This number constitutes a very substantial reduction from 
the mortality levels for 1977 and previous years. For 
reference, figures for the estimated porpoise mortality and 
serious injury associated with U.S. tuna fishing vessels 
since passage of the Act are set forth below. 
Year Estimated Kill and 
Serious Injury 
1972 368,600 
1973 206,697 
1974 Ana Sih 
1975 166,645 
1976 108,740 
1977 25,452 
1978 19,366 
1979 17,938 
1980 13,000-15,000 
Regulations for the 1981-1985 Fishing Seasons 
In an effort to develop and evaluate the best scientific 
information available concerning the status of the affected 
porpoise populations for consideration in the course of 
hearings to develop regulations and quotas for the 1981 and 
subsequent fishing seasons, the National Marine Fisheries 
Service convened a workshop of experts in population 
dynamics, with special emphasis on large mammals. Repre- 
sentatives of the Commission participated in the Workshop 
which was held in August 1979 at the Southwest Fisheries 
Center in La Jolla, California. The Report on the Workshop, 
published in November 1979, set forth the conclusions of 
the participants that, among other things, the estimated 
abundances of the affected porpoise populations in 1979 were 
substantially lower for most stocks than was estimated in 
the 1976 Workshop and proceedings which formed the basis 
of the quotas for the 1978-80 fishing seasons. The Report 
indicated that the reduced size of stocks should not be 
construed to be an indication of large stock decreases 
between 1976 and 1979 but, rather, to be a result of a new 
and improved estimation procedure and better information. 
A particularly significant conclusion of the participants 
was that the abundance of the northern offshore spotted 
porpoise population was only between 34 and 55 percent of its 
initial, pre-exploitation level, depending upon which of 
several alternative assumptions were made, and that the present 
level is below what the participants felt was the lower bound 
of the range of optimum sustainable population levels. 
The significance of those conclusions resulted from the fact 
that if the northern offshore spotted population were found 
= 49, = 
