Abstract

Recently we have begun to understand the importance of inshore hard-bottom substrate, including oyster reefs, to estuarine fish communities in the Gulf of Mexico, especially in the context of identifying Essential Fish Habitat (EFH). However, habitat loss, disease, overharvest, and the failure to replace shell have severely decreased the amount of high-relief oyster reefs available to finfish. The purpose of this project is to establish an artificial high-relief oyster reef in Barrataria Bay, Louisiana and monitor its use by commercially and recreationally important finfish, including spotted sea trout (Cynoscion nebulosus) and Atlantic croaker (Micropogonias undulatus). Finfish and invertebrate communities on the artificial reef were compared to a mud bottom reference site. We have also examined site-specific trophic linkages by enumerating gut contents and performing stable isotope analysis of select species. Preliminary results indicate a seasonal difference in the numbers of individuals found at both sites. Species diversity also varied by season, with highest diversity occurring in summer months. Variation in fish abundance and species diversity between sites was low. Dietary analysis indicates there are significant differences in the diets M. undulatus between sites (p < 0.05), but only slight differences in the diets of C. nebulosus. Atlantic croaker diets consisted of mud crabs (Xanthidae) and unidentified crabs on the reef, and bivalves and fish over the reference site. Spotted sea trout consumed mostly unidentified fish and anchovies by number, and penaeid shrimp by weight.

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