Changes between Version 2 and Version 3 of EwEugPredictingSpatialFishingPatterns


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Timestamp:
2010-11-22 22:35:19 (9 years ago)
Author:
shermanl
Comment:

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  • EwEugPredictingSpatialFishingPatterns

    v2 v3  
    11== 4.5 Predicting spatial fishing patterns == 
    22 
    3 EwE works with multiple fishing fleets, with fishing mortality rates (''F'') initially distributed between fleets based on the distribution in the underlying Ecopath base model. In Ecospace the ''F''’s are distributed using a simple ‘gravity model’ where the proportion of the total effort allocated to each cell is assumed proportional to the sum over groups of the product of the biomass, the catchability, and the profitability of fishing the target groups (Caddy, 1975; Hilborn and Walters, 1987). This profitability of fishing includes factors such as the cell-specific cost of fishing. 
     3EwE works with multiple fishing fleets, with fishing mortality rates (''F'') initially distributed between fleets based on the distribution in the underlying Ecopath base model. In Ecospace the ''F'''s are distributed using a simple 'gravity model' where the proportion of the total effort allocated to each cell is assumed proportional to the sum over groups of the product of the biomass, the catchability, and the profitability of fishing the target groups (Caddy, 1975; Hilborn and Walters, 1987). This profitability of fishing includes factors such as the cell-specific cost of fishing. 
    44 
    55Assuming that there are ''N'' cells representing water areas, each fleet k can cause a total fishing mortality rate ''N · F,,k,,''. For each step in the simulation this rate is distributed among cells, c, in proportion to the weights ''G,,kc,,'' based on: