Ecological evaluation of Sedge Island Marine Conservation Area in Barnegat Bay : Final Report, 2014
Date
2014-08-29
Date Removed
Journal Title
Journal ISSN
Volume Title
Publisher
Trenton, N.J. : New Jersey Department of Environmental Protection, Division of Science, Research and Environmental Health
Abstract
Conservation zones are important for maintaining the sustainability of ecosystems and
populations of economically important species. The relative ecological value, especially for
economically important species, of the Sedge Island Marine Conservation Zone (SIMCZ) in
Barnegat Bay, NJ was assessed by comparing the following inside the SIMCZ with areas outside the conservation zone: (1) population structure of adult blue crabs using commercial-style traps, (2) reproductive potential of both sexes and brood production of adult female blue crabs, and (3) species diversity and abundance of fish and select decapod crustaceans, particularly blue crabs, in three habitats (seagrass, macroalgae, and unvegetated) using throw traps. Commercial-style
trap sampling indicates that the SIMCZ had greater abundance of male blue crabs, a sex ratio
that is more skewed towards males, and a greater proportion of ovigerous females than mid and
western-bay locations outside the SIMCZ. There was no evidence that reproductive potential
(e.g., sperm stores) or female brood production differed among the locations. Using a complementary data set from a co-occurring project; as compared with physically similar areas, the SIMCZ contained: (1) more adult blue crabs than other SAV-dominated areas along the
north-south axis of Barnegat Bay, (2) more adult females, especially egg-bearing females, than adjacent, SAV-dominated areas with similar access to Barnegat Inlet, and (3) more male blue
crabs than open bay habitats within an east-west zone of the Bay. Taken together, these results suggest that the SIMCZ is an important area for both male and female blue crabs, particularly females that are spawning. Throw trap sampling indicates that species diversity, the total
abundance of organisms and the abundance of juvenile blue crabs were similar inside the SIMCZ as compared to outside the SIMCZ. In contrast, juveniles of two economically important fish species (winter and summer flounder) were more abundant inside the SIMCZ than outside the SIMCZ. Habitat was far more important than location in accounting for the variation in species diversity, total abundance and the abundance of blue crabs. In general, structured habitats (SAV and algae) contained more species, individual organisms and blue crabs than open areas. Sampling for this project occurred before and after “Superstorm” Sandy, thus annual differences
may reflect potential Sandy effects. Annual differences in blue crab abundance between and
within locations suggest that the SIMCZ provided a buffer against the potentially negative
effects of Sandy. Throw trap sampling suggests that the SIMCZ contains habitats that are
ecologically valuable and are helping to sustain valuable species.
Description
Keywords
New Jersey, Ecosystem health - New Jersey - Barnegat Bay, Blue crab - Conservation, Crustacea - Conservation, Sedge Islands (N.J.) - Conservation, Barnegat Bay (N.J.) - Conservation