(herring, cod, plaice, sea perch, etc.), a decrease in the significance 

 of the most important fishing regions of the northern hemisphere, an 

 increase in the number of species, the reserves of which have been 

 reduced by overfishing, a decrease in the success of fishing for most 

 traditional species of fish, and an increase in the importance of fish 

 with lower or unusual food value (anchovy, pollock, Arctic cod, capelin, 

 horse mackerel, etc.). The experience of world fishing during recent 

 decades has confirmed that the intensity of commercial utilization of 

 many traditional species is near its limit, which, in some cases, has 

 already caused overfishing, basic disruption of ecosystems and harmful 

 changes in the genetic structure of populations. The time has come for 

 commercial use of the biologic resources of the lower trophic levels and 

 the most rapid possible development of methods for the control of the 

 biologic processes in the ocean, in order to make the transition from 

 the current hunting stage of fishing to a controlled fish economy with 

 stable fish productivity. 



The need for man to take an active part in the control of the 

 biologic production processes, to change their directions and results in 

 his own interest, is becoming obvious. 



1.2 The Level of the Modern Catch . 



The mean fish productivity of the World Ocean is relatively low: 

 in 1967, with a total seafood catch of 60 million tons (including a 

 correction factor for the catch not accounted for), the productivity, in 

 terms of the entire surface of the World Ocean, was only 167 kg/km 

 (Moiseyev, 1969). In 1970-1975, the total catch (including the same 

 correction factor) approached 70 million tons, averaging 190 kg/km*^. In 

 the most productive regions, the catch amounts to 0.06-0.07% of primary 

 production, which is approximately the level achieved in the highly 

 productive and intensively fished Caspian Sea (0.1%). Special 

 calculations have allowed us to produce an approximate estimate of the 

 potential level of fish production of traditional species in the World 

 Ocean--about 90 million tons (Moiseyev, 1969). Thus, the current catch 

 of fish and large invertebrates is approaching the limit. The world 

 catch of fish and other seafood (excluding whales) is presented below 

 (in millions of tons). 



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