Identification of specific malformations of sea urchin larvae for toxicity assessment: Application to marine pisciculture effluents

Standard toxicity screening tests are useful tools in the management of impacted coastal ecosystems. To our knowledge, this is the first time that the sea urchin embryo development test has been used to evaluate the potential impact of effluents from land-based aquaculture farms in coastal areas. The toxicity of effluents from 8 land-based turbot farms was determined by calculating the percentage of abnormal larvae, according to two criteria: (a) standard, considering as normal pyramid-shaped larvae with differentiated components, and (b) skeletal, a new criterion that considers detailed skeletal characteristics. The skeletal criterion appeared to be more sensitive and enabled calculation of effective concentrations EC5, EC10, EC20 and EC50, unlike the classical criterion. Inclusion of the skeleton criterion in the sea urchin embryo development test may be useful for categorizing the relatively low toxicity of discharges from land-based marine fish farms. Further studies are encouraged to establish any causative relationships between pollutants and specific larval deformities.

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► A simple, rapid and cheap method for toxicity evaluation of effluents is presented.
► Mixtures of pollutants may cause specific deformities in sea urchin larva.
► The skeletal criterion increases the sensitivity of sea urchin bioassay.
► Further research may allow detection of mixtures of pollutants.