Ecotxicologia

Biondicators. Tools for the impact assessment of aquaculture activities on the marine communities
F. Giménez Casalduero Unidad de Biología Marina, Dpto. Ciencias Ambientales y Recursos Naturales, Universidad de Alicante, Campus de S. Vicente del Raspeig, Apdo 99, 03080 Alicante, Spain

SUMMARY – The use biotic indicators for the assessment of the impact of organic pollution is a very commonmonitoring technique. The present paper presents detailed information about the different types of biological indicators (physiology and immunology bio-indicators, indicators species and biological pollution indices), which can be based on indicator species, on trophic strategies, on the structural heterogeneity, or those incorporating biomass. All these tools can help us to interpret the state of acommunity and the possible changes due to certain environmental pressure. The combined use of different environmental descriptors makes it possible to identify various parameters that are capable of determining the area of impact. Key words: Aquaculture, biotic indicators, impact, marine communities.

RESUME – "Bioindicateurs. Des outils pour l'évaluation de l'impact des activités aquacoles surles communautés marines". L'utilisation des indicateurs biotiques dans l'évaluation de l'impact de la pollution organique est une technique très courante de surveillance. Cet article présente des informations détaillées sur les différents types d'indicateurs biologiques (bioindicateurs physiologiques et immunologiques, espèces indicatrices, et indices de pollution biologique) qui peuvent êtrebasés sur des espèces indicatrices, des stratégies trophiques, l'hétérogénéité structurelle ou ceux incorporant la biomasse. Tous ces outils peuvent nous aider à interpréter l'état de la communauté et les changements possibles provoqués par une certaine pression de l'environnement. L'utilisation conjointe de différents descripteurs de l'environnement permet l'identification de divers paramètrescapables de déterminer la zone de l'impact. Mots-clés : Aquaculture, indicateurs biotiques, impact, communautés marines.

Introduction
At the same time that concerns for the environment have significantly increased during last decades, all food producing sectors, including fisheries and aquaculture, are facing problems of environmental degradation and increasing land and water scarcity. In thiscontext, it has become necessary to explore for the variables which can help us to detect and quantify easily the perturbations caused by mariculture. These variables should give us immediate and effective answers. Approaches may include chemical testing or biological studies. As regards chemical testing this is based in the investigation of changes in chemical components, such as oxygen, dissolvedinorganic nutrients, or organic compounds in benthic fauna that are accumulated (e.g. antibiotics). Another way is to study changes of community structure because the modifications of biota abundance is very sensitive to environmental changes (Satsmadjis, 1985). The biological assessment of water quality is now largely developing because the inclusion of biological indicators in water qualityguidelines and in the assessment of environmental impact. To this respect, it is noted that some regulations and management procedures for coastal aquaculture in northern Europe already contemplate the assessment of impacts from nutrient wastes and chemicals used in finfish aquaculture by modelling and survey techniques, which study the sediment fauna and compare it with general standards (Telfer andBevereidge, this volume).

Indicators
Blandin (1986) defined the term bioindicator as an organism or group of organisms allow to

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characterise the state of an ecosystem based on biochemical, cytological, physiological, ethological or ecological variables. The term "pollution indicator" was defined originally as any measures of corporal fluids, cells, tissues or other biological...