KLEIBER and BAKER: INTERACTION BETWEEN NORTH PACIFIC ALBACORE FISHERIES 



a completely overlapping, competing fleet. The 

 response of each fleet to doubling of its own effort 

 was close to a 1009f increase in catch (Tables 2, 3), 

 indicating that the degree of competition was low. 

 Therefore, it would be difficult to design a realis- 

 tic experimental treatment that 1) would be sim- 

 ply a shift in the geographic and seasonal pattern 

 of effort in one fleet (not a change in magnitude), 

 and 2) would have a strong impact on another 

 fleet. 



A legitimate question is whether our conclu- 

 sions, which are based on 1970s data, can be ex- 

 trapolated to the current conditions. The most 

 striking change in recent years is the emergence 

 of the gill net fishery for albacore, which now 

 takes approximately 207f of the total catch. How- 

 ever, because the total catch has not increased, 

 the exploitation rate must still be mild, and we 

 would expect that interaction between fleets 

 would also still be mild. We cannot use our model 

 to estimate interaction quantitatively in this sit- 

 uation because we lack detailed data on the gill 

 net fishery. 



CONCLUSIONS 



The implication of our results is that fleet inter- 

 action is not likely to be significant if the pattern 

 and magnitude of effort in the 1970s are main- 

 tained. This assessment could change if the over- 

 all exploitation rate increases considerably. The 

 recent emergence of the gill net fishery could be of 

 significance in this regard. The levels of annual 

 catch that have been reported by this fishery are 



not likely to be of concern, but the significance 

 cannot be confidently evaluated unless detailed 

 catch, effort, and size distribution data are made 

 available. 



LITERATURE CITED 



Clemens, H. B. 



1961. The migration, age, and growth of Pacific albacore 

 (Thunnus germo), 1951-1958. Calif. Dep. Fish Game, 

 Fish. Bull. 115, 128 p. 



Kearney, R E 



1983. Assessment of the skipjack and baitfish resources in 

 the central and western tropical Pacific Ocean: Summary 

 of the Skipjack Survey and Assessment Pro- 

 gramme. South Pacific Commission, Noumea, New 

 Caledonia, 37 p. 



Jones. R 



1981. The use of length composition data in the fish stock 

 assessment (with notes on VPA and cohort analy- 

 sis). FAO Fish Circ. 734, 55 p. 



Laurs, R M 



1983. The North Pacific albacore — An important visitor 

 to California Current waters. Calif. Coop. Oceanic Fish. 

 Invest. Rep. 24:99-106. 



Laurs, R M., W H Lenarz, and R. N. Nishimoto. 



1976. Estimates of rates of tag shedding by North Pacific 



albacore, Thunnus alalunga. Fish. Bull., U.S. 74:675- 



678. 

 Nishikawa, Y . M Honma. S Ueyanagi, and S Kikawa 



1984. Average distribution of larvae of oceanic species of 

 scombroid fishes, 1956-1981. Far Seas Fish. Res. Lab., 

 Jpn., Contrib. No. 236, 99 p. 



SUDA. A. 



1966. Catch variations in the north Pacific albacore- VI. 

 The speculations about the influences of fisheries on the 

 catch and abundance of the albacore in the north Pacific 

 by use of some simplified mathematical models. Rep. 

 Nankai Reg. Fish. Res. Lab. 24:1-14. 



711 



