A battery of biomarkers is often used to evaluate the effects of exposure to chemical contaminants and detect responses to environmental stress. Unfortunately, field application of biomarkers is subject to various constraints (e.g., the availability of living material) that can limit data acquisition and prevent the use of multivariate methods during statistical analysis. In these circumstances, a simple method is needed to summarize biomarker responses and simplify their interpretation in biomonitoring programs. The present study used star plots to display results for the panel of biomarkers used for each station and survey. Integrated biomarker response (IBR) was then computed as the star plot area. Star plots using IBR values instead of biomarker data make it possible to visualize between-site and/or between-survey differences for comparison with exposure conditions. This approach was applied to sites in the Baltic Sea and the Seine Estuary, English Channel. In both cases, IBR values were visually compared to polycyclic aromatic hydrocarbons (PAH) or polychlorobiphenyls (PCB) levels measured in mussel or fish tissues. The IBR, as an indicator of environmental stress, appears to be a useful tool for scientists and managers in assessing ecological risk.

A battery of biomarkers is often used to evaluate the effects of exposure to chemical contaminants and detect responses to environmental stress. Unfortunately, field application of biomarkers is subject to various constraints (e.g., the availability of living material) that can limit data acquisition and prevent the use of multivariate methods during statistical analysis. In these circumstances, a simple method is needed to summarize biomarker responses and simplify their interpretation in biomonitoring programs. The present study used star plots to display results for the panel of biomarkers used for each station and survey. Integrated biomarker response (IBR) was then computed as the star plot area. Star plots using IBR values instead of biomarker data make it possible to visualize between-site and/or between-survey differences for comparison with exposure conditions. This approach was applied to sites in the Baltic Sea and the Seine Estuary, English Channel. In both cases, IBR values were visually compared to polycyclic aromatic hydrocarbons (PAH) or polychlorobiphenyls (PCB) levels measured in mussel or fish tissues. The IBR, as an indicator of environmental stress, appears to be a useful tool for scientists and managers in assessing ecological risk.

-In this paper, we present an approach to compare the impact of different management options on the dynamics of a mixed fishery. We used ISIS-Fish, a simulation tool aimed at evaluating the impact of spatial and seasonal management measures on the dynamics of mixed fisheries. The French Nephrops norvegicus (Norway lobster) -Merluccius merluccius (hake) mixed fishery of the Bay of Biscay was chosen as a study case. First, we parameterised the population and exploitation models. We then selected several management measures, including marine protected areas (MPAs) and total allowable catches (TAC), and parameterised fishermen's reaction to each measure. Then, a sensitivity analysis was performed according to a fractional factorial experimental design. Management scenarios were assessed and compared using a statistical simulation design. The sensitivity analysis showed the large influence of some parameters, such as natural mortality, N. norvegicus fecundity, and catchability on both abundance and catches. Given model parameters, an improvement of trawl selectivity and several MPA designs (differing in size, seasonality and location) were found to result in a significant increase in abundance over 10 years, especially for N. norvegicus. This study illustrates the need for a pluri-specific approach to fisheries assessment and management. Key words:Fisheries dynamics / Spatial model / Management measures / Sensitivity analysis / Simulation design Résumé -Évaluation de l'effet de différents scénarios de gestion à l'aide du simulateur « ISIS-Fish » : la pêcherie mixte merlu-langoustine française du golfe de Gascogne. Dans cet article, nous présentons des mé-thodes destinées à comparer l'impact de différentes alternatives de gestion sur la dynamique d'une pêcherie mixte. Pour cela, nous avons utilisé un outil de simulation, « ISIS-Fish », conçu pour évaluer les effets de mesures de gestion spatiales et saisonnières. Nous avons choisi la pêcherie mixte de merlu -langoustine (Merluccius merluccius -Nephrops norvegicus) française du golfe de Gascogne comme exemple d'étude. Dans un premier temps, un paramétrage des modèles de population et d'exploitation a été réalisé. La réaction des pêcheurs face aux mesures de gestion sélectionnées, notamment aux aires marines protégées et aux captures totales admissibles (TAC), a ensuite été programmée. Dans un second temps, une analyse de sensibilité a été réalisée à l'aide d'un plan d'expériences factoriel fractionnaire. Enfin, un second plan de simulation a permis d'évaluer l'effet des différents scénarios de gestion. L'analyse de sensibilité a permis de mettre en évidence l'influence importante de certains paramètres, notamment la mortalité naturelle, la fé-condité de la langoustine et la capturabilité sur les captures et les abondances. Une amélioration de la sélectivité des chaluts et certaines aires marines protégées ont permis d'obtenir une augmentation significative des abondances sur une période de 10 ans, en particulier pour la langoustine. Cette étude a aussi mis en ...

From April 1997 to June 1998, 14 measurements of acetylcholinesterase (AChE) enzymatic activity were performed with the copepod, Tigriopus brevicornis, collected at five stations in the Vilaine River estuary (South Brittany, France). Simultaneously, four chemical analyses of triazines and one analysis of total pesticides in water were undertaken. AChE activity levels in T. brevicornis were compared to the levels measured at a reference site not exposed to effluents from Vilaine River. Results reveal significant differences between AChE activity levels depending on location of stations in the plume of the river with an increasing gradient of activity from the upstream to the downstream stations, thus indicating that neurotoxic contaminants are mainly brought by the river. The average degree of AChE inhibition between the reference site and the most upstream site is 70-80% during spring in 1997 and 1998. In May 1997, live copepods from the different sites were brought back and transferred to clean seawater. After 14 days, recovery of AChE activity was almost total when compared to the control. Moreover, using a linear regression model and the atrazine concentration as marker of the presence of pesticides, low levels of AChE activity were significantly explained by atrazine concentration in water.