Laboratory versus wild populations: the importance of population origin in aquatic ecotoxicology.

The origin of the populations used in ecotoxicological bioassays (from nature (wild populations) or from cultures (laboratory populations)) could have a key influence on the sensitivity of the tested species to different toxicants. However, the available information on this subject is scarce. To assess the likely influence of the population origin (wild vs. laboratory) of species-genus on the toxicant tolerance, we performed a quantitative review of the ECOTOX database, from which we collected the effective concentrations for a wide range of compounds (metals and organics), endpoints, and exposure times. We found a general trend of lower sensitivity of wild populations to toxicants than laboratory populations, although sensitivity was dependent on species and toxicant groups. This suggests that the results of bioassays with laboratory populations may overestimate the toxicity of most of the compounds. Our study highlights the relevance of the origin of the populations in the determination of the sensitivity of species to toxicants. This study also warns about the biases in the species and toxicants used in ecotoxicology, which may lead to an underrepresentation of the biodiversity and the toxicological context of aquatic ecosystems.