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| Cormon, Xochitl. |
| North Sea saithe (Pollachius virens) has high economic value for European fisheries. In recent years, North Sea saithe abundance has decreased, while abundance of hake (Merluccius merluccius), which was rarely fished in the North Sea, has increased dramatically in the area. This work investigates the nature of the ecological interactions between saithe and hake in the North Sea, in order to understand if recent hake emergence in this area could explain, at least partially, the recent decline of the saithe stock. The results obtained during this research suggested competitive interactions between saithe and hake predators in the area. In addition, this investigation revealed potential negative effects of hake on the resident saithe stock. Therefore, hake... |
| Tipo: Text |
Palavras-chave: Compétition; Lieu noir; Merlu; Simple réseau trophique; Émergence d’un prédateur; Mer du nord; Exploitative competition; Saithe; Hake; Simple foodweb; Up-coming predator; North sea. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00345/45638/45268.pdf |
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| Payne, Mark R.; Barange, Manuel; Cheung, William W. L.; Mackenzie, Brian R.; Batchelder, Harold P.; Cormon, Xochitl; Eddy, Tyler D.; Fernandes, Jose A.; Hollowed, Anne B.; Jones, Miranda C.; Link, Jason S.; Neubauer, Philipp; Ortiz, Ivonne; Queirós, Ana M.; Paula, José Ricardo. |
| Projections of the impacts of climate change on marine ecosystems are a key prerequisite for the planning of adaptation strategies, yet they are inevitably associated with uncertainty. Identifying, quantifying, and communicating this uncertainty is key to both evaluating the risk associated with a projection and building confidence in its robustness. We review how uncertainties in such projections are handled in marine science. We employ an approach developed in climate modelling by breaking uncertainty down into (i) structural (model) uncertainty, (ii) initialization and internal variability uncertainty, (iii) parametric uncertainty, and (iv) scenario uncertainty. For each uncertainty type, we then examine the current state-of-the-art in assessing and... |
| Tipo: Text |
Palavras-chave: Climate change; Initialization uncertainty; Parametric uncertainty; Projections; Scenario uncertainty; Structural uncertainty; Uncertainty.. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00301/41220/40392.pdf |
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| Cormon, Xochitl; Ernande, Bruno; Kempf, Alexander; Vermard, Youen; Marchal, Paul. |
| North Sea saithe Pollachius virens, a major top predator in the area, supports the fishery economy of several European countries. However, recent stock assessments suggested a decrease in spawning stock biomass along with a decline in saithe mean weight-at-ages. In this context, we investigated North Sea saithe growth characteristics at the population level. First, saithe annual weight increments and age-length relationships were studied. Modelling of saithe age-length relationships was carried out using (1) the traditional von Bertalanffy growth function model, (2) the Verhulst logistic model and (3) an empirical linear model. Second, the effects of environmental factors on saithe growth were investigated. Explanatory environmental factors included food... |
| Tipo: Text |
Palavras-chave: Bottom-up processes; Von Bertalanffy growth function; Logistic growth; Norway pout; Prey availability effects; Density-dependence; Predator-prey interactions; Resource limitation; Competition. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00314/42499/41875.pdf |
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| Cormon, Xochitl; Kempf, Alexander; Vermard, Youen; Vinther, Morten; Marchal, Paul. |
| During the last 15 years, northern European hake (Merluccius merluccius) has increased in abundance, and its spatial distribution has expanded in the North Sea region in correlation with temperature. In a context of global warming, this spatial shift could impact local trophic interactions: direct impacts may affect forage fish through modified predator–prey interactions, and indirect impacts may materialize through competition with other resident predators. For instance, North Sea saithe (Pollachius virens) spatial overlap with hake has increased while saithe spawning-stock biomass has decreased recently notwithstanding a sustainable exploitation. In this context, we investigated the range of potential impacts resulting from most recent hake emergence in... |
| Tipo: Text |
Palavras-chave: Hake; Interspecific competition; Maximum sustainable yield; Multispecies stock assessment; Norway pout; Predator-prey interactions; Saithe; Simple foodweb; SMS. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00327/43794/45917.pdf |
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| Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Cormon, Xochitl; Marchal, Paul. |
| The objective of this study is to analyse at fine scale the annual, seasonal and spatial distributions of several species in the Eastern English Channel (EEC). On the one hand, data obtained from scientific surveys are not available all year through, but are considered to provide consistent yearly and spatially resolved abundance indices. On the other hand, on-board commercial data do cover the whole year, but generally provide a biased perception of stock abundance. The combination of scientific and commercial catches per unit of effort (CPUEs), standardized using a delta-generalized linear model, allowed to infer spatial and monthly dynamics of fish distributions in the EEC, which could be compared with previous knowledge on their life cycles.... |
| Tipo: Text |
Palavras-chave: Commercial data; Eastern English Channel; Seasonality; Spatial distribution; Survey data. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49805/50385.pdf |
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