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USE OF SHALLOW WATER HABITATS BY ECONOMICALLY VALUABLE FISHES AND CRUSTACEANS
Citation:
Cicchetti, G. USE OF SHALLOW WATER HABITATS BY ECONOMICALLY VALUABLE FISHES AND CRUSTACEANS. Presented at National Association of Fisheries Science, Groton, CT, January 13, 1999.
Description:
I investigated nekton use of bay-exposed fringing salt marsh habitats at the Goodwin Islands NERRS location (York River, Virginia) in two separate studies. In a 1995 project, depositional-edged salt marshes and the adjacent non-vegetated habitats were sampled with quantitative 1.75 m2 drop rings and 1.75 m2 throw rings. These areas were found to be important to blue crabs (Callinectes sapidus) for recruitment, feeding, and refuge. The depositional salt marsh edge was particularly valuable in providing a combination of feeding and refuge for small blue crabs, with mean densities of 3.9 ? 0.2 (SE) inds m-2. Juveniles of economically valuable fish species were captured in these habitats, but at low densities (typically 0.3 ? 0.1 inds m-2). Patterns of habitat use by marsh resident fishes at depositional edge sites were found to differ from what has been reported in the literature for other geographic regions. In a 1997 study, erosional-edged marsh and non-vegetated habitats were sampled using a quantitative 80 m2 enclosure trap that was targeted towards larger nekton. An underwater video camera study found that nekton were concentrated at the erosional marsh edge. Large blue crabs were the biomass dominant species, and 1.2 ? 0.3 (SE) blue crabs (mean carapace width 65 mm) representing 11.0 ? 2.9 grams dry weight (gdw) were caught per linear meter of marsh edge. Economically valuable fishes were abundant (0.7 ? 0.2 inds m-1, 2.9 ? 0.8 gdw m-1) and diverse. These fishes included spot (Leiostomus xanthurus), spadefish (Chaetodipterus Jaber), bluefish (Pomatomus saltatrix), southern kingfish (Menticirrhus americanus), summer flounder (Paralichthys dentatus), permit (Trachinotus Jalcatus), spotted seatrout (Cynoscion nebulosus), silver perch (Bairdiella chrysoura), striped bass (Morone saxatilis), American eel (Anguilla rostrata), Atlantic croaker (Micropogonias undulatus) and pigfish (Orthopristis chrysoptera). I conclude that both erosional and depositional salt marsh edges can provide important habitat for economically valuable nekton. These findings directly link bay-exposed marshes to commercially exploited deeper water ecosystems.