Laurie J. Bauer

Influence of Benthic Features and Fishing Pressure on Size and Distribution of Three Exploited Reef Fishes from the Southeastern United States

Abstract Distribution, habitat preference, and size structure were examined for three commonly targeted bottom fishes (black sea bass Centropristis striata, gag Mycteroperca microlepis, and scamp M. phenax) in the southeastern United States. Fish communities and bottom characteristics of limestone ledges within Grays Reef National Marine Sanctuary (located centrally along the southeastern continental shelf) were surveyed. Black sea bass occurred at 98% of the ledges and were evenly distributed throughout the sanctuary in much-higher numbers than either gags or scamps, which were concentrated at only 11% of the ledges. Gag or scamp presence was most strongly related to height of ledge undercut, whereas abundance of black sea bass was best explained by percent cover of sessile biota. In addition, lower abundance of black sea bass occurred in the presence of either gags or scamps, which are generally larger than black sea bass. In all three species, an abrupt decline in abundance was observed for size-class...

Asymmetric impacts of two herbivore ecotypes on similar host plants.

1. Ecotypes may arise following allopatric separation from source populations. The simultaneous transfer of an exotic plant to a novel environment, along with its stenophagous herbivore, may complicate more traditional patterns of divergence from the plant and insect source populations.