The Fish Community of Cobscook Bay, Maine: Patterns of Abundance and Diversity

Cobscook Bay, in eastern Maine, is the site of a pilot tidal power deployment by Ocean Renewable Power Company.  This deployment raises significant questions concerning the impacts of these devices on the Bay’s fish community, where published scientific knowledge is lacking.  This study, designed with assistance from local residents and fishermen, examines broad-scale fish presence and distribution.  In 2011 sampling occurred in May, June, August, and September using bottom (n=31) and mid-water (n=44) trawls, seines (n=79), and fyke nets (n=22).  We documented 6,000 individuals and 32 species.  Similar sampling is planned for 2012 and 2013.  Habitat use, seasonal presence, and relative abundance will be used to describe the Bay’s fish community.  Preliminary analyses reveal basic patterns in the most frequently captured species.  For example, Clupea harengus and Osmerus mordax appeared in different habitats as new year-classes emerged and spawning occurred.  Seasonal shifts in habitat use, year-class, and size were observed for Gasterosteus aculeatus and Pseudopleuronectes americanus.  The three years of data will be analyzed using indices of diversity such as Simpson’s index and abundance biomass curves to describe the fish community, providing a baseline for comparison once major tidal power development occurs in the Bay.