Last week, I culled all of our one-year-old clams that were around ¾ of an inch or larger and placed them in a separate bucket in the upweller. It was time for these clams to finally get in the mud. When clams grow to this ¾ inch size, they need to grow under pressure. If not, the clams’ shells would become very thin making them more susceptible to break or open up, causing the clams to die. When out in the flats, the clams are surrounded by silt and sand that constantly press against their shells. This pressure forces the clams to direct their energy towards building thicker, stronger shells, preventing them from breaking easily. We are unable to grow the clams to legal harvesting size ( 2 inches) in the upwellers because there, they wouldn’t be under constant pressure.
Last Thursday morning, when the tide was low, Mike Pinkham and I headed over to the old lobster pound behind the Shellfish Resiliency Lab. First, we wanted to know if there were any clams already in the mud of the old lobster pound. If so, it would be a good indicator that the surrounding environment was suitable for our clams to grow and thrive. We didn’t find many clam holes, but the few that we found had clams greater than three inches. These clam sightings assured us that our clams had potential to thrive.
With over 350 clams to plant, we decided to split the clams into two treatments. Our first treatment was planted fairly off shore while our second treatment was planted closer to the shoreline. To plant our clams, we took a garden rake and raked off the first inch of mud. Most green crabs lie in this first layer of mud and by raking it up, it would be easy to spot the crabs and remove them before seeding our clams. Then, just like in a garden, we made rows (about 1 foot apart) in the mud, creating a space to plant our clams. We placed the clams around 4 inches apart in the rows with their siphons sticking up. After getting stuck in the mud a few times, we finally finished planting – around 170 clams in the first treatment and around 180 clams in the second treatment. Our first treatment was complete, but our second treatment still needed one more finishing touch. We chose to put a netting over the clams for our second treatment. The goal of this netting is to try to prevent green crabs from predating on our clams. In the upcoming fall, we hope to compare treatments and determine whether the clams with netting over them had a better survival rate than the clams without netting over them. Not only are we trying to seed the clam flats, but we are also using this as an opportunity to run an experiment that will help us determine whether it is necessary to place netting over all of our clams in the future.
