|
|
|
| Registros recuperados: 173 | |
|
|
| Read, Andrew J; Duke University; aread@duke.edu; Brownstein, Carrie R; Duke University; cbrownstein@audubon.org. |
| After decades of overexploitation and severe depletion, Atlantic herring stocks in waters of the northeastern United States have recovered. Fishery managers now consider the herring resource to be underexploited. Nevertheless, some fishery managers and sustainable fishery advocates in New England have expressed concern that the fishery management plan may not adequately consider the importance of herring as prey for marine mammals, seabirds, and piscivorous fish. Several studies suggest that consumption by these predators is significant, yet trophic interactions are not explicitly considered in stock assessment models. Instead, as in most fisheries stock assessments, predation is subsumed within the natural mortality rate, and no empirical estimates of... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Atlantic herring; Ecosystem management; Fisheries management; Gulf of Maine; Marine mammals; Piscivores; Protected species; Single-species approach; Stock assessment; Trophic interactions. |
| Ano: 2003 |
|
| |
|
| |
|
|
| Bertignac, Michel; Auby, Isabelle; Sauriau, Pierre-guy; De Montaudouin, Xavier; Foucard, Julie; Martin, Sophie. |
| As part of a larger project financed by the European Union programme "Community initiative PESCA" on the study of "small scale fisheries" in Aquitaine (France), an estimation of the stock of clams in the Bassin d'Arcachon has been conducted. A two-stage stratified random sampling survey has been designed. Samples have been collected using a Hamon bottom sampler in 237 locations distributed over 24 km2. The clam Tapes philippinarum, which appeared in the basin following a series of aquaculture experiments in the mid eighties, is now the main species accounting for more than 90% of the abundance and the biomass, largely overcoming the European species Tapes decussata. The mean abundance and biomass (26 clams / m2 et l28g / m2) are above those estimated in... |
| Tipo: Text |
Palavras-chave: Palourde; Tapes philippinarum; Tapes decussata; Evaluation stock; Pêche; Pêche à pied; Echantillonnage; Bassin d'Arcachon; Clam; Tapes philippinarum; Tapes decussata; Stock assessment; Fishery; Sampling; Bassin d'Arcachon. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00105/21658/19240.pdf |
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
| Trenkel, Verena. |
| In my work, which is summarised in this paper for obtaining accreditation to supervise research (the HDR), I addressed three areas: i) statistical methods of estimating the density of living resources, ii) mathematical models of population dynamics for estimating the abundance of marine populations and iii) methods for detecting temporal changes in the status of exploited populations. My work has focused on: i) Many studies of the observability of fish by trawling and by video and the development of stochastic models to better assess local fish densities. ii) Development of models without commercial catches, using Bayesian and frequentist approaches; the study of multi-specific relationships and the proposal for a threshold predator-prey model. iii)... |
| Tipo: Text |
Palavras-chave: Statistics; Abundance estimation; Stock assessment; Statistiques; Estimation d'abondance; Evaluation des stocks. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/rapport-1545.pdf |
| |
|
| |
|
| |
|
| |
|
|
| Pons, Maite; Branch, Trevor A.; Melnychuk, Michael C.; Jensen, Olaf P.; Brodziak, Jon; Fromentin, Jean-marc; Harley, Shelton J.; Haynie, Alan C.; Kell, Laurie T.; Maunder, Mark N.; Parma, Ana M.; Restrepo, Victor R.; Sharma, Rishi; Ahrens, Robert; Hilborn, Ray. |
| Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life-history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level.... |
| Tipo: Text |
Palavras-chave: Fisheries management; Marine conservation; Stock assessment; Stock status; Tuna fisheries. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00333/44383/44107.pdf |
| |
|
|
| Caill-milly, Nathalie; Duclercq, Benoit; Morandeau, Gilles. |
