Bethke, Eckhard (2002) Ist die Steigerung des dauerhaften Fischereiertrages durch Maschengrößenoptimierung möglich? Informationen für die Fischwirtschaft aus der Fischereiforschung, 49(4), pp. 145-153.
The management of a fish aimed at maximising the fishing yield of the managed fish stock. There are models for the yield optimisation since long time. They are used so far mainly to optimise the fishing mortality. Starting point of this paper is a number of fish of an age group of a fish stock. This age group is accompanied over its lifetime. A result of the investigations is that the term growth over-fishing is linked not as frequently assumed exclusive with a too large fishing mortality, but likewise with a mismatch of the mesh opening. The investigations show that the fishing yield increases with the fishing effort on condition that fishing is carried out with an optimised mesh opening. For the calculated example Baltic cod data are used. At present the cod is caught far before reaching the yield optimum. Now the fish is substantially too small when it is caught and did not reach its optimal mass at this time. Therefore the sustainable fishing yield could be increased considerably by the optimasation of the mesh opening. During the conversion from the state of the art to fishing with optimised mesh sizes, however, a loss of profit has to be expected. A further advantage of the mesh enlargement is an increase of the spawning stock size accompanying with it, since the fish is caught at a later age. By the use of substantially larger mesh openings the cod has the opportunity to spawn several times and generate descendants and this will also lead to an increased yield in future. In addition better prices could be obtained at the market by catching larger cod.
|Item Type: ||Article|
|Title: ||Ist die Steigerung des dauerhaften Fischereiertrages durch Maschengrößenoptimierung möglich?|
|Personal Creator/Author: |
|Journal or Publication Title: ||Informationen für die Fischwirtschaft aus der Fischereiforschung|
|Page Range: ||pp. 145-153|
|Contact Email Address: ||email@example.com|
|Issuing Agency: ||Bundesforschungsanstalt für Fischerei|
|Additional Information: ||Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.|
|Uncontrolled Keywords: ||stock management; mathematical model; Beverton-und-Holt-Ertragsmodell; selection parameters|
|Item ID: ||3162|
|Depositing User: ||Horst Bahl|
|Date Deposited: ||17 Apr 2010 14:38|
|Last Modified: ||10 Nov 2012 14:56|
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