PRODUCTION FUNCTIONS AND BIOECONOMIC 

 MODELS: RESEARCH IMPLICATIONS 



Against the broad background of these four 

 introductory papers we can proceed to some of 

 the more specific research which will constitute 

 the principal inputs into the broader manage- 

 ment process. The first of these papers relates 

 the results of an extensive effort by Carlson to 

 specify production functions for the North 

 Atlantic groundfish and tropical tuna fisheries. 

 In each case the research is designed to identify 

 the most significant determinants of vessel 

 productivity, with some of the investigation 

 devoted to the question of a proper measure 

 of productivity. 



Using existing data series on the area and 

 time patterns of fishing activity, landings 

 statistics on species, quantity and value, and 

 other sources of data on vessel characteristics, 

 specific effort combinations are related to produc- 

 tivity. The "best" measure of productivity was 

 found to be value in groundfish and a weighted 

 combination of species landed in tuna. 



This research output has many possible uses, 

 among these being the suggestion of the 

 optimum input package to maximize output 

 and the development of a fishing power index 

 which could be used to measure effort, a critical 

 input into those types of management plans that 

 require the administrator to develop seasonal 

 or sharing arrangements based on the fishing 

 capabilities of the fleet. This is the case for the 

 Inter-American Tropical Tuna Commission. 

 Here a technique of measuring fishing power 

 has evolved which is somewhat different from 

 the Carlson approach. Future investigations 

 will determine the advisability of each approach. 

 Indeed, if differences and difficulties cannot be 

 resolved, this may have some effect on the choice 

 between management plans which require this 

 type of calculation and types which do not. 



The paper by Segura relates part of his broad 

 investigation into the world supply and demand 

 for fish meal. His efforts for this paper have 

 concentrated on a measure of fishing power in 

 the Peruvian anchoveta fieet for the purpose of 

 determining the optimum harvest level. His 

 focus is upon the role of technological change 



as this relates to time series calculations of 

 effort indices. 



In his paper, Segura points out the differing 

 results which will be forthcoming if you use 

 the most recent years' measure of yield-effort, 

 the index of vessel productivity, to calculate 

 changing pressures on the resource, the response 

 of the resource to that pressure, and use these 

 relationships to determine an optimum catch 

 quota for the coming year. He compares these 

 results to calculations now used where these 

 interrelationships are all derived based upon 

 some earlier base year. The results are sub- 

 stantially different, resulting in a suggested 

 catch of 16.2 million ton trips derived via the 

 existing method. 



The work done by Segura relates closely to 

 that of Carlson in that a method of cross- 

 sectional analysis of recent years' data is being 

 developed which obviates the need to use 

 standard vessels from some base period, supple- 

 mented by ad hoc measures of technological 

 change. These considerations are in addition to 

 the question of diminishing returns as intro- 

 duced by the Carlson-Waugh-Bell function. 



The research reported by Rich is an extension 

 of a generalized model to be applied to the 

 Pacific halibut fishery. The purpose is to evaluate 

 possible losses which may have resulted in the 

 fishery from the use of MSY as a regulation goal. 



Consistent with the Carlson-Waugh-Bell 

 exposition, the function developed incorporates 

 short run diminishing returns. When combined 

 with a fish growth function it is possible to 

 measure the long run externalities associated 

 with this alternative specification of the yield- 

 effort function. 



This approach is the antithesis of that sug- 

 gested by Pontecorvo in that it is explicitly 

 structured upon the classic assumptions of full 

 employment and complete labor mobility, both 

 in the short run and the long run. Political 

 and social questions are definitely excluded 

 and would have to be appended on an ad hoc 

 basis to determine if there was any cause for 

 modifying the constrained results. The work 



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