CHAPTER V 
MARINE MAMMAL-FISHERIES INTERACTIONS 
Marine mammals are taken incidentally in fisheries such 
as the yellowfin tuna purse seine fishery, are responsible 
for gear damage, fish damage, and fish loss in fisheries 
such as the salmon gillnet fishery and, in areas such as the 
Bering Sea, compete with fishermen for fish such as pollack. 
Commission overview and actions with respect to the incidental 
take of marine mammals during commercial tuna fishing operations 
is discussed elsewhere in this report. The following discussions 
describe Commission efforts to identify and deal with problems 
concerning marine mammal-caused gear damage, fish damage, 
and fish loss, and competition between marine mammals and 
fishermen for the same fish resources. 
Marine Mammal-Caused Gear Damage, 
Fish Damage, and Fish Loss 
Prior to passage of the Marine Mammal Protection Act, 
sport hunting, bounty hunting, and various forms of harassment 
were used to control the distribution, abundance, and/or 
behavior of certain marine mammals so as to eliminate or 
reduce gear damage, fish damage, and fish loss caused by 
Marine mammals. The Act imposed a moratorium on such taking 
and, in recent years, there have been reports that populations 
of harbor seals and other marine mammals are increasing and 
that there has been a corresponding increase in the amount 
of damage caused by marine mammals. 
Most of the reports of increasing marine mammal populations, 
gear damage, etc., have been from the Pacific Northwest and, 
in December 1977, the Commission convened a workshop to 
gather and review information concerning the nature and 
extent of possible marine mammal-fishery conflicts in Oregon, 
Washington, and Alaska (see p. 9 of the Commission's Annual 
Report for 1977). The workshop participants concluded that 
available information was insufficient to determine the 
precise extent and effects of apparent marine mammal-fishery 
conflicts in the Pacific Northwest, noted that conflicts 
appeared to be particularly severe on the Columbia River and 
in the Copper River Delta/Prince William Sound area of 
Alaska, and recommended, among other things, that appropriate 
methodology be developed and studies initiated to determine 
the levels of incidental take, gear damage, etc., on the 
Columbia River and in the Copper River Delta. 
3 SES 
