MARINE MAMMAL COMMISSION - Annual Report for 1995 



Northern Right Whale 

 (Eubalaena glacialis) 



The northern right whale occurs in both the North 

 Atlantic and North Pacific Oceans and is the world's 

 most endangered large cetacean. Right whales, the 

 first of the great whales to be targeted by a regular 

 whaling industry, have been exploited since at least 

 the 1 1th century along the coast of present day France 

 and Spain, and at least the 1600s in Japan. By the 

 late 1800s northern right whales were commercially 

 extinct in both oceans. Even so, whalers seeking 

 other species continued to take right whales opportu- 

 nistically until the mid- 1900s pushing the species to 

 the edge of extinction. 



Although small populations of northern right 

 whales survive in both the North Atlantic and North 

 Pacific Oceans, their numbers are so small that their 

 continued existence is in serious doubt. In the North 

 Pacific Ocean, catch records and sighting data suggest 

 that right whales in the eastern and western parts of 

 the ocean basin constitute separate stocks. Because 

 sightings in the eastern North Pacific over the past 20 

 years are so few and include neither groups of animals 

 nor a single calf, the present generation could well be 

 the last generation for eastern North Pacific popu- 

 lation. Sighting records from the western North 

 Pacific Ocean and Okhotsk Sea, while scarce, are 

 more numerous than in the eastern North Pacific. As 

 they also include some sightings of groups, it seems 

 possible that the western North Pacific population may 

 still number in the low hundreds. 



In the North Atlantic Ocean, between 300 and 350 

 whales occur seasonally off the east coasts of the 

 United States and Canada. Rare sightings also occur 

 off Greenland, Iceland, Europe, and northwest Africa. 

 These could represent either remnants of an eastern 

 North Atlantic population or stragglers from the 

 western North Atlantic. Since 1980 an average of 10 

 to 12 calves per year have been counted along the 

 U.S. and Canadian coasts making the species' pros- 

 pects for recovery in the North Atlantic Ocean tenu- 

 ous, but still brighter than in the North Pacific Ocean. 

 For the years 1993 to 1995, however, the number of 

 calves counted declined to 6, 9, and 7, respectively. 



Although international laws banning commercial 

 hunting of right whales have been in place for about 

 50 years, ship collisions, entanglement in fishing gear, 

 and perhaps other human activities threaten the 

 species' potential recovery. Between 1970 and the 

 end of 1995 more than one-third (13 of 35) of all 

 right whale carcasses found along the east coast of 

 North America died from apparent human-related 

 causes. Ten deaths (29 percent) are attributed to 

 collisions with ships and three (9 percent) to entangle- 

 ment in fishing gear. Analyses of identifiable right 

 whales in a photographic catalogue of the North 

 Atlantic population suggest that more than half of the 

 population has scars or are trailing line indicative of 

 entanglement interactions, and that seven percent has 

 scars apparently from ship collisions. 



Observed carcasses represent an unknown percent- 

 age of total northern right whale mortality. However, 

 it seems likely that at least as many deaths have gone 

 unrecorded. Between 1980 and 1995 researchers 

 documented 175 calves in the western North Atlantic 

 and confirmed 26 deaths. Analyses of data in a right 

 whale photo-identification catalogue have suggested an 

 annual population growth rate of 2.5 percent which, 

 assuming a current population of 325 animals, would 

 equal an increase of about 100 animals since 1980. If 

 this growth rate is correct and if all calves in the 

 population were recorded since 1980, about 75 deaths 

 have occurred since 1980, of which only about one- 

 third (26 of 75 carcasses) have been documented. 

 The proportion of unrecorded deaths could be even 

 greater if estimated 2.5 percent growth rate is high or 

 some calves are not counted. If the causes of death 

 for documented carcasses are representative of total 

 mortality, deaths due to ship collisions and entangle- 

 ment could be three times or more greater than 

 documented levels. 



Other potential human threats to the species include 

 disturbance and displacement of whales from seasonal- 

 ly important habitat by noise and human activity, prey 

 reduction caused by perturbations to local environ- 

 mental conditions in preferred feeding grounds, 

 physiological impacts caused by chemical pollutants, 

 and entanglement and ingestion of marine debris. 

 Specific human activities that could contribute to one 

 or more of these impacts include discharges by 

 municipal sewage and storm-water outfalls, offshore 



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