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| Bertignac, Michel; De Pontual, Helene. |
| The results of a pilot tagging study on hake (Merluccius merluccius), conducted in the northern part of the Bay of Biscay in 2002, indicate that growth rates for this stock may be currently underestimated because of biased estimates of age. The impact that such a bias may have on the stock dynamics and the trends of the key population parameters, recruitment, spawning-stock biomass (SSB), and mortality are investigated. Assuming new growth parameters, a new age-length key is derived and used to produce and catch-at-age data and abundance indices, which are then used to assess the stock. Bias in estimating age affects the absolute levels of fishing mortality and stock biomass estimates, and also impacts the trend in SSB. However, trends in fishing mortality... |
| Tipo: Text |
Palavras-chave: Tagging; Stock assessment; Simulation; Management; Growth; European hake; Age estimation. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2824.pdf |
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| Vogel, Camille; Kopp, Dorothee; Mehault, Sonia. |
| On January 1st, 2016, the French mixed Nephrops and hake fishery of the Grande Vasière, an area located in the Bay of Biscay, fell under the discard ban implemented as part of the new European Common Fisheries Policy. The fleet records historically high levels of discard despite numerous gear selectivity studies. Together with high discards survival, new technological solutions to minimize catches of undersized individuals could justify local exemptions from the discard ban. Our study focuses on the effects of two selective devices, a square mesh cylinder (SMC) and a grid, on the escapement of undersized individuals and discard reduction. Relative catch probability of the modified gear compared with the traditional gear was modelled using the catch... |
| Tipo: Text |
Palavras-chave: Nephrops; European hake; Discard ban; Gear technology; Catch comparison; Selectivity. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00356/46717/46906.pdf |
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| Mellon-duval, Capucine; De Pontual, Helene; Metral, Luisa; Quemener, Loic. |
| Growth of European hake was estimated from the results of a conventional tagging study in the Gulf of Lions, the first tagging experiment to have been undertaken on the species in Mediterranean waters. In all, 4277 hake 15–40 cm long were tagged and released on the inshore fishing grounds during spring 2006. The overall recapture rate was 6.5% and times-at-liberty ranged from 1 to 717 d. Growth rate in hake varied with size and sex. The estimated growth parameter (von Bertalanffy k) was estimated as double previously published values based on size frequency distribution in the area. Compared with recent growth parameters derived from the tagging experiments in the Bay of Biscay, k was estimated to be slightly lower in the Gulf of Lions. With this faster... |
| Tipo: Text |
Palavras-chave: Age estimation; European hake; Growth; Mediterranean; Tagging. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00000/11134/11532.pdf |
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| Woillez, M; Poulard, Jean-charles; Rivoirard, Jacques; Petitgas, Pierre; Bez, Nicolas. |
| A series of candidate statistical indices is used in an attempt to capture spatial patterns of fish populations from research survey data. To handle diffuse population limits, indices are designed not to depend on arbitrary delineation of the domain. They characterize the location (centre of gravity and spatial patches), the occupation of space (inertia, isotropy, positive area, spreading area, and equivalent area), statistical dispersion (Gini index and coefficient of variation of strictly positive densities), and microstructure. Collocation between different ages and years is summarized by a global index of collocation. Indices are estimated for hake from a bottom-trawl data series in the Bay of Biscay in autumn of 1987-2004. The study provides a... |
| Tipo: Text |
Palavras-chave: Spatial indices; European hake; Bay of Biscay. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2671.pdf |
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| Mahe, Kelig; Amara, R; Bryckaert, T; Kacher, M; Brylinski, J. |
| Analysis of the diet of trawl-caught hake (Merluccius merluccius) from three locations in the Bay of Biscay and the Celtic Sea in autumn 2001 showed that small hake fed almost exclusively on crustaceans (mainly euphausiids), but that there was a significant shift towards a fully piscivorous diet in hake > 23 cm. A change in fish prey was also size-dependent, because smaller hake (< 30 cm) preyed on small pelagic fish (3-12 cm), such as horse mackerel, anchovy, and pilchard, and larger hake on larger demersal prey (12-23 cm), such as blue whiting. There was a significant positive relationship between hake and fish prey length. In terms of fish prey selectivity, hake exhibited particular preference for small pelagic prey (anchovy, pilchard, and... |
| Tipo: Text |
Palavras-chave: Spatial variations; Prey selectivity; Northeast Atlantic; European hake; Diet; Cannibalism. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3849.pdf |
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| Hidalgo, Manuel; Ligas, Alessandro; Maria Bellido, Jose; Bitetto, Isabella; Carbonara, Pierluiggi; Carlucci, Roberto; Guijarro, Beatriz; Jadaud, Angelique; Lembo, Giuseppe; Manfredi, Chiara; Esteban, Antonio; Garofalo, Germana; Ikica, Zdravko; Garcia, Cristina; Gil De Sola, Luis; Kavadas, Stefanos; Maina, Irida; Sion, Letizia; Vittori, Stefania; Vrgoc, Nedo. |
| Most studies on European hake focus on the recruitment process and nursery areas, whereas the information is comparatively limited on the ecology of the juvenile stage (ca. second year of life)-the one most exploited by the Mediterranean trawl fisheries. Using information of the MEDITS programme, we provide a spatial and temporal assessment of the influence of body size and growth on hake survival from recruits (age 0) to juveniles (age 1), along with the impact of surface temperature and chlorophyll variability. At a biogeographic scale, size-dependent survival is supported, with areas with higher mean length of recruits and juveniles yielding higher survival. A similar pattern was observed at interannual level in some western Mediterranean areas, also... |
| Tipo: Text |
Palavras-chave: Juvenile survival; European hake; Mediterranean Sea; Size dependence. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00600/71229/69590.pdf |
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| Pineiro, C; Rey, J; De Pontual, Helene; Goni, R. |
| In the first tagging experiment of European hake (Merluccius merluccius L.) conducted off the NW Iberian Peninsula to study hake growth in the wild we released 527 live tagged individuals. The survival rate after capture and tagging was 58%. Mortality during capture was positively correlated with depth of capture and negatively correlated with hake size. Fifteen months after tagging, seven individuals (1.3%) had been recaptured with times at liberty ranging from 29 to 466 days. We provide the first direct measurements of growth rates of Southern stock European hake in the wild and compare them with rates obtained from tagging experiments in other regions and with rates derived from conventional otolith age reading. The mean somatic growth rate of all... |
| Tipo: Text |
Palavras-chave: Northeast Atlantic; Age estimation; Tag recapture; Growth rates; European hake. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3525.pdf |
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