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The Great : History and Status of Six Listed as Endangered Under the U.S. Endangered Species Act of 1973

Item Type article

Authors Perry , Simona L.; DeMaster, Douglas P.; Silber , Gregory K.

Download date 24/09/2021 18:11:28

Link to Item http://hdl.handle.net/1834/26411 The Fin

Introduction predatory advantage over other balaen- 1994a). Most migrate seasonally from opterids (Tershy and Wiley, 1992). The relatively high-latitude Arctic and Ant- The , Balaenoptera physalus dorsal fin is generally falcate with a arctic feeding areas in the summer to Linnaeus 1758, is the second largest mem- pointed tip, but it may be quite variable relatively low-latitude breeding and ber of the family Balaenopteridae (after in its shape (Fig. 26). calving areas in winter. Arrival time on the , B. musculus). Mature The fin whale is usually found alone the summer feeding areas may differ range from 20 to 27 m in length, or in small groups, and the species ap- according to sexual class, with pregnant with mature females being approxi- pears to have no well-defined social females arriving earlier in the season mately 1.47 m longer than mature males structure. Like other balaenopterids, than other whales (Mackintosh, 1965). (Aguilar and Lockyer, 1987). All fin they have fringed baleen plates instead The location of winter breeding areas whales have a consistent pattern of of teeth, and ventral grooves which ex- is still uncertain. These whales tend to asymmetrical pigmentation which is pand during feeding and allow the migrate in the open ocean, and therefore particularly recognizable on the head whale to engulf large quantities of wa- migration routes and the location of win- region. The whale’s underside, right lip, ter along with small and fish tering areas are difficult to determine. and right baleen plate are yellow-white, prey items. while their main body, left lip, and left North Pacific Distribution and Migration baleen plate are a fairly uniform gray- The IWC’s Scientific Committee rec- blue color. This asymmetry may be Fin whales inhabit a wide range of ognized two management stocks in the linked to the whale’s feeding behavior, latitudes between lat. 20Ð75°N and 20Ð North Pacific: the East China (Fig. 5) but there is no evidence that their un- 75°S (Fig. 27) (Mackintosh, 1966; and the rest of the North Pacific (Donovan, usual coloration gives them any type of Leatherwood et al., 1982; Anonymous, 1991). One reason for this broad desig-

Figure 26.—Two fin whales, one noticeably smaller, surface simultaneously revealing their falcate dorsal fins and dark colora- tion. S. Hill, NMML Collection.

44 Marine Fisheries Review nation is the lack of data on geographic tral coast, although there is are scarce in summer and winter (Lee, or genetic separation within the species. a seasonal peak during the summer and 1993; Wade and Gerrodette, 1993). Because fin whales tend to inhabit such a autumn (Barlow, 1995; Forney et al., Three stocks have been designated in wide range of latitudes in all seasons, it is 1995; Dohl et al.78). Fin whales have U.S. waters of the North Pacific for hard to predict where individual animals also been found in summer off Oregon stock assessment and management pur- travel during pelagic migrations. (McDonald et al., 1995; Green et al.75) poses: 1) California/Oregon/Washing- Mizroch et al. (1984b) suggested five and in summer and autumn in Shelikof ton, 2) , and 3) (Barlow possible stocks within the North Pacific Strait (north of Kodiak Island, Alaska) et al., 1997; Hill et al., 1997). Around based on histological and tagging ex- and the Gulf of Alaska (Brueggeman et Hawaii, the fin whale is rarely sighted periments (Fig. 4, 5) (Fujino, 1960; al.79). The Gulf of California is inhab- (Shallenberger80; Balcomb81), but Rice, 1974; Tershy et al., 1993): ited year-round by fin whales, with a acoustic recordings off Oahu and Mid- peak in abundance during winter and way Islands suggested a migration into 1) East and West Pacific (intermingling spring (Tershy et al., 1993; Silber et al., Hawaiian (U.S. EEZ) waters in autumn around the Aleutian Islands), 1994). Whether fin whales found off and winter (Thompson and Friedl, 2) East China Sea, southern and central California during 1982). 3) British Columbia, summer migrate to the Gulf of Califor- 4) Southern/Central California to Gulf nia for winter awaits further investiga- North Atlantic of Alaska, and tion (Barlow et al., 1997). In low latitudes In 1976, the IWC identified seven 5) Gulf of California. of the eastern tropical Pacific, fin whales stock areas in the North Atlantic (Donovan, 1991) based on “statistical Discovery tags38 injected and some- 78 Dohl, T. P., R. C. Guess, M. L. Duman, and R. convenience” and history of exploita- C. Helm. 1983. Cetaceans of central and north- times recovered during the era of com- ern California, 1980-83: Status, abundance and tion (Fig. 28): mercial demonstrated possible distribution. Contr. 14-12-0001-29090. Final rep. to Minerals Manage. Serv., 284 p. southern California wintering areas and 80 79 Brueggeman, J., G. A. Green, K. C. Balcomb, C. Shallenberger, E. W. 1981. The status of Ha- summering areas ranging from central E. Bowlby, R. A. Grotefendt, K. T. Briggs, M. L. waiian cetaceans. Rep. MMC-77/23 prep. for Mar. California to the Gulf of Alaska (Rice, Bonnell, R. G. Ford, D. H. Varoujean, D. Heine- Mammal. Comm., Contr. MM7AC/28, 79 p. 1974). Other researchers have more re- mann, and D. G. Chapman. 1990. Oregon-Wash- 81 Balcomb, K. C. 1987. The whales of Hawaii, ington and seabird survey: Infor- including all species of marine mammals in Ha- cently found year-round concentrations mation synthesis and hypothesis formulation. Prep. waiian and adjacent waters. Marine Mammal of fin whales off the southern and cen- for U.S. Dep. Inter., OCS Study MMS 89-0030. Fund, , Calif., 99 p.

