Abstract

The mangrove prop-root habitat of Salt River Bay, St. Croix, U.S. Virgin Islands, was sampled monthly from October 1990 to April 1993 to assess the importance of mangroves as nursery habitat for economically important finfish species. The mangrove fringe of turbid area were sampled with standardized baited fish traps, while less turbid areas were sampled with visual transects. Trap sampling sites were defined based on habitat type, extent of human activity, and development; two sites had undeveloped, extensively-covered mangrove shorelines, while two sites had reduced mangrove cover and were partially impacted by development. Transect sites encompassed available mangrove shorelines with low turbidity. ; Individuals caught in traps represented 40 species and 19 families. The most common families were Gerreidae (36% relative abundance, two species), Pomadasyidae (20%, seven species), Lutjanidae (16%, six species), and Chaetodontidae (14%, two species). Individuals observed in transect represented 48 species and 26 families. The most common families were Lutjanidae (38%, six species), Pomadasyidae (34%, eight species), Gerreidae (10%, two species), and Pomacentridae (5%, seven species). Species relative abundance varied by site among both trap and transect areas. Mean number of species and individual s per trap were higher in sites with reduced mangrove cover. This was likely due to less available shelter, making the traps more attractive in areas with less prop-root habitat. This hypothesis was supported by transect data; mean number of species and individuals per transect were higher in areas with more mangrove habitat. The majority of species were represented by juveniles, and mean length was stable over time. One species (Acanthurus chirurgus) exhibited an annual peak in abundance, while several other species had a single abundance maxima. The Salt River Bay mangrove habitat provides important mangrove nursery habitats for many fish species, most notably economically important species, and should be inc1uded in fisheries management plans.

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