FORTY-FIFTH BIENNIAL REPORT 



69 



TUNA 



The California tuna industry forged ahead during 

 the biennium, attaining record production levels. In- 

 creased advertising, price cuts on some items, and 

 favorable market conditions resulted in a larger con- 

 sumption of the product. 



However, the American fishermen's share of this 

 expanding market is becoming smaller each year and 

 prices are declining, while foreign imports continue 

 to increase. 



PACIFIC ALBACORE 



Since 1950, the eastern Pacific albacore fishery has 

 been limited almost exclusively to the ocean waters 

 oiT Baja California and California. During this bien- 

 nium, however, oceanographic conditions changed 

 markedly and the fishery expanded northward. As a 

 result, California landings included albacore caught all 

 the way from central Baja California to northern 

 Washington. 



The year 1950 was tops for the number of boats 

 landing albacore in California. During that year, 3,162 

 different vessels, not including skiffs, caught and de- 

 livered fish. Each following year many boats dropped 

 out and near the end of the biennium only 1,404 re- 

 mained in the fishery. 



Log Book System Pays Off 



Department scientists are making rapid progress 

 toward an ultimate goal of improving the fishery. The 

 new log book system, started experimentally and in a 

 limited fashion during the last biennium, has come of 

 age and is now standard. It is currently providing the 

 most complete picture of the west coast albacore fish- 

 ery ever compiled. It is now possible to determine 

 where and when about 25 percent of the fish landed 

 in California are caught and how many days of fishing 

 effort were required to catch them. 



In addition, the log books are yielding valuable in- 

 formation concerning the sea surface temperatures 

 that are the most productive. They have shown that 

 the heaviest catches of albacore were made within a 

 relatively narrow sea surface temperature range of 

 60-64 degrees F. This albacore catch-temperature re- 

 lationship should be of tremendous value for use in 

 locating areas most likely to produce good fishing. 



Exploratory Fishing Successful 



Two albacore research cruises were conducted 

 aboard department vessels during the last two years. 

 These cruises were designed to intercept incoming 

 albacore school groups prior to the start of the regular 

 commercial fishing seasons in June and to chart their 

 migration routes as they sweep in toward the west 

 coast of central Baja California and Southern Califor- 

 nia. In addition, oceanographic data were obtained 



throughout the survey areas in an effort to correlate 

 the apparent preference of albacore to travel along 

 certain paths. 



The results obtained from these cruises verified 

 seasonal data obtained by log book analysis concern- 

 ing the relationship between the catch of albacore and 

 sea surface temperatures. It was also found that major 

 coastward migrations occurred in that part of the 

 ocean where sea surface temperatures ranged between 

 60 and 65 degrees F. This means that when tempera- 

 ture data are available it is possible to predict likely 

 fishing areas before the season begins. Such informa- 

 tion will be of great economic value to fishermen in 

 the future, saving much time and expenses formerly 

 expended by the fleet in prospecting. 



CALIFORNIA BLUEFIN TUNA 



The wily bluefin tuna is more suspicious of hooks 

 than is its close relatives. Therefore, harvesting of this 

 marine resource is accomplished by means of large 

 purse seines. Purse seiners realize their largest catches 

 in the coastal waters between Point Conception and 

 southern Baja California and offshore near Guadalupe 

 Island. Warm sea temperatures during 1957 appar- 

 ently influenced their distribution and larger than 

 usual catches were made in the northern portion of 

 the range. In general, the fishing season begins in June 

 and ends by October although some catches are made 

 throughout the year in the Guadalupe Island area. 



Fluctuations in demand for the product characterize 

 the bluefin fishery in general, although catches tend 

 to be sporadic even with a steady demand. In spite of 

 this instability, landings reached high levels during the 

 last two years. 



Attention was focused on the bluefin problem early 

 in the biennium and plans made to increase research 

 returns on this species. As a result, basic catch data 

 concerning 80 percent of the total landings have been 

 obtained and there is now the most complete picture 

 of the West Coast bluefin fishery ever compiled. 



With this information gathered, an understanding 

 of the erratic catches should place the fishery on a 

 more stable yield basis. 



PACIFIC YELLOWFIN TUNA AND SKIPJACK 



These "tunas" prefer more tropical climes than do 

 albacore or bluefin tuna and are harvested the year 

 around in the tropical eastern Pacific by large Cali- 

 fornia-based tuna clippers capable of ranging far afield. 

 During the previous biennium these fishing vessels 

 operated offshore from southern Baja California south 

 to Peru, including the outlying banks and islands. 

 During the present biennium, however, some commer- 

 cial vessels cruised several hundred miles farther south 

 into inhospitable waters off the coast of Chile, while 

 others fished all >'ear off Baja California. The Chilean 



