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Huret, Martin; Vandromme, Pieter; Petitgas, Pierre; Pecquerie, Laure. |
Connectivity during early life stages of pelagic fish, defined here by survival probability between spawning and early juvenile habitats, depends on a combination of sufficient food availability and low predator encounter along drift trajectories. For anchovy in the Bay of Biscay, larval transport experiments throughout the spawning season suggest accumulation of early juveniles in the offshore area of the southern Bay, as well as retention over the mid-shelf at mid-latitude. However, late summer-early autumn surveys suggest presence of juveniles only in the former region. From this observation, we set up a bioenergetic individual based model to test for the effect of food availability on survival patterns. The model couples a Lagrangian transport module... |
Tipo: Text |
Palavras-chave: Connectivity; Larval IBM; Bioenergetics; Zooplankton; Bay of Biscay; European anchovy. |
Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00105/21655/19237.pdf |
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Bergeron, Jean-pierre. |
A new biochemical index was used to assess larval fish nutritional condition during a. survey cruise in the Bay of Biscay in early June 1993. This period corresponds to the breeding season of the European anchovy (Engraulis encrasicolus L.). The analysis of samples taken at grid points indicated a clear spatial pattern in nutritional condition, which increased from the middle shelf to the shelf edge. A relatively large fraction of the larval population proved to be in poor condition. Strong winds with speeds of 20-30 knots occurred during 3 d after the first survey and affected the vertical hydrological structure. During a subsequent survey, samples taken at approximately the same locations showed that anchovy larvae in all areas were in very poor... |
Tipo: Text |
Palavras-chave: Windstress; Nutritional condition; Fish larvae; European anchovy; DNA/C; Bay of Biscay. |
Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-449.pdf |
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Petitgas, Pierre; Doray, Mathieu; Masse, Jacques; Grellier, Patrick. |
Fish length frequency histograms from research surveys are of prime importance for identifying habitats of different life stages, as well as for stock assessment. However, no method has thus far been available for mapping these histograms as spatially varying curves. Here, a procedure is applied to map spatially connected curves, and detail is given on how it can be applied to map the length frequency histograms. At each sample location, a fish length frequency histogram is given as a vector of non-independent values. The histogram is first modelled as a polynomial expansion on the basis of orthogonal polynomials. Then, the polynomial coefficients are mapped by co-kriging, after fitting a model of co-regionalization. The length frequency map is finally... |
Tipo: Text |
Palavras-chave: Co-kriging; European anchovy; Fish length; Functional kriging; Habitat; Mapping curves. |
Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00049/16042/13581.pdf |
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