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| Jean, Frederic; Hilly, C. |
| Macroepifauna of mixed sediments was quantitatively studied at three stations in the Bay of Brest. Samples were collected with the quantitative video dredge Aquareve II. Sampling performance varied from 6.1 to 55.6 m2 according to the mesh diameter of the net (10, 40, and 70 mm) and the quality and quantity of the hard structures lying on the bottom. The efficiency of the different sampling options is tested. The ecological analysis shows differences between epifaunal assemblages, which are mainly explained by the characteristics of the ruggedness in each station. Ruggedness is defined in terms of quality and quantity of hard structures (pebbles, gravel, shells, coraline algae and macroalgae) lying on the sediment surface. Hard substrates act as... |
| Tipo: Text |
Palavras-chave: EPIBENTHOS; SAMPLING METHOD; QUANTITATIVE DISTRIBUTION; MICROHABITATS; TROPHIC WEB. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00098/20894/18508.pdf |
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| Aguirre-velarde, Arturo; Thouzeau, Gerard; Jean, Frederic; Mendo, Jaime; Cueto-vega, Rosa; Kawazo-delgado, Midori; Vásquez-spencer, Jazmín; Herrera-sanchez, Diego; Vega-espinoza, Alex; Flye-sainte-marie, Jonathan. |
| The response of Argopecten purpuratus (Peruvian scallop) to environmental conditions was studied in the upwelling-influenced Bay of Paracas (Peru). Scallops growth and reproduction were monitored weekly over a 7-month period under two conditions (culture depths): on the bottom and 2 m above (suspended culture). At the same time, a high-frequency environmental monitoring was realized at the aforementioned depths. The results indicate that environmental conditions in the Bay are highly variable, especially during the summer: temperature fluctuations up to 8∘C were recorded in less than one day while oxic conditions ranged from oversaturation to anoxia. Milky-turquoise waters discoloration events (sulphide presence suspected) were simultaneously observed... |
| Tipo: Text |
Palavras-chave: Argopecten purpuratus; High frequency monitoring; Coastal upwelling; Hypoxic/anoxic conditions; Growth; Reproduction; Aquaculture; Milky-turquoise water/aguas Blancas. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00504/61547/65430.pdf |
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| Foucher, Eric; Blanchard, Michel; Cugier, Philippe; Desroy, Nicolas; Dreanno, Catherine; Fauchot, Juliette; Fifas, Spyros; Guyader, Olivier; Jean, Frederic; Le Gallic, Bertrand; Riou, Philippe; Schapira, Mathilde; Thiebaut, Eric. |
| The King scallop Pecten maximus constitutes the first landed species in terms of tonnage and the second or third one in terms of value for the French fisheries. More than 90% of these landings come from the English Channel indicating that its exploitation is essential to local fleets. The COMANCHE project (Ecosystem Interactions and anthropogenic impacts on King scallops populations in the English Channel) proposed to improve the knowledge of the scallop within the Channel, through an ecosystem-based approach for fisheries, appealing to a wide range of scientific disciplines (physics, chemistry, genetics, ecology, geostatistics, modeling, economics ....). Researches on the spatial location of scallop beds, connectivity by larval dispersal between beds,... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00251/36236/34797.pdf |
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| Ragueneau, Olivier; Raimonet, Melanie; Maze, Camille; Coston-guarini, Jennifer; Chauvaud, Laurent; Danto, Anatole; Grall, Jacques; Jean, Frederic; Paulet, Yves-marie; Thouzeau, Gerard. |
| In this contribution, the study of the Bay of Brest ecosystem changes over the past 50 years is used to explore the construction of interdisciplinary knowledge and raise key questions that now need to be tackled at the science-policy-communities interface. The Bay of Brest is subject to a combination of several aspects of global change, including excessive nutrient inputs from watersheds and the proliferation of invasive species. These perturbations strongly interact, affecting positively or negatively the ecosystem functioning, with important impacts on human activities. We first relate a cascade of events over these five decades, linking farming activities, nitrogen, and silicon biogeochemical cycles, hydrodynamics of the Bay, the proliferation of an... |
| Tipo: Text |
Palavras-chave: Sustainability; Land-ocean continuum; Bay of Brest; Interdisciplinarity; Science-policy-community interface. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00616/72792/72272.pdf |
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| Mcfarland, Katherine; Soudant, Philippe; Jean, Frederic; Volety, Aswani K.. |
| Understanding the population dynamics of invasive species, such as the green mussel Perna viridis (Linnaeus, 1758), can aid in explaining the success of newly introduced populations and help predict the potential for spread. During a two-year field study of established populations in the invaded region of southwest Florida, year round gametogenesis and continuous spawning capabilities were observed through histological analysis of mussels collected monthly. This was supported by overall stable energetic reserves as measured through proximal biochemical composition (protein, glycogen and lipid content). However, egg outputs in the summer (6.4 x 10(6) +/- 2.6 x 10(6) eggs / female) were significantly higher than egg outputs of winter-spawned mussels (7.7 x... |
| Tipo: Text |
Palavras-chave: Gametogenesis; Protein; Glycogen; Lipid; Induced spawning. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00616/72842/72974.pdf |
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| Cueto‐vega, Rosa; Flye‐sainte‐marie, Jonathan; Aguirre‐velarde, Arturo; Jean, Frederic; Gil‐kodaka, Patricia; Thouzeau, Gerard. |
| During recent years, mass mortalities of cultured scallops became more frequent in Peruvian bays. One of the main drivers related to these mortalities was hypoxic events. This study was designed to understand the hypoxia phenomenon in these bays and to assess how the Peruvian scallop, Argopecten purpuratus, can cope with reduced oxygen levels in seawater based on individual size. First, we analyzed the relationships between dissolved oxygen saturation and other environmental parameters (the Coastal El Niño Index, temperature, salinity and pH) in bottom seawater, the frequency and intensity of hypoxic events in two main culture areas (Sechura and Paracas Bays), and their relationship with scallop mass mortalities. Then, we performed experiments with two... |
| Tipo: Text |
Palavras-chave: Argopecten purpuratus; Lt50; Mass mortality; Severe hypoxia; Size effect. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00692/80410/83521.pdf |
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