Figure 27.—Worldwide fin whale distribution. Adapted from Mizroch et al. (1984b).

61(1), 1999 45 A fin whale breaking the surface. Note the white coloration on the lower lip. S. Kraus, NMML Collection.

1) North , 2) West Norway-Faroe Islands, 3) British Isles- and , 4) East -, 5) West Greenland, 6) Newfoundland-Labrador, and 7) .

In 1991, during the Special Meeting on the Comprehensive Assessment of North Atlantic Fin Whales, the IWC’s Scientific Committee adopted alterna- tive stock boundaries, which relate to historic catch areas and may be useful for assessing population abundance (IWC, 1992b; Butterworth and Punt, 1992). However, these suggested boundaries were not considered repre- sentative of biological stocks by the Scientific Committee (IWC, 1992b). Underwater listening systems (part of the IUSS) have demonstrated that the fin whale is the most acoustically com- mon whale species heard in the North Atlantic (Clark, 1995). They are acous- Figure 28.—North Atlantic fin whale stock boundaries recognized by the IWC tically detected year-round in the Nor- (Donovan, 1991). wegian Sea, and vocalizations show a sea-

46 Marine Fisheries Review sonal shift in which whales move south- whales breed to validate this designa- CPUE22 (Braham3). Waring et al. (1998) ward during autumn and northward dur- tion (IWC, 1992b). considered 1,700 (CV = 0.59) fin ing spring in this region. The IUSS tracked whales to be the minimum population fin whales during seasonal migrations Current and Historical Abundance estimate (Nmin) for an area from the along both the western and eastern Atlan- northern to the lower Bay North Pacific tic. The autumn southward migration pat- of Fundy (Nova Scotia stock) based on tern in the western North Atlantic was The most current (1991) population line-transect surveys in July through from Newfoundland-Labrador, past Ber- estimate for the entire North Pacific is September 1991Ð92. For the British muda, and into the West Indies, while in between 14,620 and 18,630 based on Isles/Spain and Portugal stock, Braham3 the eastern North Atlantic, the pattern was history of catches and trends in CPUE22 provided in 1991 an initial, preex- from the British Isles to the coasts of Spain (Braham3). Prior to exploitation, there ploitation population estimate of 10,500 and Gibraltar (Fig. 6, 7) (Clark, 1995). were an estimated 42,000Ð45,000 fin (95% C.I. 9,600Ð11,400) fin whales. In U.S. waters of the North Atlantic, whales in the entire North Pacific the NMFS has recently designated one (Ohsumi and Wada, 1974). In the early Southern Hemisphere stock of fin whale (Waring et al., 1998). 1970’s, this entire North Pacific popu- In the Southern Oceans, the most The fin whale is common from Cape lation had been reduced to between current (1979) population estimate is Hatteras northward (Fig. 6), where the 13,620 and 18,630 fin whales (Ohsumi 85,200 (no CV) fin whales based on the species accounted for 46% of all large and Wada, 1974). history of catches and trends in CPUE22 whales and 24% of all cetaceans sighted The most recent data from 1991, 1993, (IWC, 1979). In addition, 15,178 over the continental shelf between Cape and 1996 line-transect surveys of waters whales (no CV given and uncorrected Hatteras and Nova Scotia during 1978Ð off California, , and Oregon for probability of sighting) were esti- 82 aerial surveys (Waring et al., 1998). yielded an estimated current population mated to occur within surveyed areas The single most important area for this abundance of 1,236 (CV = 0.20) fin south of lat. 30°S by combining data species appeared to be from the Great whales (Barlow74). In Alaska, a survey in