"Nucella Lapillus L."Imposex after Tributyltin (TBT) Ban and Population Connectivity Studies

Abstract

The gastropod Nucella lapillus is the most common predator in the European Atlantic intertidal rocky shores. Its populations have been exposed to the pollutant tributyltin (TBT) for years, which induced the development of male sexual characters onto females (imposex). At high concentrations, it produces sterility and can cause population to collapse. The use of TBT has been regulated until its total ban in 2003. N. lapillus is the sentinel organism for its biomonitoring. This thesis add new information to the data collected in Galician coast since 1996, and explores the effectiveness of the legislation. Furthermore, population recovery in the marine environment greatly rely on the arrival of new individuals. N. lapillus is a direct-developer and is assumed to have a limited dispersal. Here, AFLP markers were used to investigate the population genetic structure of N. lapillus to elucidate its actual dispersal capacity and thus its ability to recover. Sampling was designed to test if hydrodynamic conditions have an influence on the resulting genetic pattern. In addition, a genome scan for outlier loci was performed among the AFLP markers to explore if wave-exposure conditions were promoting local adaptation under isolation. Finally, the temporal genetic stability was investigated by sampling several generations.