FORTY-SECOND BIENNIAL REPORT 67 



San Francisco and very little off Monterey. In 1951-52 the entire Cali- 

 fornia fishing fleet moved to Southern California waters. The catch 

 from this area was largely processed by the southern plants although 

 small tonnages were trucked to San Francisco and considerable amounts 

 to Monterey. 



The numbers of sardines taken by locality and age group were com- 

 piled for the 1950-51 and 1951-52 seasons and published in the July, 1951 

 and July, 1952 issues of California Fish and Game. 



TUNA 



The industry faced a period of general uncertainty during the bien- 

 nium. The increasing competition of canned tuna from foreign sources 

 and increasing domestic production drove processors' inventories to high 

 levels at times, and forced processors to reduce the rate of delivery of 

 raw fish by the fishing fleet. The situation was further complicated by 

 the processors' purchase of raw fish from foreign sources. Seriously 

 concerned, all components of the industry united in an effort to effect 

 the increase of the tariff on canned tuna in brine and to impose an import 

 duty on raw fish. 



Price at the end of the biennium was $350 per ton for albacore, $320 

 per ton for yellowfin tuna and $260 per ton for skipjack. 



The tuna fleet, especially the larger vessels, expanded southward in 

 the latter part of 1951 to new fishing grounds off the coast of Ecuador. 

 Further expansion southward was blocked by the policy of the Govern- 

 ment of Peru which does not permit American vessels to fish in Peruvian 

 waters. 



The research program was revised and augmented during the period. 

 During the earlier part of the biennium, new publications presented 

 further evidence that the yellowfin tuna populations of the Eastern 

 Pacific and the Central Pacific are separate nonintermingling stocks, 

 and that the Australian, California and New England bluefin tuna are 

 probably separate species. In the latter part of the biennium, programs 

 were inaugurated to determine : 



a. The age and rate of growth of Eastern Pacific yellowfin tuna, skip- 

 jack, and albacore (Neothun»us macropterus, Katsutvonus pelamis, 

 Thunnus germo). 



b. The age composition of the commercial catch of yellowfin tuna, 

 skipjack, and albacore. 



c. Study of the migration pattern, if any, of yellowfin tuna, skipjack, 

 and albacore by means of marking. 



d. Proper level for exploitation of yellowfin tuna by analysis of the 

 catch-effort relationship. 



It appears, from recoveries of tagged yellowfin tuna, that a successful 

 tag for the tunas has been developed, and the investigation is undergoing 

 the transition from experimental tagging to a large-scale effort to deter- 

 mine migration by means of tags. The tag is a piece of vinylite plastic, 

 about the diameter of a piece of spaghetti, attached to the fish by a loop 

 through the tissue of the back, just posterior to the second dorsal fin. 