from JSV and IWC/IDCR 1978Ð88 South Channel, along the 50 m isobath August 1994, covering 2,050 n.mi of ship-based surveys (IWC, 1996a). Prior past , over Stellwagen Bank, track-line south of the Aleutian Islands, to commercial exploitation these south- and past Cape Ann to Jeffreys Ledge reported only four fin whale groups in this ern stocks were estimated to contain (Hain et al., 1992). Fin whales in this area (Forney and Brownell68). No abun- 400,000 fin whales (IWC, 1979). region are the dominant cetacean spe- dance estimates could be calculated for Historic Exploitation Patterns cies and therefore most likely have the Alaska waters from these sparse data. largest impact on the ecosystem of any Also, there is no current abundance esti- As early as the mid-17th century, the cetacean (Hain et al., 1992). mate available for Hawaiian waters. Dur- Japanese were capturing fin, blue, and Photoidentification studies in west- ing the early 1970’s, an estimated 8,520Ð other large whales using a fairly primi- ern North Atlantic feeding areas, par- 10,970 fin whales occured in the eastern tive open-water netting technique (T¿nn- ticularly in Bay, have half of the North Pacific (Braham3). essen and Johnsen, 1982; Cherfas, 1989). shown a high rate of annual return by If the estimates from the 1970’s and In 1864, explosive harpoons and steam- fin whales, both within years (49%) and 1991 (Ohsumi and Wada, 1974; Braham3) powered catcher boats were introduced between years (45%) (Seipt et al., are accurate, no increase in fin whale in Norway, allowing the large-scale ex- 1990). This apparent site-fidelity may numbers has occurred in the past 20 ploitation of previously unobtainable be similar to matrilineally directed site- years despite an IWC ban on whaling whale species. The North Pacific and fidelity in humpback whales (Seipt et in the North Pacific. Antarctic whaling operations soon al., 1990; Clapham and Seipt, 1991; added this modern equipment to their North Atlantic Agler et al., 1993). Evidence regarding arsenal (T¿nnessen and Johnsen, 1982). where the majority of fin whales win- There is no current estimate for the After blue whales were depleted in most ter, calve, and mate is still scarce. Neo- entire North Atlantic, but each IWC areas, the smaller fin whale became the nate strandings between October and stock area, with the exception of North focus of operations. Worldwide, fin January along the U.S. mid Atlantic Norway, has a tentative estimate (Table whales were severely depleted by com- coast suggest the possibility of an off- 13). In the years before exploitation, mercial whaling activities; over 700,000 shore calving area (Hain et al., 1992). there were an estimated 30,000-50,000 were landed in the 20th century (Cherfas, whales in the entire North Atlantic, and 1989). Southern Hemisphere in the decade 1960Ð70, this population North Pacific The IWC has divided the Southern was estimated to number approximately Oceans into six stock ar- 31,320 whales (Sergeant, 1977). In the early Japanese nearshore net eas (Fig. 9) (Donovan, 1991). These The most current (1991) population fisheries, 480 fin whales were taken areas may loosely correspond to fin estimate for the western North Atlantic from the mid 1600’s to 1913 (Omura, whale stocks, but there is still insuffi- is between 3,590 and 6,300 fin whales 1986). Between 1914 and 1975, over cient distributional data on where these based on the catch history and trends in 26,040 fin whales were caught through-

61(1), 1999 47 Table 13.—Current abundance estimates of North Atlantic fin whale stocks (N.e. = no published estimate; no data for North Norway stock).

