Habitat use by early life-history stages of fishes and crustaceans along a changing estuarine landscape: differences between natural and altered shoreline sites

The recent population explosion along the coastal zoneof the southeast United States and the Gulf of Mexicohas accelerated the development rate of waterfrontproperty, and particularly along the Gulf Coast ofMississippi. We compared use of pristine and alteredshoreline habitat by early life-history stages of fishand crustaceans to assess the potential effects ofthis development. Monthly beam trawls were taken at13 sites along shoreline habitats characterized byJuncus/Spartinamarsh, natural beach, and areasaltered by bulkheads and rubble. A total of 52,068fish (n = 48 taxa) and 288,715 crustaceans (n = 24taxa) were collected during a two year study. The mostabundant fish groups included gobiids, sciaenids,clupeids, and engraulids. Crustaceans, excluding thecopepods, were numerically dominated by mysids, bothcaridean and penaeid shrimps, and crabs (Callinectesspp.). Demersal residents were dominatedby Gobiosoma boscand Palaemonetessp.whereas clupeiformes, sciaenids and penaeid shrimpswere dominant among the nektonic and demersaltransient species. These taxa were least abundantalong stretches of shoreline altered with bulkheads orrubble, and were generally most abundant in shorelinehabitats fringed with Juncus/Spartinagrasses.This general pattern in nekton relative abundanceparallel the low diversity (reciprocal of Simpson'sDominance Index) values adjacent to altered marsh tohigh values adjacent to pristine marsh or beachhabitats, suggesting that habitats adjacent to alteredmarsh sites are less frequently used as nurseryhabitat compared to natural sites. These data supportthe hypothesis that shorelines adjacent to marshhabitat are critical to various life history stages ofecologically- and commercially-important species,illustrate the influence of altering natural marshhabitat on resident/transient nekton, and providequantitative data for resource managers in thecontinued efforts to preserve the complex estuarinemarsh landscape.