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WOS:000453497600019; International audience; The great scallop, Pecten maximus, presents a strong variability of growth and reproductive patterns along its spatial distribution range. Such differences in life history traits result from complex interactions between organisms and environmental conditions that can be apprehended through the study of energy dynamics. As the determination of accurate food proxy can be a limitation for modeling bioenergetic, recent work by Lavaud et al. (accepted, this issue), based on the DEB theory, provided a new approach consisting of using temperature and growth time series to reconstruct the required assimilated energy to support observed growth. In this study we present an application of this method to growth trajectories of the great scallop P. maximus used to elucidate: (1) life history traits patterns and (2) the choice of food availability proxies. The inverted DEB model was used to reconstruct the functional response (f) for different age classes of P. maximus in 10 locations of its spatial distribution range. We especially explored the patterns of reconstructed f along latitudinal and bathymetric gradients. Average reconstructed f as well as its maximum value were found to increase with latitude. The variability off, although increasing, did not show a significant relationship with the geographical position. Along the bathymetric gradient strong positive relationships were found between the mean f or its variability and depth. Ontogeny had low effect on the reconstructed f. Furthermore, as the inverted DEB model allows the reconstruction of physiological variables and energy fluxes, we explored the potential differences in reserve and maintenance fluxes dynamics from great scallops living in these contrasting environments. For one of the study sites, comparisons of f with field measurements of 11 food indicators (chlorophyll-a from the pelagic/benthic domains, phytoplankton cell counts, etc.) highlighted the complexity of the functional response and the diet of P. maximus. Pelagic or benthic phytoplankton biovolume, diatoms and dinoflagellates counts and chlorophyll-a were found to be the major contributors to the variability of f. Results suggest that although assimilation is best described by a combination of indicators, chlorophyll-a remains a good enough indicator of food availability for great scallops and bivalves in general.

Diel rhythmicity of grazing, swimming, resting andsocial interactions of rohu (Labeorohita)(weight66.5^68.3g) and common carp (Cyprinus carpio)(79.9^82.0g) were observed in1m 2 simulated ponds usingvideoimages. Fishbehaviour was monitored duringafull24-hperiod,startingat08:00hourswitha15-minrecording, whichwas repeated every 3h. Rohu spentmoretimegrazingduringthedaythanatnight.Graz-ingactivity peakedat thebeginningandat the endofthe day. Grazing and resting of rohu were negativelycorrelated.Commoncarpgrazeddayandnight,show-ing no distinctgrazing peak. Considering thegrazingtime of rohu and common carp, a feeding schedulewithtwofeedingtimesat07:30and16:30hoursmightbeappropriateforbetterfoodintakeandconversioninrohu^commoncarppolyculturesystem.Keywords: swimming, grazing, behaviour, rohu,commoncarpIntroductionTogether, rohu Labeo rohita (Hamilton) and commoncarp Cyprinus carpio (L.) contribute 26% (rohu 11%,commoncarp15%)ofthetotalworldfreshwateraqua-culture production outside China (FAO 2005). Nowa-days, rohu^common carp polyculture is being widelypracticed in South Asia. Rohu is a highlyappreciatedconsumption ¢sh, fetching good market prices (Dey,Paraguas, Bhatta, Alam, Weimin, Piumsombun,Koeshandrajana,DungSRahman,Wahab& Verdegem 2007), while common carp is gainingquick popularity as a bottom feeder in South Asiabecause it has a faster growth rate than the nativebottom feeder mrigal Cirrhinus cirrhosus (Bloch)(Milstein,WahabRRahman2006).The eiects of addition of arti¢cial feed and diier-ent densities of common carp on natural food avail-ability, food intake and growth and production inrohu ponds were studied (Rahman, Verdegem,Nagelkerke,Wahab, Milstein & Verreth 2006). It wasobservedthatbotharti¢cialandnaturalfoodsareim-portant for the growth of rohu and common carp.Thepondstudyshowedsynergisticeiectsonnaturalfood availability in rohu^common carp polyculture.The question was raised as to whether the observedsynergism was mainly caused by increased naturalfoodavailabilityorbyachange in feedingbehaviour.Behaviouralstudiesinpondsaredi⁄cultduetohighturbidityand, consequently, low visibility.Therefore,to be able to observe the feeding behaviour, pondtreatments were simulated in aquaria.The eiects ofarti¢cial feed applicationand diierent stocking den-sities of common carp (0, 1 and 2tank

