| Abstract: |
| Empirical evidence and biological characteristics of pelagic fish suggest that, in contrast to traditional fishery models, marginal catch of pelagic species does not react in linear way to changes in stock level. In this presentation, we allow non-linearity in the harvesting function of Cobb-Douglas type and propose a variant of single-stock harvesting model with invariable ``catch-to-effort`` parameter and variable ``catch-to-stock`` parameter that measures the sensitivity of an additional catch yield to marginal changes in the fish stock level. Using the optimal control modeling framework, we provide an explicit form of sustainable fishing policy in terms of stationary stock that continuously depends upon the ``catch-to-stock`` parameter and then focus on analysis of the equilibrium responses to changes in this parameter induced by external perturbations. |
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