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| Registros recuperados: 25 | |
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| Dube, Benoit; Pawlowski, Lionel; Biseau, Alain. |
| L’étude présentée est une analyse des informations recueillies en 2011 dans le cadre du programme Obsmer en Manche Est (Division CIEM VIId) et mer du Nord (Zone IV), ainsi qu’en mer Celtique sur les chalutiers de fond. Elle complète le précédent document (juin 2011) qui présentait l’analyse des observations des captures 2009-2010 en mer du Nord – Manche Est. Ce document étend l’analyse à la pêcherie française de mer Celtique. |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00110/22172/19828.pdf |
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| Lorance, Pascal; Pawlowski, Lionel; Trenkel, Verena. |
| A database of tallybooks, from skippers' own logbooks, provided by the French industry involved in deep-water fishing to the west of the British Isles was used to standardise blue ling Landings per Unit of Effort (LPUEs). The data covered the years 1992-2008 with more extensive data for the period 2000-2007. For each haul, landings by species, tow duration, depth and location were reported. Compared to EU logbooks, this database is on a haul by haul basis instead of being aggregated by fishing sub-trips combining hauls from the same day, ICES rectangle and gear. Moreover, it includes depth, which is a major factor for catch rates in deepwater fisheries. LPUEs were estimated from Generalised Additive Models (GAMs) with depth, vessel, statistical rectangle... |
| Tipo: Text |
Palavras-chave: Molva dypterygia; Abundance indices; Fishing strategy; Tweedie distribution. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00102/21330/18953.pdf |
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| Véron, Matthieu; Duhamel, Erwan; Bertignac, Michel; Pawlowski, Lionel; Huret, Martin; Baulier, Loic. |
| Age and size at maturation appear as key parameters governing the dynamics of a population as they affect growth rate, fecundity, and survival. The expression of such life history traits is determined by genetic make-up and modulated by environmental factors mainly through phenotypic plasticity. Moreover, fishing, besides decreasing population size and changing demographic composition can alter allelic frequencies through fisheries-induced evolution by selecting for some particular traits. In the Bay of Biscay, a decreasing trend in both sardine body condition and size-at-age has recently been pointed out at the population level. The Probabilistic Maturation Reaction Norm (PMRN) approach was applied to help disentangle phenotypic plasticity and genetic... |
| Tipo: Text |
Palavras-chave: Fisheries-induced evolution; Body condition; Phenotypic plasticity; Maturation; Growth; Sardina pilchardus; Bay of biscay. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00660/77203/78637.pdf |
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| Lorance, Pascal; Pawlowski, Lionel; Trenkel, Verena. |
| Haul-by-haul data derived from skippers' personal logbooks, from the French deep-water fishery to the west of the British Isles, were used to calculate standardized blue ling (Molva dypterygia) landings per unit effort (lpue) for the period 2000-2008. Lpue values were estimated using generalized additive models with depth, vessel, statistical rectangle, area, and year as explanatory variables. Because of their statistical distribution, landings were modelled by a Tweedie distribution, which allows datasets to contain many zeros. To investigate how to track stock trends reliably, lpue values were estimated in five areas for different subsets of the data. The subsets consisted of hauls during the spawning season (when blue ling aggregate), outside the... |
| Tipo: Text |
Palavras-chave: Abundance indices; Fishing strategy; GAM; Molva dypterygia; Tallybook. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00016/12713/9647.pdf |
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| Veron, Matthieu; Lebigre, Christophe; Bertignac, Michel; Doray, Mathieu; Duhamel, Erwan; Huret, Martin; Pawlowski, Lionel. |
| Peu de modèles d'évaluation de stock intègrent une description fine des processus biologiques régissant les populations exploitées par la pêche au sein des écosystèmes. Ce manque est particulièrement regrettable dans le cas des petits pélagiques dont la dynamique est fortement influencée par les conditions environnementales. En effet, la pêche et les fluctuations environnementales et climatiques impactent fortement la dynamique de population de la sardine du golfe de Gascogne. Pour comprendre la dynamique de cette population au sein de l'écosystème et les effets des pêcheries, il est donc nécessaire d'identifier et de caractériser cet ensemble de pressions. Afin d'améliorer la gestion et le suivi de la dynamique de ce stock, le développement d'un modèle... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00410/52133/52842.pdf |
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| Issac, Pierre; Robert, Marianne; Le Bris, Hervé; Rault, Jonathan; Pawlowski, Lionel; Kopp, Dorothee. |
| We used stable isotope ratio and gut content analyses to determine and compare the feeding ecology of two commercially important predator species, Lophius piscatorius and Lophius budegassa in the Celtic sea, where data concerning their trophic ecology remain sparse. This study included two areas and two size-classes, showing that anglerfish in the Celtic sea are mainly piscivorous top predators as observed in other marine waters. However, a substantial part of the diet of the fish in the small size classes consists of benthic macro-invertebrates, mainly Crustaceans. Despite the common knowledge that they are opportunistic predators that display a low degree of prey selectivity, our results suggest that the two species have different trophic niches when... |
| Tipo: Text |
Palavras-chave: Lophius; Gut content; Stable isotopes; Trophic niche; Trophic segregation; Top predator. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50614/51326.pdf |
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| Jardim, Ernesto; Eero, Margit; Silva, Alexandra; Ulrich, Clara; Pawlowski, Lionel; Holmes, Steven J.; Ibaibarriaga, Leire; De Oliveir, Jose A. A. A.; Riveiro, Isabel; Alzorriz, Nekane; Citores, Leire; Scott, Finlay; Uriarte, Andres; Carrera, Pablo; Duhamel, Erwan; Mosqueira, Iago. |
