MARINE MAMMAL COMMISSION — Annual Report for 1992 
Gulf of Maine; the salmon drift gillnet and set gillnet 
fisheries, both in Alaska waters and Puget Sound; and 
the swordfish and thresher shark drift gillnet and 
salmon troll fisheries off the coasts of Washington, 
Oregon, and California. Harbor porpoises are also 
taken incidentally in fisheries off the east and west 
coasts of Canada, and these animals may be from the 
same populations being affected by U.S. fisheries. 
The subcommittee on small cetaceans of the 
International Whaling Commission’s Scientific Com- 
mittee reviewed the incidental take of harbor porpois- 
es, and in a report issued in 1990, it concluded that 
the problem may exist wherever gillnet fisheries 
operate in proximity to harbor porpoises. It further 
noted that the level of incidental take may be especial- 
ly high in the North and Baltic Seas. Outside the 
United States, direct as well as incidental take of 
harbor porpoises has been significant in some areas. 
As noted in the previous annual report, a large-scale 
Turkish fishery for harbor porpoises operated in the 
Black Sea from 1976 until 1983 when the fishery was 
suspended (for further discussion of harbor porpoises 
in the Black Sea, see Appendix B, Buckland 1990). 
Currently, the only known directed fishery for harbor 
porpoises is in Greenland, where from 700 to 1,000 
animals are taken annually for local consumption from 
a total estimated population of 10,000-15,000. 
Harbor Porpoises in the Gulf of Maine 
and the Bay of Fundy 
In U.S. coastal waters, the number, size, discrete- 
ness, and productivity of harbor porpoise populations 
have not been well documented, making it difficult to 
judge whether levels of take have caused or are 
causing one or more populations to be reduced below 
their maximum net productivity level. 
In 1990 and again in 1991, the International 
Whaling Commission Scientific Committee’s subcom- 
mittee on small cetaceans recommended a number of 
research projects on harbor porpoises in the western 
North Atlantic. Specifically, the subcommittee 
recommended that research be undertaken to (1) im- 
prove understanding of harbor porpoise population 
discreteness; (2) estimate population abundance; 
(3) refine estimates of the magnitude of direct and 
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incidental take; (4) conduct a joint U.S.-Canadian 
comprehensive survey of the Gulf of Maine and Bay 
of Fundy; (5) address the degradation of coastal 
habitat; and (6) address the effects of contaminants on 
harbor porpoise populations. The subcommittee also 
recommended that levels of harbor porpoise mortality 
due to incidental take throughout their range be 
reduced by modifying or converting gear types or by 
implementing area or seasonal closures of certain 
fisheries. 
In December 1991 the National Marine Fisheries 
Service’s Northeast Fisheries Science Center published 
a report addressing harbor porpoise abundance in the 
Gulf of Maine and Bay of Fundy, based on the results 
of two at-sea surveys conducted in the summer of 
1991. Because of uncertainty as to the number of 
duplicate sightings of animals, the report presented 
two preliminary estimates of abundance: 66,000 
animals, based on the lower estimate of duplicate 
sightings, and 45,000 animals, based on the higher 
estimate. In either case, the number of harbor por- 
poises in the Gulf of Maine and Bay of Fundy was 
substantially higher than had been estimated. A previ- 
ous survey, conducted in 1981 by the New England 
Aquarium with the support of the National Marine 
Fisheries Service, resulted in estimates of between 
8,000 and 15,000 harbor porpoises along the coast of 
Maine. 
The Service’s 1991 report also provided a new 
estimate of the level of incidental take in Gulf of 
Maine sink gillnet fisheries. This estimate was 
derived from observations of incidental take by 
commercial groundfish gillnet vessels fishing in the 
Gulf from June 1989 through May 1991. During this 
period, observers were present on slightly more than 
one percent of fishing trips, and 34 harbor porpoises 
were observed to be taken. Preliminary estimates 
extrapolated from these data indicate that at least 
1,250 harbor porpoises were killed each year in the 
Gulf of Maine fishery. This represents about 2.8 
percent of the Northeast Fisheries Science Center’s 
lower population abundance estimate and about 1.9 
percent of the higher estimate. Previous estimates 
were much lower. 
During 1991 representatives of the National Marine 
Fisheries Service, the Canadian Department of Fisher- 
