Morita, T. 1960. Studies on the constitutional state 

 of skipjack fishing ground over the waters near 

 Tokara Retto (I). On the relation between the 

 water-temperature and the catching condition in 

 the fishing ground. [In Jpn . , Engl, summ.] Mem. 

 Fac. Fish, Kagoshima Univ. 8:121-129. 



Seasonal changes in fishing grounds off Japan 

 were related to vertical oceanographic struc- 

 ture and seasonal stock migrations. 



KEY WORDS: tuna, skipjack, oceanography, 

 catch, season, temperature, depth. 



Murphy, G.I., and R.S. Shomura. 1972. Pre-exploi ta- 

 tion abundance of tunas in the equatorial central 

 Pacific. Fish. Bull., U.S. 70:875-913. 



Related temperature, upwelling, nutrients, 

 and forage to ocean processes and to tuna 

 distributions. Considered the hypothesis 

 that variations in yellowfin are influenced 

 by variations in the wind-driven ocean circu- 

 lation that affects the food supply of the 

 species . 



KEY WORDS: tunas, yellowfin, skipjack, big- 

 eye, albacore, temperature, enrichment, 

 fronts, wind, convergence, currents, oceanog- 

 raphy. 



57 



