Nursery habitat use by juvenile blue crabs in created and natural fringing marshes

Abstract

Climate change and coastal development pressures have intensified the need for shoreline protection. Nature-first approaches that use natural habitats, particularly marshes, are being promoted globally as ecologically-beneficial alternatives to grey infrastructure. The ability of these novel shorelines to provide nursery habitat to blue crab (Callinectes sapidus), an ecologically and economically important species along the Atlantic and Gulf coasts of the United States, has not been fully evaluated. We quantified the abundance and size distribution of juvenile blue crabs from a chronosequence of living shorelines (created fringing marshes) spanning 2 to 16 years in age since construction compared with paired natural fringing marshes in the southern Chesapeake Bay. Both created and natural fringing marshes are used by blue crabs as primary nursery habitats. Despite interannual differences in abundance, young blue crabs (≤ 2.5 cm carapace width) were observed in similar densities and sizes at living shoreline and natural marshes. The age of the living shoreline was not related to blue crab density, indicating that even the youngest living shorelines (2 years) provided nursery habitat. The potential for living shorelines to serve as nursery habitat for an economically important species may provide additional incentive to implement these nature-based approaches for climate change adaptation.