French marine fish farming deals with several species: sea bass, sea bream, turbot, trout and salmon. In 1992, 20 M fingerlings and 2600 t of fish were produced, for a turnover of 165 MFF: This very technical activity is developing, but still fragile and risky. Environment protection regulation applied to marine fish farming directly inspires from that in force in fresh water, which comes from the industry: i.e. the so-called "classified installation" regulation, concerning activities likely to produce polluting effluents. It does not really adapt to diluted effluents, like fish growing ones, and still less to marine farming; this is true for parameters like biological oxygen demand (BOD) and chemical oxygen demand (COB) and, to a lesser extent, for suspended particulate matter (SPM). Impact studies may be compulsory in the future for farms producing over 20 t/year; this can be a heavy burden, especially for small-medium sized projects. Scientific knowledge related to the impact of marine fish growing on the environment basically comes from the northern countries salmon industry. It does not apply directly to southern Europe species and conditions. Whilst a similar experience is being gained here, a pragmatic regulatory approach is the most convenient. This consists in (1) integrating environment protection needs in the projects since the beginning and all along the lifespan of the farms, with a dialogue between the growers and the administrative authority; (2) appealing to monitoring, which is also interesting for the farming activity itself; (3) allowing the local authorities enough flexibility and supplying them with the necessary scientific support for decision making; for this purpose, marine fish farming regulation has to take into account mainly the relations between effluents and hydrodynamics.