Changes in Distribution and Abundance in Two Potentially Competing Benthic Predators, Blue and Lady Crabs Following a Barrier Island Breach

Great South Bay (GSB), a large, temperate lagoonal estuary along the South Shore of Long Island, NY is home to two significant populations of predatory crustaceans, blue (Callinectes sapidus) and lady (Ovalipes ocellatus) crabs. Historically, lady crabs were limited to the higher salinity waters near Fire Island Inlet while blue crab populations have cycled through periods of high and low abundance. Both species are opportunistic omnivores with significant dietary overlap. In October 2012, Hurricane Sandy breached the barrier island, resulting in increased salinity levels throughout the bay. This perturbation has allowed the lady crab to increase its range within the bay, resulting in increased potential competitive interaction with blue crabs. Utilizing 2014-15 trawl survey data, we examined each species’ abundance and distribution throughout the bay. Both species show large increases in abundance across their length range in July. We used length and apron stage to estimate size at maturity for both blue and lady crabs. This work will improve knowledge of life history characteristics for an existing and potentially expanding blue crab fishery in New York.