6. Johnson, J. H. -Sea temperatures and the availability of albacore (Thunnus 



germo) off the coasts of Oregon and Washington 



7. Uda, M. - Cyclical fluctuation of the Pacific tuna fisheries in response to cold 



and warm water intrusions 



8. Uda, M. - Localized concentration of tunas in the eddies along oceanic fronts 



9. Austin, T. S. , and R. A. Barkley - Use of oceanographic stations in fishery 



research 



10. Seckel, G. R., and T. S. Austin - The association between Hawaiian skipjack 



landings and the oceanographic climate 



11. Brown, R. P., and K. Sherman - Oceanographic observations and skipjack dis- 



tribution in the North Central Pacific 



In the past, and to a lesser extent at 

 present, only a knowledge of the broad -scale 

 oceanographic features was needed to study the 

 distribution of tunas . Our present need for more 

 detailed knowledge of both the horizontal and ver- 

 tical distribution of tunas requires a more de- 

 tailed knowledge of oceanographic features and 

 the processes involved. Two aspects of tuna 

 oceanography can be considered: (1) distribution, 

 population size, and environme nt of tunas, and 

 (2) prediction techniques using oceanographic 

 data. 



On a worldwide basis there is need for 

 more information concerning the distribution of 

 the different tunas. Exploitation of new fishing 

 grounds and extensive exploratory fishing, to- 

 gether with re -examination of taxonomic prob- 

 lems, requires continued evaluation and revision 

 of charts showing distribution. Parathunnus 

 obesus probably occurs in the western as well as 

 the eastern Atlantic; Euthynnus lineatus has a 

 continuous distribution in the eastern Pacific 

 within the limits shown; and both Sarda chilensis 

 and S. orientalis occur in the eastern Pacific, 

 with a break in the distribution between about 

 latitudes 7° N. and 15° N. Suggestions as to the 

 distribution of the different species would aid in 

 the completion of a world distribution paper being 

 prepared by FAOfor the World Tuna Conference 

 in 1962. 



In the western half of the Pacific, tem- 

 perature -chlorinity curves for the upper 200 

 meters were useful in identifying water mass 

 subtypes and the associated distribution of tunas 

 andmarlins. Water mass characteristics, iden- 

 tified by temperature -salinity relationships, are 

 useful not only on an oceanwide basis, but also 

 for studies within the area of a fishery. There 

 is need for some means of portraying 

 temperature-salinity relationships as a single 

 index of water type on a time -space basis. An 



approach worth considering would be the use of 

 the discriminant function analysis. However, 

 since temperature and salinity, as measured at 

 the sea surface , are not conservative properties, 

 it appears necessary to isolate the conservative 

 portion of each, i.e., that portion not due to 

 sea-atmosphere interaction processes at the sea 

 surface. 



Availability and abundance of tunas are 

 related in various ways to different aspects of 

 temperature in the ocean. Processes in the at- 

 mospheric pressure system exert an influence 

 on the temperature distribution in the ocean. 

 Skipjack, albacore, and bluefin tuna in the west- 

 ern and eastern Pacific show certain variations 

 in abundance and availability which may be 

 temperature-controlled. Cyclical changes in 

 catch and temperature in the western and east- 

 ern Pacific appear to vary in a reciprocal man- 

 ner. The proposed reciprocal relationship, 

 particularly with respect to a potential prediction 

 technique, should consider the total American 

 west coast landing s of albacore. The reciprocal 

 trend in temperature has been observed in data 

 from monitoring stations. Commerical catch 

 records show that in some years the reciprocal 

 trend in catch does not pertain, i.e., there may 

 be good catches in both the American and the 

 Japanese fisheries. However, caution must be 

 exercised in using commercial catch records 

 because of changes in the economics and tech- 

 nology of a fishery. As an example, the poor 

 albacore catch off Oregonand Washington in 1957 

 can be accounted for by a glut of this tuna in the 

 American and world market, resulting in a 

 dearth of buyers for American albacore. 



A study of the possible influence of the 

 waters of the Equatorial Countercurrent in sta- 

 bilizing the biota and environment in the eastern 

 Pacific yellowfin and skipjack fisheries would 

 be valuable. 



