314 MARINE FISHERIES OF NORTH CAROLINA 



perature or circulation of the water. This integrated total of fish is a com- 

 plex network of many equilibria. Many, perhaps all, of these equilibria 

 are not constant but pulsating. The relative abundance of different species 

 rises and falls, one being up while another is down. 



The whole complex system of life at sea has been represented as a 

 pyramid, the base of microscopic Hfe being the most abundant, the suc- 

 cessive consumers being less abundant but larger in (adult) size, the apex 

 being the very large but not numerous sharks, swordfish, tunas, etc. There 

 is reason to believe that removal of fishes high up on the pyramid improves 

 the efficiency of the whole by reducing the average number of transforma- 

 tions of food with their attendant losses, so that exploitation, certainly up 

 to a point, improves the productivity of the region. This fact almost 

 certainly explains in part the failure of the early fears of exhaustion to be 

 realized. The commercial fisheries are mainly concerned with the end 

 product, i.e., the larger animals at or near the top. 



The integration of the fisheries occurs also, as we shall see, in the mostly 

 non-selective methods of capture such as the trawl, seine and pound net, 

 which take an assortment of many kinds of fish that cannot be predeter- 

 mined, and in the marketing of fish, wherein there are few fishes which 

 have no equally acceptable substitute in the market; rather, the totality of 

 most kinds of finfish collectively presses against the total market demand 

 for any kind of fish. For all these reasons, it is unimportant if not impos- 

 sible to isolate one kind of fish and treat it as an independent biological 

 and economic unit. 



The economically important matter is the quantity and value of the 

 total yield of the fisheries, regionally and nationally. Such statistics of 

 world fisheries as are available suggest that while particular species have 

 fluctuated in abundance, the yield of the sea fisheries as a whole or of any 

 considerable region has not only been sustained, but has generally increased 

 with increasing human populations, and there is as yet no sign that they 

 will not continue to do so. No single species so far as we know has ever 

 become extinct, and no regional fishery in the world has ever been exhausted. 

 The fisheries in North America as a whole and in all its regional parts 

 (except some inland waters) have never been exploited to the point of 

 diminishing returns, i.e., where more effort did not produce more fish. This 

 condition probably obtains in all the world fisheries except perhaps locally 

 in a few areas such as the North Sea and the Sea of Japan, and the Canadian- 

 American Great Lakes, in the United States, and perhaps in all the more 

 advanced countries increased production has been accomplished with a de- 

 crease in man-power resulting from more efficient methods. 



Great Multiplicity of Species or Kinds of Fishes. The most comprehensive 

 catalogue of the finfishes in and around the North American continent 



