Blue crab abundance and survival in a fragmenting coastal marsh system

Louisiana’s coastal marshes are becoming increasingly fragmented due to sea level rise, subsidence, reduced sediment inflow from the Mississippi River, and saltwater intrusion. Many commercially and recreationally fished species rely on the marsh system as nursery habitat, and the resilience of species to further marsh loss and marsh fragmentation is uncertain. We examined the impacts of marsh fragmentation on the blue crab, Callinectes sapidus, a species supporting one of the largest fisheries in coastal Louisiana, which uses marsh edge as nursery habitat. Juvenile and adult abundances were quantified in multiple habitats (bare sediment, marsh edge, and submerged aquatic vegetation [SAV]) within an actively fragmenting coastal marsh. Adult blue crabs were sampled using crab pots, while juveniles were sampled using a throw trap. In general, blue crab density was unrelated to the ranges of marsh fragmentation sampled here, but were instead related to local-scale patterns of habitat avail...