Abundance Coefficient of IWC stock designation estimate variation 95% C.I. Source1

Nova Scotia Stock (U.S. territory): Cape Hatteras, NC to Nova Scotia 14,680 (spring & summer) 0.230 N.e. CeTAP70 Cape Hatteras, NC to Nova Scotia 4,1194 (summer) 0.180 N.e. Anonymous7 Cape Hatteras, NC to Nova Scotia 41,529 (summer) 0.190 N.e. Anonymous7 Cape Hatteras, NC to Georges Bank 4,3135 (summer) 0.560 N.e. Waring et al., 1992 Northern Gulf of Maine and 12,700 (summer) 0.590 N.e. Waring et al., 1998

Newfoundland/Labrador Stock2 13,253 1.420 N.e. IWC, 1992c West Greenland Stock3 13,178 N.e. 26Ð382 Larsen, 1995 East Greenland/Iceland Stock 11,563 0.261 N.e. Gunnlaugsson and Sigurjónsson, 1990 British Isles/Spain and Portugal Stock4 17,355 0.266 10,400Ð28,900 Buckland et al., 1992 British Isles/Spain and Portugal Stock4 17,507 0.150 5,600Ð10,100 Goujon et al., 1995 British Isles/Spain and Portugal Stock 14,485 N.e. 3,369Ð5,600 Braham3

1 Source footnote numbers refer to text footnote numbers. 2 From 1965 to 1972 mark-recapture analyses. 3 Excludes areas of high density from previous surveys. 4 The 17,355 estimate covered 415,290 n.mi of trackline; the 7,507 estimate covered 204,929 n.mi of trackline.

out the North Pacific (Braham3). The pleted to the point of being economi- being caught per year. The IWC pro- Japanese fishery for fin whales peaked cally unsuitable for further exploitation. hibited the taking of fin whales from the in 1914 when 1,040 whales were cap- Still, fin whaling resumed in the 1950’s Southern Hemisphere in 1976. tured, and thereafter declined to be- off northwest Spain where, from 1954 Recently released Soviet whaling tween 300 and 400 whales per year un- to 1987, a few hundred fin whales were records indicate a discrepancy between til World War II. After World War II, caught each year (Aguilar and Lens, reported and actual fin whale catch the fin whale fishery was never as suc- 1981; Sanpera and Aguilar82). numbers by the U.S.S.R. in southern cessful due to the scarcity of animals, waters between 1947 and 1980 (Zemsky Southern Hemisphere and in 1975 the IWC banned fin whale et al., 1995). The U.S.S.R. previously in the western North Pacific. From 1904 to 1975, there were reported 52,931 whales caught, whereas Along the west coast of North Amer- 703,693 fin whales taken in Antarctic the new data indicates that only 41,984 ica, some fin whales were taken off Cali- whaling operations (IWC, 1990). Whal- were taken. One reason for this discrep- fornia, British Columbia, and Alaska (Fig. ing in the Southern Oceans originally ancy may lie in the mistaken identifica- 29), but this hunt ceased by 1972. In the targeted humpback whales, but by 1913 tion of sei whales as fin whales in the rest of the North Pacific and the Bering this target species became rare, and the original reporting. Sea, catches dropped after the mid 1960’s. catch of fin and blue whales began to Current Exploitation The IWC issued a ban on commercial increase (Mizroch et al., 1984b). From whaling for fin whales throughout the 1911 to 1924, there were 2,000Ð5,000 From 1988 to 1995, there have been North Pacific in 1976. fin whales taken per year. After the in- 239 reported kills of fin whales from troduction of factory whaling ships in the North Atlantic (Table 10). There is North Atlantic 1925, the number of whales taken per currently a “subsistence”34 take of fin Over 48,000 whales were taken year increased substantially. From 1931 whales from the West Greenland stock. throughout the North Atlantic between to 1972, approximately 511,574 fin The IWC set a catch limit of 19 whales 1860 and 1970 (Braham3). Fisheries whales were caught (Kawamura, 1994). for the years 1995, 1996, and 1997 in existed off Newfoundland, Nova Scotia, In 1937 alone, over 28,000 fin whales West Greenland. All other fin whale Norway, Iceland, the Faeroe Islands, were taken. From 1953 to 1961, the stocks had a zero catch limit for those Svalbard (Spitsbergen), the islands off number of fin whales taken per year same years (IWC, 1995b). However, the British coasts, Spain, and Portugal continued to average around 25,000. In Iceland (East Greenland/Iceland stock) (Fig. 6, 7, 18). These whales were rarely 1962, sei whale catches began to in- reported a catch of 136 fin whales in taken in U.S. waters, except when they crease as fin whales became scarce. By the 1988/89Ð1989/90 seasons, but has ventured near the shores of Province- 1974, less than 1,000 fin whales were since ceased reporting fin whale kills town, Mass., during the late 1800’s to the IWC. Butterworth and Punt (Clark, 1887; True, 1904). (1992) have suggested that a catch of The fin whale fishery off Spain and 82 Sanpera, C., and A. Aguilar. 1984. Historical 100 whales per year from this East review of catch statistics in Atlantic waters off Portugal began in 1921, but it took only the Iberian Peninsula, 23 p. Unpubl. doc. SC/36/ Greenland/Iceland stock would be a 7 years for the local stocks to be de- 014 submitted to Rep. Int. Whal. Comm. sustainable mortality level.

