160 EIGHTH PACIFIC SCIENCE CONGRESS 



limits of any nation. They spawn in the open sea far from land, the 

 juvenile stages require no littoral nursery grounds, and the adults are 

 completely oceanic in their foraging. Such knowledge of their move- 

 ments and aggregations as we have, indicates that they are oriented to 

 the water masses and currents of the ocean rather than to any geo- 

 graphical feature per se. The fisheries which harvest them are, for the 

 most part, completely oceanic; nearly all of the catch is made well out- 

 side the territorial limits of any nation. 



The Inter-American Tropical Tuna Commission 



Under accepted concepts of freedom of the seas, and free access to 

 the resources thereof, the tunas are truly an international resource, and 

 their scientific investigation and conservation is an international prob- 

 lem. Being cognizant of the need for adequate knowledge of the re- 

 source on which the tropical tuna fishery is based, the governments of 

 the United States of America and the Republic of Costa Rica in 1950 

 entered into a Convention establishing an Inter-American Tropical Tuna 

 Commission having as its objectives gathering and interpretation of 

 factual information to facilitate maintaining the populations of yellow- 

 fin and skipjack tunas, and of other fishes taken by tuna fishing vessels 

 in the Eastern Pacific Ocean, at a level which will permit maximum 

 sustained catches year after year. The Convention provides for the 

 subsequent adherence of any other nations having a mutual interest 

 in these fish populations. 



The Commission employed a scientific staff and initiated its in- 

 vestigations in January 1951. Headquarters are maintained at the 

 Scripps Institution of Oceanography, with which the Commission's staff 

 works in close co-operation. A regional office at Puntarenas, Costa Rica, 

 has also been established for the study of the biology and ecology of 

 bait fishes. 



The scientists of the Commission have a unique opportunity to 

 study the dynamics of an important commercial fishery during the 

 period of its growth and development. Fortunately, suitable statistical 

 and other records have been maintained to measure the changes in 

 catch and abundance of the tunas during the period of greatest growth 

 and development of the fishery from 1931 to the present time. This 

 is an unusual and most fortunate situation. Most often in the past, 

 little interest has been evinced in the investigation of commercial 

 marine fisheries, particularly those of an international character, until 

 the fishery has become so intense that economic distress of the industry 

 has demanded remedial measures. This has most often been so long 

 after the period of underfishing that suitable biological statistics for the 



