The influence of abiotic and biotic factors on two nudibranchs feeding upon Membranipora membranacea in the southern Gulf of Maine

The abiotic (temperature and flow rate) and biotic factors within fouling communities at three marinas located along the southern Gulf of Maine from June to December in 2010 and 2011 were surveyed. The goal of this study was to determine what is driving the recent population increase of the nudibranch, Corambe obscura, and whether the native nudibranch, Onchidoris muricata, is transitioning prey species. In addition, the affects of temperature on aspects of C. obscura\u27s life history were determined by laboratory experiments. Results suggest that abiotic factors influence basic community members such as the kelp host, Saccharina latissima, and the invasive bryozoan, Membranipora membranacea, biotic factors such as settlement substrate and prey species are more important to the predatory nudibranchs. Consequently, while C. obscura\u27s presence would not be possible without the presence of M. membranacea, temperature has allowed them to have high turnover rates and reproduction which increases their population size