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| Fromentin, Jean-marc. |
| The aim of this study is to investigate the implications of different stock-recruitment assumptions when examining the potential of Dubrovnik’s bluefin tuna recovery plan. To do so, some Beverton and Holt relationships displaying contrasting steepness of 0.99, 0.90, 0.75 and 0.50 were applied within a simulation model. In addition to these four stock-recruitment scenarios, parental effects and stochastic variations were also considered. The main conclusion is that our ability to evaluate the consequences of the Dubrovnik agreement (as any set of management measures) relies on our capacity to predict future recruitment levels in an accurate way. Assuming a Beverton and Holt relationship with different steepness, with or without parental effects and with or... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Management regulations; Stock-recruitment; Parental effects; Stock rebuilding; Simulation model. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00192/30296/28784.pdf |
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| Mesnil, Benoit; Rochet, Marie-joelle. |
| With political commitment to restore stocks to levels where they can produce maximum sustainable yield (MSY), fisheries managers request evaluations of management plans that include options for an FMSY policy. The procedure to estimate FMSY with dynamic-pool, stock assessment models is well established for common stock-recruitment relationships (S-RR). In this paper, we extend this capacity to another S-RR, a piecewise function known as the hockey stick, which is frequently assumed when the data do not support more elaborate functions. However, the hockey stick is not continuous, which makes it problematic for this application, where differentiable functions are required. The bent-hyperbola model proves to be an adequate continuous equivalent to the hockey... |
| Tipo: Text |
Palavras-chave: Bent hyperbola; F-MSY; Hockey stick; MSY; Stock-recruitment. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00016/12735/9667.pdf |
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