A LINK BETWEEN SCIENCE AND MANAGEMENT 



IN FISHERIES 



D. H. CUSHINGI 



ABSTRACT 



In this paper a link is traced between science and management in that good conservation results from 

 good science and that failure in management may be the result of scientific failure; but management 

 failure is of course not the exclusive province of scientists. The argument is developed from a historical 

 study of practice by fisheries scientists in the International Commissions. 



The central problem of fisheries biology is to esti- 

 mate the catch that can be safely taken from a 

 stock. In Europe the problem was formulated by 

 Petersen (1894) and Garstang (1900), who 

 realized that if catches were too great they might 

 subsequently decrease because the stock had been 

 reduced too much. In the first decade of the present 

 century exploratory voyages were made in the 

 North Sea under the auspices of the International 

 Council for the Exploration of the Sea (ICES). The 

 high variability of the catches "precluded the pos- 

 sibility of any reliable combination of the trawling 

 records" (Garstang, 1904). At the same time, 

 Petersen said that overfishing was not the essen- 

 tial question and that the ICES should study the 

 transplantation of small plaice as a method of 

 conserving the weight of catch. Small plaice were 

 caught in large numbers close to the continental 

 coasts and, in summertime, the discards exceeded 

 the retained catch by a factor of six. Petersen, . 

 Garstang, and Kyle (1907) subsequently wrote 

 that "the plaice can be returned alive to the sea, 

 where they . . . grow so much in size and value that 

 the same fishermen who caught them in the first 

 instance have a good chance of recapturing them 

 when they have a greatly increased value." Dur- 

 ing their adult lives some demersal fish, such as 

 plaice, grow by an order of magnitude or so, and if 

 fished heavily the mean weight of the stock is 

 reduced because the little fish do not have the 

 chance to grow. The problem of growth overfishing 

 as stated by Petersen is to conserve this loss of 

 catch in weight. 



The scientific judgment that catches were too 

 variable led to a second judgment that manage- 

 ment was impossible. The name of the 

 "overfishing" committee in ICES was changed to 



'Ministry of Agriculture, Fisheries and Food, Fisheries 

 Laboratory, Lowestoft, Suffolk, UK. 



Manuscript accepted February 1974. 

 FISHERY BULLETIN: VOL. 72, NO. 4, 1974. 



that "investigating the biology of the Pleuronec- 

 tidae and other trawl-caught fish." The solution 

 recommended for the small plaice problem was to 

 transplant them from the continental coasts to 

 feeding grounds on or around the Dogger Bank. 

 The ICES did not discuss the problem of 

 overfishing again until after the first world war. 

 Management depends on the quality of 

 scientific advice. Good science should lead to good 

 management and failure in management is often 

 due to scientific failure, although failure in man- 

 agement might be due to other causes. It has not 

 been established yet whether the plaice stocks in 

 the southern North Sea needed international 

 management before the first world war, but the 

 lack of management was not based on such a 

 judgment; it was because the scientists could not 

 assess the variability of catches, which was not 

 surprising at that time because statistical tech- 

 niques were not very well developed. This paper 

 traces similar links between science and man- 

 agement in the subsequent history of fisheries sci- 

 ence; the historical information is taken from a 

 study of the development of the fisheries commis- 

 sions in Gushing (1972). 



THE DESCRIPTIVE MODEL 



During the thirties, changes in populations 

 were accounted for in the theory of balance; for 

 example, a decrement in stock is compensated by 

 an increment in recruitment per unit stock, and as 

 fishing mortality increases a relative increase in 

 recruitment is to be expected. Thompson and Bell 

 (1934) and Graham (1935) stated explicitly that 

 recruitment would not be reduced in magnitude 

 by fishing at the stock levels normally exploited; 

 they both worked on flatfish and their conclusion 

 was well fitted to flatfish biology, if not to clupeids 



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