My name is Elizabeth Oliver. I am a 2023 NOAA Ernest F. Hollings Scholarship recipient that allowed me the opportunity to work with the Great Bay’s research team this summer. The goal was to look at the northern expansion of crabs throughout the Great Bay due to warming temperatures. The main marine life I was monitoring were horseshoe crabs, blue crabs, lobsters, and fiddler crabs.
Elizabeth holding osprey fledgling 06/17/24.
A Crabby Imposter
During the month of May and June many volunteers help to do counts along transects at six different sites to help the research team gain an understanding on the number of horseshoe crabs, Limulus polyphemus, (which are arachnids not a crab) that are coming into the marsh during the spawning season. I was analyzing how temperature is affecting when we see the highest number of horseshoe crabs that are coming into the marsh and comparing it to past years. During June, I also wrote the newsletter updating the volunteers weekly on the data that was collected each week.
Horseshoe crab pair with satellite male at GB Discovery Center 06/07/24
Traps, traps, and more traps…
Blue crabs, Callinectes sapidus, are a non-native species to the Great Bay Estuary and have been migrating northward as seawater temperatures rise while the American Lobster, Homarus americanus, has been migrating toward deeper and cooler water in Little Bay and out of the estuary. With the research team we have been deploying subtidal lobster and blue crab traps to spatially locate them throughout the estuary. Not to anyone’s surprise we have been finding most of our lobsters at Upper Little Bay by Goat Island and all of our blue crabs nearby the Lamprey River.
In addition to the subtidal blue crab traps we have also been deploying intertidal blue crab traps across three sites in the marsh to see if blue crabs are present in marsh creeks and pools. Only two blue crabs have been found so far (unfortunately dead), which was the same number of blue crabs that were found in the previous year and at the same site.
Both trapping methods meant a lot of field days for the research team and I gained a ton of experience building blue crab traps, holding different crab species, and becoming very familiar with the annoying invasive green crab, which has also migrated northward due to warmer temperatures.
Elizabeth holding a blue crab 07/22/24.
Elizabeth and Katie McGovern collecting green crab carapace widths 06/19/24
Cameras out on the Marsh!
Fiddler crabs, Minuca pugnax, are another non-native crab that is migrating northward and have been known to cause degradation to low marsh systems turning them into nothing but mud. This could mean trouble for our marsh systems so we set out to find them and understand what impacts they could have on the Great Bay. How we do this is by setting up transects across two sites in the Great Bay, in these transects we have 20 random plots. In the plots we look for fiddler crab burrows, if a burrow is found, we place a burrow scope down the burrow. This scope is a camera able to fit down the burrow to find if a burrow crab is occupying the burrow. This allows us to take pictures of the burrow and gain a more holistic picture of how many fiddlers are occupying our marsh currently. With this I also created a Mini Crab Field Guide to help people identify crabs out in the marsh especially when looking into a very small burrow.
Male fiddler crab in burrow. Picture taken with burrow scope 06/11/24
