standing of the relationships between environ- 

 mental conditions and infancy and egg survival for 

 many of the stocks. 



Science must come to understand the inter- 

 action of competitor-predator systems, the study 

 of the dynamics of multi-species systems under 

 predation. For example, the replacement of the 

 commercially important Pacific sardine by the less 

 valuable anchovy was apparently the combined 

 result of a highly selective fishery and natural 

 environmental change, the interactions of which 

 are not understood.' 



Better correlations between environmental con- 

 ditions and fish abundance, when accompanied by 

 better monitoring and prediction of those condi- 



Figure 10. Global scientific expedition 1967. 

 Modem oceanographic observations are utiliz- 

 ing complex electi-onic instiiAments such as 

 this salinity-temperature-depth sensor. Al- 

 though more costly than classical instruments, 

 these instruments portray more accuracy and 

 realistic measurement of the actual ocean 

 structure. (ESSA photo) 



Population Biology of Pacific Sardine (Sardinops 

 caerulea), Murphy, Proceedings of the California Acad- 

 emy of Sciences, fourth series. Vol. 34, No. 1, July 1966; 

 numerous publications of the California Cooperative 

 Fishery Investigations (Cal. COFI). 



tions, should enable fishermen to work more 

 productively and efficiently. 



"New fisheries" are defined as those involving 

 the harvesting either of species previously not 

 exploited or of previously untouched stocks of 

 species that are fished elsewhere. The most urgent 

 requirement for scientific information in the case 

 of a new fishery is for rapid means of stock 

 assessment. There must be determinations of 

 abundance, susceptibility to existing fishing tech- 

 niques, and, for effective continued use, maximum 

 sustained yield. Exploratory fishing may reveal 

 potentially exploitable stocks, but basic studies in 

 population dynamics are necessary to evaluate the 

 long term value of a new fishery. Many experts 

 believe the harvest of currently-exploited ocean 

 fish can be quadrupled.*" If the present 7.7 

 per cent annual rate of increase of world landings, 

 which has been maintained for more than a 

 decade, continues this level will be reached in 20 

 years, when many more stocks than at present will 

 be exploited at near-maximum yields. 



There is, thus, an urgent need for the develop- 

 ment of methods for fishery resource manage- 

 ment, based on such modern technology as 

 computer simulation models which will take into 

 account, for each stock of fish, not only natural 

 rates of reproduction and growth, food abun- 

 dance, natural mortality, and the increased mor- 

 tality caused by fishing, but also such economic 

 factors as the operational effectiveness of different 

 types of gear and processing and marketing costs. 

 The fashioning of such models will require basic 

 research, since simulation models are no better 

 than our understanding of the interactions be- 

 tween the processes they simulate. 



The use of an approach which fully considers 

 the interactions among the marine organisms, their 

 environment and modern technology, is essential 

 for effective fisheries management. 



Recommendation: 



A continued and expanded effort be directed 

 toward achieving a basic understanding of such 

 key problems as fish population dynamics, the 

 effect of environmental conditions on fish popula- 

 tion, and the dynamics of multi-species systems 

 under predation. 



The Potential Harvest of the Sea, M. B. Schaefer. 

 Transactions, American Fisheries Society, Vol. 94, No. 2, 

 April 1965. 



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