Laevastu, T. , and I. Hela. 1970. Fisheries oceanog- 

 raphy. Fish. News (Books) Ltd., Lond . , 238 p. 



A compilation of fish-environmental rela- 

 tions, summarizing the state of knowledge in 

 the field and giving examples of the inter- 

 actions between fish and their environment. 

 Wide geographic coverage considering several 

 types of fishes. 



KEY WORDS: tuna, distribution, environment. 



Laevastu, T. , and H. Rosa, Jr. 1963. Distribution and 

 relative abundance of tunas in relation to their 

 environment. In H. Rosa, Jr. (editor). Proceed- 

 ings of the world scientific meeting on the biol- 

 ogy of tunas and related species. La Jolla, Cali- 

 fornia, U.S.A., 2-14 July 1962, p. 1835-1851. FAO 

 Fish. Rep. 6. 



Tabulated the temperature range of each 

 species of tuna and indicated the optimum 

 temperature range for fisheries. Temperate 

 water species (albacore and bluefin) season- 

 ally migrate according to temperature con- 

 trol, food, or both. High concentrations oc- 

 curred when there were high surface tempera- 

 ture gradients and where the optimum tempera- 

 ture zone was narrow. Also a vertical tem- 

 perature gradient could act as a barrier and 

 cause aggregation. Thermocline ridges were 

 preferred areas for aggregation. They noted 

 that Japanese work indicated that several 

 species usually remain within a given current 

 or water mass for a season, then migrate from 

 one water mass to another during seasonal 

 changes. Within a water mass or current 

 tunas tended to aggregate at boundaries. 

 Eddies were preferred sights for aggregation 

 along with frontal zones. Transparency 

 values of 25-35 m were optimal for best 

 fishing. Fishing areas coincided with pro- 

 ductive areas. Migrations were discussed 



KEY WORDS: 

 jack, bigeye 

 ature, depth 



tunas, bluefin, yellowfin, skip- 

 , albacore, distribution, temper- 

 , currents, transparency, food. 



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