BIRON, S.A.*; ELZEY, S.P.; HOWELL, W.H.; University of New Hampshire: Comparison of feeding habits between adult and juvenile smooth skate, Malacoraja senta, and the possible influence of tooth morphology

The smooth skate, Malacoraja senta is a small species indigenous to the Gulf of Maine (GOM). Due to the lack of biological data and the decline in population, management measures have instituted a ban on this species by the commercial fishing industry. As part of a larger and ongoing research project to help fill this void in biological information, the diet of adult and juvenile M. senta was investigated. Skates ranging in size from 65-39cm in total length were collected from the GOM during the months of June, July, August and September 2002. After each collection period, skates were anesthetized, then the stomachs were removed and stored whole in 10% formalin for further analysis. In order to compare differences in diet, individual stomach contents were separated into taxonomic classes, which included amphipoda, teleostei, polychaeta, and crustacea (crabs and shrimp only). Wet and dry weights for each taxonomic class for each skate were obtained and analyzed using an ANOVA. Preliminary results suggest that the diet of adults and juveniles consists of different percentages of each taxonomic group. For example, adults consumed more crustaceans than juveniles for the four months examined, while juveniles consumed more amphipods than adults (p<0.001). Preliminary investigation of tooth morphology suggests the differences in diet could be related to variation in tooth structure. Differences in both tooth angle (p<0.001) and the length to width ratio (p<0.001) were found to exist between adults and juveniles. Further analyses to be presented include examination of seasonal and sex related differences in diet as well as the index of relative importance for each taxonomic food group.