International audience; Susceptibility of two French strains of stable flies Stomoxys calcitrans (L.) to six insecticides was assayed, using an exposure technique (1-hour contact) with treated filter papers. Three replicates per insecticide, per concentration (10 concentrations per insecticide), per fly strain (ENVT, Cabanac) and fly category (blood-engorged - non-blood-engorged) were performed using a total of 14,400 adult flies in this trial. The LD50 and LD90 are higher for the blood-engorged flies than the non-blood-engorged flies for both strains of S. calcitrans. The LD90 (mg/m(2)) of the engorged flies for both strains were respectively: cypermethrin (637.9, 54.9), deltamethrin (264.3, 28.1), fenvalerate (2392.5, 125.1), lambda-cyhalothrin (118.2, 41.3), permethrin (353.7, 88.1), and phoxim (194, 226.8). Phoxim, which has not been used in the ENVT for several years, showed the same susceptibility for both strains. The LD90 values obtained for the Cabanac strain (organic farm) were 1 to 4 times lower than the recommended doses of all five pyrethroids. For the ENVT strain (blood-engorged flies), the LD90 was 7.1 and 22.6 times over the recommended doses of both deltamethrin and fenvalerate respectively, which are commonly used insecticides on this site.

The objective was to take a first step in the development of a process-oriented quality assurance (QA) system for monitoring and safeguarding of fish welfare at a company level. A process-oriented approach is focused on preventing hazards and involves establishment of critical steps in a process that requires careful control. The seven principles of the Hazard Analysis Critical Control Points (HACCP) concept were used as a framework to establish the QA system. HACCP is an internationally agreed approach for management of food safety, which was adapted for the purpose of safeguarding and monitoring the welfare of farmed fish. As the main focus of this QA system is farmed fish welfare assurance at a company level, it was named Fish Welfare Assurance System (FWAS). In this paper we present the initial steps of setting up FWAS for on growing of sea bass (Dicentrarchus labrax), carp (Cyprinus carpio) and European eel (Anguilla anguilla). Four major hazards were selected, which were fish species dependent. Critical Control Points (CCPs) that need to be controlled to minimize or avoid the four hazards are presented. For FWAS, monitoring of CCPs at a farm level is essential. For monitoring purposes, Operational Welfare Indicators (OWIs) are needed to establish whether critical biotic, abiotic, managerial and environmental factors are controlled. For the OWIs we present critical limits/target values. A critical limit is the maximum or minimum value to which a factor must be controlled at a critical control point to prevent, eliminate or reduce a hazard to an acceptable level. For managerial factors target levels are more appropriate than critical limits. Regarding the international trade of farmed fish products, we propose that FWAS needs to be standardized in aquaculture chains. For this standardization a consensus on the concept of fish welfare, methods to assess welfare objectively and knowledge on the needs of farmed fish are required.

Amphipods are an important component of freshwater ecosystems. They are very often used in ecotoxicology, particularly the freshwater amphipod Gammarus pulex. However, there is scarce information on the sensitivity to toxicants of other species within the genus Gammarus. The present study aims to: (1) to compare sensitivities to ivermectin and cadmium between two species of freshwater amphipods (G. pulex and G. fossarum); (2) to compare sensitivities to these toxicants between juveniles and adults within each species; and (3) to assess whether the sensitivity to toxicants of these co-generic species is related with the wideness of their natural distribution area. Eight independent short-term bioassays (96 h) were conducted to assess sensitivity for ivermectin and cadmium for juvenile and adult life stages for each species. The LC50 (mortality) and EC50 (mortality plus immobility) were calculated to 48 and 96 h of continuous exposure. Our results showed that G. pulex was less tolerant to ivermectin than G. fossarum, the reverse being true for cadmium. In general, juveniles of both species were less tolerant to cadmium than adults. In the case of ivermectin, only for G. fossarum EC50 values were different between life stages. These results suggest that the risk assessment of toxicants to freshwater amphipods should include bioassays with the most sensitive species and life stage.