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| Fromentin, Jean-marc; Kell, Laurence T. |
| An integrative simulation framework was built to evaluate the consequences of variability attributable to changes in carrying capacity or the stock’s migration pattern of Atlantic bluefin tuna on the ICCAT stock assessment and management procedures. We also evaluated the performances of stock assessment methods with respect to their ability to provide good estimates of MSY, FMSY and BMSY and tested the robustness of the current ICCAT management strategy to uncertainty about the true dynamics and historical exploitation levels. The results clearly indicate that the VPA performances were seriously impaired if the long-term variations in catches are due to changes in migration/availability. There is further considerable confounding between the underlying... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Stock assessment; VPA; Biological reference points; MSY; Management strategy; Simulation model. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00192/30295/28786.pdf |
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| Cervino, Santiago; Dominguez-petit, Rosario; Jardim, Ernesto; Mehault, Sonia; Pineiro, Carmen; Saborido-rey, Fran. |
| Spawning stock biomass (SSB) is one of the most common measures of stock status. However recent research on reproductive potential has shown that alternative variables may be an improvement over SSB. In the case of European hake (Merluccius merluccius), it is known that large individuals produce more eggs by unit of body weight, and their quality is better than those of small individuals. Under these circumstances, application of reproductive potential may be pertinent in the implementation of the Johannesburg agreement, since it is not only the spawning biomass but also its age or length structure that defines stock productivity and its ability to achieve maximum sustainable yield (MSY). In this contribution we used an age-length structured population... |
| Tipo: Text |
Palavras-chave: Egg production; Biological reference points; Steepness; Length based models; Hake. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00161/27254/25487.pdf |
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| Rochet, Marie-joelle. |
| Density dependence means that exploited fish populations exhibit earlier maturity, a faster growth rate, increased fecundity and reduced egg size. Here, the consequences of these effects on population dynamics, the estimation of spawning biomass per recruit and associated biological reference points are examined by a simulation model. The model is a self-regenerating model in which the population parameters (age at maturity, growth, fecundity, egg size) vary according to three classes of population abundance. Early life stages are characterized by a size-dependent growth and mortality model. It is concluded that spawning per recruit is an ambiguous concept because, if density dependence occurs in the adult population, the spawning biomass of a cohort is... |
| Tipo: Text |
Palavras-chave: Teleost fishes; Population dynamics; Life history; Density dependence; Biological reference points. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-485.pdf |
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| Heino, Mikko; Baulier, Loic; Boukal, David S.; Ernande, Bruno; Johnston, Fiona D.; Mollet, Fabian M.; Pardoe, Heidi; Therkildsen, Nina O.; Uusi-heikkila, Silva; Vainikka, Anssi; Arlinghaus, Robert; Dankel, Dorothy J.; Dunlop, Erin S.; Eikeset, Anne Maria; Enberg, Katja; Engelhard, Georg; Jorgensen, Christian; Laugen, Ane; Matsumura, Shuichi; Nussle, Sebastien; Urbach, Davnah; Whitlock, Rebecca; Rijnsdorp, Adriaan D.; Dieckmann, Ulf. |
| Biological reference points are important tools for fisheries management. Reference points are not static, butmay change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to "shifting" reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in "true" reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in... |
| Tipo: Text |
Palavras-chave: Biological reference points; Fisheries-induced evolution; Fisheries management; Population dynamics; Precautionary approach; Uncertainty. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00151/26228/24302.pdf |
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