Searching for the early benthic phase (EBP) of the European lobster: a trans-European study of cobble fauna

The re-stocking or enhancement of Homarid populations has been the focus of several research projects in recent years. However, despite being able to successfully rear lobsters in captivity, there are few reports of newly settled European lobsters (Homarus gammarus) in the wild. This is of serious concern for fishery managers when trying to ascertain if restocking or enhancement programmes are successful at the fishery level. Based on published work from the western Atlantic seaboard, cobble and boulder substrata have been identified as an important nursery habitat for early benthic phase (EBP) American lobsters (Homarus americanus). This paper, based on an E.U. funded research project (LEAR), describes the results of quantitative airlift suction sampling from cobble habitat in Norway, Ireland the U.K., and Italy. In total, 67 m² of cobble was sampled, but no EBP lobsters were found. Overall, crustaceans and molluscs were the most abundant species in all countries. While the collective densities of animals per m²of cobble were similar to that of the United States, the species diversity in Europe was noticeably higher. Among the crustacea, the reptant decapods dominated at all sites. These findings tend to support the modern day `exclusion hypothesis' that competition and predation from other species limits the successful recruitment of EBP European lobster to the benthos. The results highlight the need to go beyond the single species approach to understanding the factors that influence the recruitment of Homarus gammarus.