Chapter III — Species of Special Concern 
cance of the estimated bycatch, and (3) evaluate 
possible means such as season and area closures to 
reduce bycatch. The Commission also noted that if 
study objectives are met, proposed research will pro- 
vide a substantial amount of the information needed to 
begin implementing the Service’s proposed regime to 
govern interactions between marine mammals and 
commercial fisheries in the northeast and mid-Atlantic 
regions. The Commission also noted, however, that 
sufficient information was not provided to judge 
whether the objectives could be met in 1993. 
At the end of 1992, the Commission had not been 
advised as to the levels of funding to be allocated to 
implement these proposals or whether funding would 
be adequate to meet the stated research objectives. 
Harbor Porpoises off California, 
Oregon, Washington, and Alaska 
As discussed in past annual reports, concern has 
been raised over the status of harbor porpoises in 
waters off the central coast of California and the 
coasts of Oregon, Washington, and Alaska. 
As noted above, on 12 February 1991 the Service 
announced that it would review the status of harbor 
porpoises throughout U.S. waters. On 24 May 1991 
the Service published a follow-up notice stating that it 
had determined that there is no information available 
to indicate that harbor porpoises off the west coast of 
the United States are below their optimum sustainable 
population level, and it was therefore terminating that 
portion of its status review. 
In its June 1991 draft legislative environmental 
impact statement on its proposed regime to govern 
interactions between marine mammals and commercial 
fishing operations, the Service noted that harbor 
porpoise populations off the west coast of North 
America may be at optimum sustainable population 
levels, but that their susceptibility to incidental take in 
coastal gillnet fisheries is nonetheless a cause for 
concern. The Service therefore proposed that actions 
be taken to protect local harbor porpoise populations. 
On 23 September 1991 the Marine Mammal 
Commission wrote to the Service regarding the draft 
75 
environmental impact statement, noting that (1) the 
Service’s proposed regime to manage interactions 
between marine mammals and commercial fishing 
operations was intended to ensure that no marine 
mammal population would be adversely affected by 
levels of take authorized under the regime, and 
(2) this premise appears to be violated with respect to 
harbor porpoises because the best available data 
indicate that there is a relatively discrete population of 
harbor porpoises in central California that may have 
been depleted as a result of incidental take in set net 
fisheries. The Commission therefore recommended 
that the Service consider the possibility that incidental 
take has lowered the population density of harbor 
porpoises in localized areas. For further discussion of 
the Service’s proposed regime, see Chapter II. 
As noted above, on 23 October 1992 the Service 
asked the Commission to review and provide com- 
ments on marine mammal research proposals submit- 
ted by its regional science centers. Two proposals 
were for studies of harbor porpoises off the west coast 
and in Alaska. The objective of the proposed Alaska 
study is to obtain minimum population estimates of 
harbor porpoises in Alaska coastal waters. The 
Commission, in its 3 December 1992 letter to the 
Service commenting on the proposals, noted that the 
proposal indicates that harbor porpoises are commonly 
caught incidentally in commercial and subsistence 
fisheries in Alaska, but that the nature and magnitude 
of the incidental take are unknown. However, the 
proposal does not indicate what is being done, nor 
does it propose any steps to document the nature and 
magnitude of the incidental take. The Commission 
also noted that certain assumptions are made in the 
proposal that (1) there is no significant annual varia- 
tion in the distribution or abundance of harbor por- 
poises in the seven distinct coastal areas to be sur- 
veyed, and (2) all harbor porpoises in Alaska coastal 
waters are part of the same population and are not 
subject to significant incidental take or other non- 
natural sources of mortality outside of Alaska coastal 
waters. The Commission further noted that if the 
validity of the aforementioned assumptions has not 
been verified, the population estimate likely to be 
obtained from past and proposed surveys may be 
insufficient. The Commission therefore recommended 
that before providing additional funds for this pro- 
gram, the Service ensure that the data needs have 
