Arrest and Delay in Embryonic Development in Sea Urchin Populations of the Bay of Brest (Brittany, France): Link with Environmental Factors

The deficiencies observed in the larval development of several populations of the sea urchin Sphaerechinus granularis from the Bay of Brest were used to evaluate the quality of seawater. The comparison of ecotoxicological indices reveal that there are significant differences between the reference populations and the populations located in the centre and northern areas of the Bay, the sea urchins living at the mouth of the river Aulne having the highest level of blockage and delay in embryonic development. Analysis of heavy metals present within the sea urchin gonads reveals concentrations that are 2– 5 times higher than those observed in the other populations of the Bay. A discussion is carried out based on these results and on different environmental factors. The developmental abnormalities observed at this site could be linked to dumping of heavy metals from pyrotechnical waste but also to dumping of pesticides from agricultural sources, and TBT plus PAHs concentrations from urban and port activities.