Abstract
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 and 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 marsh fragmentation, but was instead related to local-scale patterns of habitat availability, including presence and type of vegetation. In tethering experiments to examine predation rates on juvenile blue crabs across habitats, predation rates were lowest in SAV compared with marsh edge or bare sediment. While direct effects of marsh fragmentation on local-scale patterns of blue crab abundance were not observed, marsh fragmentation will likely have indirect effects on blue crab populations through changes in habitat availability. Unless SAV expands into newly created open water areas, providing an alternative nursery habitat for blue crabs, continued marsh fragmentation and loss are expected to have negative impacts on blue crab populations and fisheries through a decrease in available nursery habitat.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.