Feeding ecology and bioturbation: determining the ecological role of Euspira lewisii

The burrowing, predatory snail Euspira lewisii is being removed from intertidal habitats due to its reputation as an economically damaging species to shellfish aquaculture. Here, the objectives were to examine feeding ecology and determine the functional role of a poorly understood species. Feeding experiments and shell assemblages showed distinct prey preferences, avoid ance of the commercially valuable Manila clam, a low, species-dependent feeding rate and a limited yearly consumption of the clam population. Exclusion experiments demonstrated increased sediment compaction, silt content and nutrient accumulations and decreased water content when E. lewisii is absent. Homogenized biological communities in cages resembled less diverse areas. These results demonstrate that E. lewisii is a low impact predator and acts as an ecosystem engineer to the benefit of other organisms. These results can be used to advise shellfish growers that control measures are not necessary and they will benefit from the maintenance of a healthy ecosystem.