodontocetes and follow seasonal migra-tion patterns that decrease their expo-sure to localized contaminants. The lev-els at which these contaminants occurin baleen whales are likely too low tobe linked to any direct mortality or im-paired reproductive functioning, andtherefore they are not considered pri-mary factors in slowing the recovery ofany stocks of large whales (O’Shea andBrownell, 1994). However, some con-taminants affect phytoplankton andzooplankton density and distribution,and therefore the energetics and distri-

bution of right whales may be affected(Anonymous, 1991a).

Whale Watching andSmall-boat Regulations

Concern has been raised over the im-pacts of whale-watching activities andscientific field research on right whaleaggregations, particularly in the westernNorth Atlantic (i.e. Cape Cod Bay andlower Bay of Fundy) (Anonymous,1991a). These activities, like the indus-trial shipping activities discussed above,have the potential to disturb right whalesor disrupt their activities. The effect ofthese human activities on right whales isnot known. Nonetheless, to diminish thelikelihood of vessel disturbance and toreduce the risk of a vessel striking a whale,the NMFS issued regulations in 1997 thatprohibit the approach of any vessel, notin possession of a special NMFS permit,within 500 yards of a right whale in wa-ters off the U.S. east coast (Anonymous,1987; Federal Register36).

Classification Status

The northern right whale was listedas endangered under the ESA in 1973and designated depleted under theMMPA. This status applies to all stocksin U.S. waters (Anonymous, 1994b).Worldwide, all right whale stocks aredesignated as “Protected Stock” by theIWC. Under this designation, the IWCrecognizes that all stocks of right whalesare 10% or more below their MSY level(IWC, 1995b).

Threats to right whales continue toexist (Table 7); however, there is incom-plete information regarding potentialthreats in the eastern North Atlantic.Any reevaluation of northern and south-ern right whale status awaits collectionof more reliable information on abun-dance, distribution, and threats fromhuman activities in the North Pacific,eastern North Atlantic, and SouthernHemisphere, as well as the developmentof objective delisting criteria.

The eastern North Pacific right whalestock clearly remains severely depleted.Virtually nothing is known about its cur-

rent size, trends in abundance, distribu-tion, or migration patterns. The size of thisstock is thought to be very small, but thereare no reliable estimates of abundance.The classification of this stock should notchange at this time and is not likely tochange in the foreseeable future. Prelimi-nary survey data from 1989, 1990, and1992 in the western North Pacific yieldsa preliminary estimate of only a few hun-dred animals (Brownell23).

As noted above, the size of the west-ern North Atlantic stock is estimated atabout 300 individuals. This number hasnot increased significantly since thespecies received international protec-tion in 1935. It is generally agreed thatthe current rate of population increase islow, about 2.0–2.5% annually (IWC14).In addition, the western North Atlanticpopulation has exhibited annual oscilla-tion in recruitment, a near-failure of calfproduction from 1993 to 1995, and asignificant increase in calving intervalsbetween 1985 and 1997 (IWC14). Also,mortality and serious injury from hu-man activities continue to slow recov-ery. In this regard, the potential biologi-cal removal (PBR) level37 for the NorthAtlantic right whale, estimated at 0.4whales per year (Waring et al., 1998),has been exceeded for each of the last 5years. From 1991 to September 1996the estimated average annual human-induced mortality and serious injuryrate (both from fishery and nonfisheryrelated activities) was three whales(Waring et al., 1998).

The northern right whale recoveryplan (Anonymous, 1991a) stated thatrecovery was likely to be slow and es-timated that even under the best condi-tions, it would likely take more than 100years for the species to recover topreexploitation levels in both the Pacificand Atlantic Oceans. Therefore, withregard to the western North Atlanticstock, the plan’s interim goal was tooutline a strategy for changing the sta-

36 Federal Register. 1996. Regulations govern-ing the taking and importing of marine mammals.Fed. Regist. 50 CFR pt. 216.

37 Under the 1994 MMPA reauthorization, PBRis defined as the product of minimum popula-tion size (Nmin), half the maximum productivityrate, and a specified “recovery” factor. For en-dangered species, the recovery factor is typically0.1. And for cetaceans, the default maximumnet productivity rate is 4%, if a current, statisti-cally reliable maximum productivity rate is notavailable.

61(1), 1999 23

tus of the population from endangeredto threatened. This strategy recom-mended that a classification changeshould only be considered after:

1) The size of the population recoveredto a level of 6,000 individuals,

2) The population increased steadilyover a period of 20 years or more atan average annual net recruitmentrate of at least 2% per year, and

3) An effective program was in place toreduce human-related mortality andensure that deterioration of essentialhabitat was not likely to occur, therebyallowing abundance to increase to theoptimum sustainable population level.

New data on population size andtrends in abundance have been collectedsince the 1991 recovery plan and shouldbe used in revising Criteria 1 and 2.

Criteria 3 should also be reevaluated,since programs are in place to facilitatethe recovery of this population, butthreats from human activities remain(Table 7). Given existing and continuingthreats to northern right whales and littleor no evidence of moving toward attain-ing population increase criteria, the en-dangered status of the western North At-lantic right whale stock should remainunchanged for the foreseeable future.