| Between 1980 and 1986, some Arcachon oyster farmers took up breeding the Japanese clam on the foreshore (Robert et Deltreil, 1990). This production was short lived. The steep fall in prices due to economic competition from Spain, Portugal, Italy and Tunisia, predator action such as the trigger fish (Popovsky et al., 1999), added to the significant amount of mortality that occurred in the summer and autumn of 1992 that affected two-thirds of the total stock, led to clam farming being abandoned at the end of the 1980s. In the Arcachon basin, the Japanese clam (Ruditapes philippinarum) population, now natural to the area, has found favourable conditions for development and is expanding rapidly there. This species has been supplanting the local species... |
| Tipo: Text |
Palavras-chave: Ruditapes philippinarum; Veneridae; Popluation structure; Biomass; Stock assessment; Arcachon Bassin; Veneridae; Ruditapes Philippinarum; Bivalvia; Mollusca; Structure Population; Biomasse; Abondance; Evaluation Stock. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/2006/rapport-2218.pdf |
| |
|
| |
|
|
| Charuau, Anatole; Chesnier, Véronique; Conan, Gérard; Derennes, Marc; Destanque, Catherine; Guenole, Annie; Isifou, Amadou; Jezequel, Michèle; Miossec, Gilbert; Missaoui, Ichmi; Morizur, Yvon; Rivoalen, Jean-jacques. |
| Introduction : Since 1978, new measures to better manage lobster fisheries were implemented in the Celtic Sea within the context of Community regulations. Meshing, in particular, was set at 60mm, but many owners, in order to maintain sufficient leeway vis-à-vis the regulations and to avoid administrative hassles adopted at the outset fish meshing at 70mm, even 80mm. Certain habits aiming to compensate for the losses due to these increases were established: Adoption of better-performing trawls, increase in the secondary catch and enlargement of the fisheries. At the same time, especially because of strong demand from international bodies, OEM and especially EEC, knowledge about the lobster spread and more reliable assessments were achieved, the main problem... |
| Tipo: Text |
Palavras-chave: Stock assessment; Norway lobster; Celtic sea; Nephrops Norvegicus; Crustacea; Lobster fishery; Mer Celtique; Nephrops Norvegicus; Crustacea; Effort Peche; Sex Ratio; Capture; Relation Taille Poids; Maillage; Chalut; Gestion stock; Peche. |
| Ano: 1982 |
URL: http://archimer.ifremer.fr/doc/1982/rapport-2337.pdf |
| |
|
|
| Mesnil, Benoit. |
| The Catch-Survey Analysis (CSA) method of assessment aims at estimating stock abundance from relative indices by filtering measurement error in the latter through a simple two-stage population dynamics model. The method is not widely used and the associated literature is still limited. The objective of this work is to improve current understanding of the properties of the method, using data generated from a known fully age-structured population. A sensitivity analysis confirms that CSA is capable of providing reliable information about general stock trends. However, absolute estimates are sensitive to the parameter relating survey catchabilities of the two stages, which needs to be estimated externally with methods that warrant further validation. Biased... |
| Tipo: Text |
Palavras-chave: Data limited environments; Collie Sissenwine model; Catch Survey Analysis; Stock assessment. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-439.pdf |
| |
|
|
| Bonhommeau, Sylvain; Fromentin, Jean-marc. |
| This study aims at examining the potential bias in the VPA estimates by simulating a population, catch and CPUEs over 39 years from 1970 to 2008. In the operational model, two levels of noise were added to catch and CPUEs (50 and 100%), three fishing patterns were explored (F=FMSY, F increases linearly from 0.5 FMSY to 2.5 FMSY, F increases linearly from 0.5 FMSY to 2.5 FMSY over the first 34 years and decreases down to FMSY over the last 5 years). We also tested different hypothesis about the impact of the terminal F-ratios, and the natural mortality used in the current VPA as well as the impact of randomly generated CPUE for long-line and trap CPUE. Results show that the VPA is robust to estimate the SSB whatever the noise level in the catch and the... |
| Tipo: Text |
Palavras-chave: Bluefin tuna; Stock assessment; VPA; Management regulations; TAC. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30280/28755.pdf |
| |
|
| |
|
|
| 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 |
| |
| Registros recuperados: 173 | |
|
|
|