| This paper describes a methodology that combines meta-population theory and stock assessment models to gain insights about spatial heterogeneity of the meta-population in an operational time frame. The methodology was tested with stochastic simulations for different degrees of connectivity between sub-populations and applied to two case studies, North Sea cod (Gadus morua) and Northeast Atlantic sardine (Sardina pilchardus). Considering that the biological components of a population can be partitioned into discrete spatial units, we extended this idea into a property of additivity of sub-population abundances. If the additivity results hold true for putative sub-populations, then assessment results based on sub-populations will provide information to... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00422/53385/54236.pdf |
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| Kopp, Dorothee; Robert, Marianne; Pawlowski, Lionel. |
| In marine ecosystems, the study of trophic relationships has extensively benefited from the development of stable isotope analyses (SIA) as dietary tracers. SIA are particularly useful in elucidating the structure of deep sea food webs given the constraints involved in obtaining gut-content data from deep trawling. We used carbon and nitrogen stable isotope analyses and Stable Isotope Bayesian Ellipses in R (SIBER) and Stable Isotope Analysis in R (SIAR) routines, to determine the trophic ecology of five deep-sea fishes from the upper continental slope of the Celtic Sea. SIA made it possible to deduce some general tendencies in food-web structure and species trophic interactions and confirmed diet determined by gut-content analysis for the same species, in... |
| Tipo: Text |
Palavras-chave: Competition; Feeding habits; Mixing models; Stable isotope. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00410/52138/52940.pdf |
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| Reid, David G; Calderwood, Julia; Afonso, Pedro; Bourdaud, Pierre; Fauconnet, Laurence; Gonzalez-irusta, José Manuel; Mortensen, Lars O; Ordines, Francesc; Lehuta, Sigrid; Pawlowski, Lionel; Plet-hansen, Kristian S; Radford, Zachary; Robert, Marianne; Rochet, Marie-joelle; Rueda, Lucia; Ulrich, Clara; Vermard, Youen. |
| Under the Landing Obligation (LO) fishers will need to reduce or land fish that were previously discarded. In this chapter we look at how they might be able to do that by summarising a number of studies conducted in various European regions. We start by describing a series of “challenge” trials where fishers tried to reduce their discards by whatever (legal) means they thought best. In some cases, they were able to reduce unwanted catches, in others they were less successful. We also interviewed fishers not involved in the trials to ask them what they thought they could do. We explore their approaches which generally fell into three categories: more selective gear; tactical and strategic changes; and management changes. Scientific data (surveys, landings,... |
| Tipo: Text |
Palavras-chave: Challenge trials; Decision support tools; Discard avoidance; Fine scale mapping; Fish distribution; Fishers; Fishing strategies; Hot-spot maps. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00473/58428/61004.pdf |
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| Silva, Alexandra; Moreno, Ana; Riveiro, Isabel; Santos, Begoña; Pita, Cristina; Garcia Rodrigues, Joao; Villasante, Sebastian; Pawlowski, Lionel; Duhamel, Erwan. |
| This study describes fisheries, stock status, ICES advice and management measures for the Northern and Southern sardine stocks in EU Atlantic waters. Information on sardine biology and ecology is provided for a better understanding of stock development. Social and economic dimensions are addressed for sardine fisheries in France, Spain and Portugal. The study provides recommendations to improve knowledge on the species and indicates management measures which might be considered for the sustainability of the fisheries. |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00300/41109/40280.pdf |
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| Marchal, Paul; De Oliveira, Jose A. A.; Lorance, Pascal; Baulier, Loic; Pawlowski, Lionel. |
| We develop a spatially and seasonally explicit bioeconomic model with three fleet dynamics processes built in endogenously. The model has been applied to the large French trawlers harvesting a medium-depth demersal stock, North Sea saithe (i.e., pollock, Pollachius virens), and a mix of deepwater species over a 10-year period (1999-2008), and the predictions have been contrasted with observations. The best overall fit was achieved where effort allocation was determined to be 80% by traditions and 20% by economic opportunism and where harvest efficiency increased by 8% a year. With this fleet dynamics parameterization, annual trends in fishing effort and profit were well reproduced by the model over the whole time period. Time series of the observed fishing... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00151/26227/24329.pdf |
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| Silva, Alexandra; Garrido, Susana; Ibaibarriaga, Leire; Pawlowski, Lionel; Riveiro, Isabel; Marques, Vitor; Ramos, Fernando; Duhamel, Erwan; Iglesias, Magdalena; Bryere, Philippe; Mangin, Antoine; Citores, Leire; Carrera, Pablo; Uriarte, Andres. |
| This work investigated adult-mediated connectivity and spatial population structure of sardine in the European Atlantic waters. The spatial and temporal progress of cohorts was modelled using abundance-at-age survey data by area in the period 2000 to 2016, covering the region from the northern Bay of Biscay to the eastern Gulf of Cadiz. A novel methodology was used to calculate indices of cohort movement between areas. Movement was relatively low between three large regions, the Bay of Biscay, the northern Spanish and Portuguese waters and the Gulf of Cadiz, each hosting a recruitment hotspot. On the other hand, one half of the sardines recruited in North Portugal and a quarter of those recruited in Southwest Portugal moved to northern Spanish waters and... |
| Tipo: Text |
Palavras-chave: Metapopulation; Source-sink dynamics; Adult-mediated connectivity; Cohort dispersal; Small pelagic fishes; Stock identity; Fisheries management. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00465/57661/59856.pdf |
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| Registros recuperados: 25 | |
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