Trip report : porpoise population aerial survey of the eastern tropical Pacific Ocean January 22-April 25, 1979

The Marine Mammal Protection Act of 1972 charges the U.S. Department of Commerce, NOAA's National Marine Fisheries Service to monitor the status of porpoise stocks which are impacted by the Eastern Tropical Pacific (ETP) Ocean tuna purse seine fishery. In addition to mortality and reproductive rates, population size must be determined before a new assessment can be made. The mission of the 1979 aerial survey was to determine, according to line transect theory and aerial porpoise sighting observations, the total number of porpoise by stocks in the ETP. In this report, the procedures of the aerial survey and some of the data gathered during the survey are documented. 1980 NMFS (National Marine Fisheries Service) SWFSC (Southwest Fisheries Science Center) Library Public Domain 1930