48 Marine Fisheries Review Figure 29.—Fin whale on flensing platform. Note the bicolored baleen plates. University of Washington Special Collections, Lagen Collection, negative UW1611.

Life History and Ecology Kawamura, 1982; CeTAP70). Thus, they Lockyer and Brown, 1979; Ratnaswamy may be less prey selective than blue, and Winn, 1993). Conception occurs dur- Feeding humpback, and right whales. However, ing a 5-month winter period in either Fin whales spend the summer feed- fin whales do depend to a large extent hemisphere. After a 12-month gestation ing in the relatively high latitudes of on the small euphausiids and other period, a single 6 m calf is born both hemispheres, particularly along the zooplankton species. In the Antarctic, (Mizroch et al., 1984b). Between 6 and cold eastern boundary currents in the they feed on , Euphausia superba, 11 months after birth, and at a length of North Pacific and North Atlantic Oceans which occurs in dense near-surface 12 m, the immature fin whale is weaned and in Antarctic waters of the Southern schools (Nemoto, 1959). In the North (Best, 1966; Gambell, 1985). The mean Hemisphere. They are most abundant in Pacific, E. pacifica, Thysanoessa calving interval for fin whales is 2.7 offshore waters where their primary inermis, T. longipes, and T. spinifera are years, with a range of between 2 and 3 prey (e.g. euphausiids) is concentrated the primary prey items. In the North At- years (Agler et al., 1993). in dense shoals. lantic, Meganyctiphanes norvegica and T. Natural Mortality Fin whales may have a significant inermis are consumed (Nemoto,1959). impact on marine ecosystems. As an There is some speculation, because of The causes of natural mortality in fin example, the total annual (spring and the sharing of the Antarctic krill resource whales are poorly understood. Despite summer) prey consumption by fin between both whale and nonwhale preda- harboring many endoparasites, it is only whales along the northeast U.S. conti- tors, that interspecific competition may be the giant nematode, Crassicauda nental shelf has been estimated at a critical factor in the biology of South- boopis, that appears to be pathogenic 664,000 tons per year (Hain et al., ern Hemisphere fin whales (IWC, 1992a). (Lambertsen, 1986; 1992). The inflam- 1992). By biomass, fin whales in this However, there is no direct information mation of the renal arteries and poten- area probably consume more food than on how such ecosystem level interactions tial kidney failure, which infestations of any other cetacean species. It is assumed may or may not affect the status of ba- C. boopis cause, may be a factor in lim- that fin whales undergo a partial or com- leen whales (Kawamura, 1994; Clapham iting the recovery of some fin whale plete fast while traveling to lower lati- and Brownell, 1996; Clapham and stocks (Lambertsen, 1992). tudes in the fall and throughout the win- Brownell6). Murphy et al. (1988) and Presumably killer whales rarely prey ter (Mizroch et al., 1984b). Fraser et al. (1992) suggest that competi- on fin whales. If such attacks do occur, The predominant prey of fin whales tion among whales and other small krill they likely go undetected by humans, varies greatly in different geographical predators in the Antarctic ecosystem is thus accounting for the scarcity of areas depending on what is locally relatively low. information. Immature, ill, or very abundant (IWC, 1992a). For instance, old individuals may be subject to mor- Reproduction in the Northern Hemisphere they con- tality or serious injury from either killer sume schooling fishes, such as capelin, Age at sexual maturity for both sexes whale or shark attacks under certain Mallotus villosus; anchovies, Engraulis ranges from 5 to 15 years (Lockyer, circumstances. mordax; , Clupea harengus; and 1972). The average length at sexual Estimated annual rates of natural sandlance, Ammodytes spp. (Mitchell, maturity for both males and females is mortality are higher in mature females 1975a; Overholtz and Nicolas, 1979; approximately 17.2 m (Mitchell, 1974a; than mature males (Aguilar and Lockyer,

