July 1966 



COMMERCIAL FISHERIES REVIEW 



53 



tions and their changes from late spring to 

 mid-summer. The success in foretelling 

 time of commencement of the fishery has, 

 with the exception of last year (1965) been 

 reasonably good. 



The predictions of total landings for the 

 albacore and bluefin fisheries have not been 

 noteworthy, according to the laboratory staff. 

 During the past year, analysis of data relat- 

 ing to their previous forecasts has revealed 

 that until they are able to forecast the fluctu- 

 ations in year -class representation in the 

 North Pacific albacore and bluefin popula- 

 tions, and until economic conditions (and con- 

 sequently, fishing effort) can be predicted, they 

 will continue to score poorly. Studies on 

 year -class representation are being initiated 

 to correct this particular deficiency. 



The 1966 forecast carries three separate 

 estimates of: (1) where, (2) when, and (3) 

 how much tuna may be taken at the beginning 

 of and during the forthcoming season. The lab - 

 oratory staff was limited to making estimates of 

 items (1-3) for the Southern California-Baja 

 California offshore region for albacore, and 

 only item (3) for bluefin. 



(1) The area that is expected to produce 

 the best albacore fishing in July off Southern 

 California and Baja California is shown (see 

 chart). That area, derived from April IO- 

 meter temperature and salinity data, repre- 

 sents the "optimum area" that may produce 

 more than two -thirds of the total July catch. 

 Upwelling appeared to be about average for 

 the time of year, and albacore will probably 

 remain in blue water 20 miles or more off- 

 shore. 



(2) The open ocean in the region encom- 

 passing the m.igratory route of albacore ap- 

 peared to be warming only slightly faster 

 than average, indicating that the first fish of 

 the shoreward migration would probably ap- 

 pear in the first week of July. (Waters off 

 Oregon and Washington began to warm ap- 

 preciably from mid-April to mid-May. If 

 this trend were to continue uninterrupted, the 

 Pacific Northwest fishery should get off to a 

 good start late in July.) 



(3) It was estimated that July landings in 

 southern California would be below average. 

 This year, it was expected that about 8.6 nail- 

 lion pounds of albacore would be taken from 

 the region south of the U. S. -Mexico border, 

 and about 6.0 million pounds of bluefin to the 



north. (Average production for the period 

 1945-62 has been 14.2 million pounds of alba- 

 core and 7.7 million pounds of bluefin.) The 

 estimate for albacore reflects expected aver- 

 age to below-average representation of the 

 20- to 30-pound size-class and below average 

 numbers of the 10- to 15-pound size-class. 

 The estimates are based onthe poor showing of 

 10- to 15 -pound fish in California last season 

 (returning as 20-30 pounders this year), as 

 well as the absence of 6- to 8 -pound fish (re- 

 turning as 10-15 pounders this year). In ad- 

 dition, early season reports from the Japa- 

 nese spring pole-and-line fishery indicated 

 that the 10- to 15 -pound size -class was aver- 

 aging less in weight and fewer in number than 

 usual. This situation, along with other factors, 

 appears to have caused the Japanese fishery 

 interests to reduce their original landings 

 forecast from 45,000 to 30,000 metric tons. 

 Similar conditions were expected to prevail 

 for the California bluefin tuna fishery, be- 

 cause the incoming 10- to 15 -pound size -class 

 was not well represented last season and may 

 fail to return in sufficient numbers during 

 1966. 



In 1965, the laboratory's forecast for alba- 

 core landings south of the International Border 

 exceeded actual landings by 60 percent, and 

 bluefin landings to the north were overesti- 

 mated by about 62 percent. Probable causes 

 for those overestimates are: (a) year -class 

 representation in both fisheries appeared to 

 be poor in the small (10-15 pounds) and inter- 

 mediate-sized (20-30 pounds) length groups; 

 (b) high offshore winds and record cold weath- 

 er observed in southern California for late 

 May-early July delayed the onset of both fish- 

 eries by as much as 4-6 weeks. Consequent- 

 ly, when the boats did commence fishing, the 

 late start coupled with poor fish population 

 abundance caused landings to fall far short of 

 previous estimates. 



In 1965, U. S. West Coast albacore tuna 

 landings would have been among the poorest 

 on record if the Pacific Northwest fishery had 

 not materialized. Oregon-Washington landings 

 proved to be the best since 1948, and totaled 

 slightly over 14.0 million pounds. Consequent- 

 ly, the United States total came to 37.1 million 

 pounds, or 4.8 million pounds short of the 21- 

 year average. 



The staff of the Bureau's Tuna Forecasting 

 Program states that its understanding of the 

 normal progression of events during the fish- 

 ing season has improved in recent years, and 



