The Effects of Season and Proximity to Fringing Mangroves on Seagrass-Associated Fish Communities in Charlotte Harbor, Florida

Abstract

Little has been published on habitat use by fishes in Charlotte Harbor, one of Florida's largest-and still relatively pristine-estuaries. Multivariate analyses of data from 21.3-m-seine samples (1996-2000) were used to examine spatiotemporal patterns of seagrass habitat use by Charlotte Harbor fishes. Two habitats (mangrove-associated seagrass shorelines and offshore seagrass flats) were examined. Throughout the year, the mangrove-seagrass habitat was distinguished by Menidia spp., Mugil gyrans, Eucinostomus harengulus, and Floridichthys carpio, and the offshore seagrass flats habitat was distinguished by Bairdiella chrysoura, Orthopristis chrysoptera, and Cynoscion nebulosus. The dry season (Dec.-May) was distinguished by Lagodon rhomboides, Leiostomus xanthurus, and O. chrysoptera in both habitats and by Mugil cephalus in the mangrove-seagrass habitat. The wet season (June-Nov.) was distinguished by Lucania parva, F. carpio, and Fundulus grandis in the mangrove-seagrass habitat and by Eucinostomus gula, Microgobius gulosus, C. nebulosus, and E. harengulus in the offshore seagrass flats habitat. Eucinostomus spp., Anchoa mitchilli, and Strongylura notata were abundant in both habitats during the wet season. In general, many species were collected in both habitats and were widely distributed in the estuary. Various combinations of four environmental variables (i.e., water temperature, salinity, dissolved oxygen, water depth) and their coefficients of variation were well correlated with the biotic community patterns. These results show that different fish communities use different seagrass habitats in Charlotte Harbor, depending on the season and the proximity of the seagrasses to fringing mangroves.