61(1), 1999 49 1987; Lockyer and Sigurjónsson83). Rea- ing et al., 1998), but the full range of sudden changes in direction or speed sons for this are speculative, but may be fisheries that may interact with fin (Edds and MacFarlane, 1987; Mac- due to reproductive stresses (Aguilar whales have not been thoroughly inves- Farlane77). In the waters off , and Lockyer, 1987). The generally ac- tigated (Blaylock et al.,1995). an area in which there is a high level of cepted natural mortality rate for adult One concern is the potential impact whale watching and recreational boat fin whales is 4%, with a range of 4Ð6% of overexploitation of fish stocks by activity, fin whales have been reported (Clark, 1982; de la Mare, 1985). This commercial fishery operations in the to reduce the duration of their surfac- rate may be higher in immature indi- North Atlantic. Fin whales are an inte- ing and to reduce the number of blows viduals of both sexes. gral part of the North Atlantic ecosys- per surfacing when whale-watching and tem (Hain et al., 1992), and several fish other vessels are nearby (Stone et al., Human-related Mortality species taken in commercial fisheries are 1992; Young84). However, there is also also fin whale prey (e.g. herring, mack- evidence of habituation to increased ves- Fisheries Interactions erel, etc.). Conversely, fin whales were sel traffic by the fin whales in these wa- There are no reports of fisheries-re- implicated in the decline of herring ters (Watkins, 1986). lated fin whale mortality in the North stocks on Georges Bank in the middle Noise disturbance from seismic explo- Pacific (Hill et al., 1997). However, and late 1970’s (Sissenwine et al., ration appears not to affect fin whales in Barlow et al. (1997) noted that a con- 1984). detectable ways. Noise pulses from air flict may exist in the offshore drift guns off Oregon did not result in a change Vessel Collisions gillnet fishery in California and . in fin whale vocalization rates when com- Serious injury or mortality caused by It is possible that ship strikes affect pared to periods prior to the onset of noise, entanglement in fishing gear may go all fin whale stocks, but because of their suggesting they were undisturbed by the undetected if fin whales swim away pelagic nature, they go unreported be- pulses (McDonald et al., 1993) carrying portions of the gear or if en- cause injured or killed animals do not Classification Status tanglements occur far from shore. How- strand. In U.S. waters of the North Pa- ever, fishermen report that large blue cific, one death due to ship collision was The fin whale was listed as endan- and fin whales usually break through reported in 1991 (Barlow et al., 1997). gered under the ESA in 1973 and is pro- nets without entangling and with very In U.S. waters of the North Atlantic, tected under the MMPA. Endangered little damage to the net (Barlow et al., there are nine records of ship collisions, status is applied to all stocks in U.S. 1997). boat strikes, or propeller scars between waters (Anonymous, 1994a). Interna- In U.S. North Atlantic waters, there 1980 and 1994 (Blaylock et al., 1995) tionally, the North Pacific, Nova Scotia, were no reported mortalities from fish- and four such records between 1991 and West Norway/Faeroe Islands, and eries activities from 1989 to 1993, but 1995 (Waring et al., 1998). In 1996, one Southern Hemisphere stocks are clas- an entanglement database maintained anecdotal incident was reported from sified as “Protected Stocks” by the IWC. by the NMFS Northeast Regional Of- the southeastern of a Under this designation, the IWC recog- fice from 1975 to 1992 includes nine whale being hit at sea by a container nized that these whales are 10% or more occasions of fishing gear entanglement. ship and carried into harbor on the ship’s below their maximum sustainable yield Two of these entanglements resulted in bow (Kreuger, 1996). (MSY) levels, and therefore commer- known death to the whales, five of the cial whaling is prohibited (IWC, Noise Disturbance whales were recorded trailing fishing 1995b). The East Greenland/Iceland line of an unspecified source, and three Studies have shown that fin whales stock is classified as a “Sustained Man- were entangled in lobster-pot line respond to noise created by approach- agement Stock” (SMS) by the IWC. (Blaylock et al., 1995). In a review of ing vessel traffic in a variety of ways, This SMS designation indicates these 1992Ð96 data from this same NMFS depending on the behavior of the ani- whales are not more than 10% below database, an additional three whales had mals at the time of approach and the and not more than 20% above their net and rope marks or had line wrapped speed and direction of the approaching MSY levels. Whaling is permitted un- around mouth and tail, suggesting fish- vessel. Fin whales involved in feeding der this classification under advice of ery interactions (Waring et al., 1998). react less rapidly and with less obvious the Scientific Committee and in the ab- The total mortality and serious injury avoidance maneuvers than those not sence of a moratorium on whaling from North Atlantic fisheries-related involved in feeding (Richardson et al., (IWC, 1995b). The remaining stocks— incidents is considered biologically in- 1995). In the St. Lawrence River estu- West Greenland, Newfoundland/Labra- significant with regard to their estimated ary, summering fin whales encounter dor, British Isles/Spain and Portugal, PBR level37 (3.4 whales per year, War- heavy recreational and commercial ves- sel traffic from several sources (i.e. in- 84 Young, N. M. 1989. Dive and ventilation pat- 83 Lockyer, C., and J. Sigurjónsson. 1992. dustrial freight, whale watching). In the terns correlated to behavior of fin whales, Author’s summary of SC/F91/F8: The Icelandic St. Lawrence River, the most marked Balaenoptera physalus, in Cape Cod and Mas- fin whale, (Balaenoptera physalus): biological sachusetts Bays (Abstr.). In Proceedings of the parameters and their trends over time. Annex F. reactions to these vessels occurred when Eighth Biennial Conference on the Biology Ma- Rep. Int. Whal. Comm. 42:617-618. boats made fast, erratic approaches or rine Mammal, Dec. 1989, Pacific Grove, Calif.

