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| Registros recuperados: 173 | |
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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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| Hamon, Pierre-yves; Tournier, Henri. |
| Since 1980, the IFREMER research laboratory "Resources Aquacoles", Sete (France), follows during the summer period, the evolution of the commercial stocks of molluscs (mussels and oysters) reared in Thau Lagoon. The data for this estimation are collected, on one hand, by surface observations and, on the other hand, by diving observations. During the years 1980 to 1984, the authors noticed an increase of oyster biomass, during the same period the mussel biomass decreased. The different simulations used to know the total filtration and the biodeposit, have shown that the impact of the increase of the total biomass is not so important as it could be feared. |
| Tipo: Text |
Palavras-chave: Bivalvia; Marine mollusks; Stock assessment; Population density; Biomass. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/publication-1787.pdf |
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| Hammond, T; Trenkel, Verena. |
| Landings statistics can be lower than true catches because many fish are discarded or landed illegally. Since many discards do not survive, treating landings as true catches can lead to biased stock assessments. This paper proposes treating catch as censored by bounding it below by the landings, L, and above by cL (for scalar c > 1), We demonstrate the approach with a simulation study, using a Schaefer surplus production model. Parameters were estimated in a Bayesian framework with BUGS software using two sets of priors. Both the traditional true-catch method and a survey-and-effort method (which was landings free) performed worse on average than the censored approach, as measured by the Bayes risk associated with estimates of maximum sustainable yield... |
| Tipo: Text |
Palavras-chave: Stock assessment; Misreporting; Discarding; Censored data. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-641.pdf |
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| Mellon, Capucine. |
| Cod (Gadus morhua, L.), whiting (Merlangius merlangus, L.), saithe (Pollachius virens, L.), haddock (Melanogrammus aeglefinus, L.), sole (Solea vulgaris, L.) and plaice (Pleuronectes platessa, L.) make up the main demersal stocks under quota which concern the French fishery in North Sea and Eastern English Channel. The diagnosis on the state of stocks are set up at the International Council for the Exploration of the Sea (ICES). Recommendations which result from the analyses are proposed to the European Union. Most of the stocks are close or outside their safe biological limits. Several reasons account for that such as the high fishing mortality rates and mixed fisheries on species with diverse biological characteristics. Consequently, more and more young... |
| Tipo: Text |
Palavras-chave: Demersal stocks; ANE; North Sea; Eastern English Channel; Mixed fishery; Biological characteristics; Landings; Stock assessment. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00447/55905/57907.pdf |
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| Registros recuperados: 173 | |
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