Horseshoe Crabs on Oyster Farms

We know that fences around farms and homes can change how wildlife species move across a landscape, but what happens if the farms are under water? In 2018, the Munroe Lab began experiments and surveys to look at this question on oyster farms in the lower Delaware Bay. The wildlife species of interest: horseshoe crabs – the ancient, and ecologically important mascot of the Delaware Bay. The studies focused on testing whether crabs use intertidal oyster farm habitat differently than they do areas where farms are absent, and if the farms might prevent crabs from reaching critical beach spawning habitat. Studies are ongoing, and results to date show that crabs don’t use farm habitats any differently than non-farm habitat, and they can easily move among farm structures to reach spawning areas.

You can watch sonar video of crabs walking around an oyster farm, and a timelapse of some experiments

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Crabs milling around oyster farm racks, with beach spawning habitat in the background

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DMCS undergraduate intern Josh Daw measures crabs prior to an experiment testing their ability to move over and around farm gear