50 Marine Fisheries Review Table 14.—Factors possibly influencing the recovery of North Atlantic fin whale stocks under the ESA (1973) ¤4(a)(1), 1992 Amend. (Southern Hemisphere data are not available).

Factor North Pacific Western North Atlantic1 Eastern North Atlantic2

1. Present or threatened destruction Offshore oil and gas development Unknown Unknown or modification of habitat

2. Overutilization for commercial, sub- Unknown Whale watching, scientific research, photography, and Icelandic harvest sistence, recreational, scientific, or associated vessel traffic; West Greenland harvest educational purposes

3. Disease or predation Unknown Giant nematode, C. boopis, infestations Giant nematode, C. boopis, infestations

4. Other natural or man-made factors Vessel collisions Vessel collisions; incidental take (e.g. gillnets, lobster pots, Unknown seines, fish weirs); human depletion of fish stocks

1 Nova Scotia, Newfoundland/Labrador, West Greenland. 2 East Greenland/Iceland, North Norway, British Isles/Spain and Portugal. and North Norway—have no formal fecting the status of fin whales are sum- ria. A joint Recovery Plan has been de- IWC classification; however, their catch marized in Table 14. At this time, any veloped for both fin and sei whales limits will remain at zero as long as the reevaluation of fin whale status awaits the (Anonymous7). This plan attempts to out- current moratorium on commercial collection of more reliable information on line steps towards recovery of the fin whaling is in place. stock structure, distribution and migration whale through focused research priorities Since Braham’s 1991 status review3, patterns, trends in abundance, causes of designed to increase our understanding of there has been little additional informa- mortality, and factors influencing the re- current threats, alleviate the possibility of tion regarding fin whale abundance or covery of fin whale stocks, as well as the future threats, and encourage international stock identity. The factors possibly af- development of objective delisting crite- cooperation.

61(1), 1999 51