Zostera marina is a seagrass species, commonly known as eelgrass, that is found on both coasts of the United States, as well as in Europe. Unfortunately, Zostera is disappearing all over the place, including right here in New York. This could have devastating impacts on animals that rely on eelgrass as foraging grounds, or, as is the case with scallops, use it as a refuge from predation. This is its story, as seen through the eyes of an aspiring graduate student...
Saturday, October 4, 2008
Scallops?! You wanna talk about scallops?!
So I went to measure my scallops on Tuesday for my growth experiment, which if I had to say, is going fairly well. I conducted a similar experiment last year and ended up with good results, so I added more mats this year and hoped to see much of the same. It was a long day (at Southold by 8:30, leave the dock by 9:30, back tot he dock by 5:30, leave Southold by 6:30), and I ended up that night with a killer headache, ended up sleeping for 12 straight hours, which never happens to me, but that is a horse of a different color. The water has cooled down considerably, but it was none-the-less a nice day diving on my grass mats. As soon as I got to the bottom, I saw a huge winter flounder, we are talking dinner for 4 (well maybe not quite that big, but big), and of course I didn't have my catch bag or my camera, but I still tried to grab it by its tail and it swam away. Aside from the flounder, the usual suspects were all out - tautog, cunner, porgies, sticklebacks, gobies, spider crabs, mud crabs, and even blue crabs. And this knobbed whelk, crawling along the bottom, leaving his mucous trail along the way. Oh, and adult scallops. I found one in my mat that at first glance looked like a really big seed. As it turned out, it was a scallop with a small growth ring, sometimes called nub scallops. These scallops are usually spawned late in the year (October) and only grow a few millimeters until their growth stops for the winter. The next season, they catch up to the other scallops, and end up around the same size. I also saw this guy, who was posing for pictures. All in all, nice day on the water, and my scallops are looking good.
I am a marine biologist that is currently attending graduate school at the School of Marine and Atmospheric Sciences, Marine Sciences Research Center, of Stony Brook University, New York. I am very interested in marine ecology and have been focusing my studies on bay scallop interactions with their habitats. I plan to investigate various anthropogenic impacts on bay scallop populations for my PhD dissertation. This blog will highlight the details of my graduate research, from bay scallop-eelgrass interactions as previously mentioned, to alternative habitats for scallops, such as Codium, to trophic cascades, and more. Enjoy!
Eelgrass is an important habitat for multiple marine species, including the bay scallop
Scallop on Artificial Eelgrass
This tethered juvenile bay scallop attached itself to my artificial eelgrass...
The decline of eelgrass meadows
Eelgrass, Zostera marina, is a flowering, marine vascular plant that remains submerged all the time. This is quite a feat for vascular flowering plants, and only a few dozen species world wide are capable of growing completely submerged in a marine environment. Eelgrass creates and extremely important habitat, its upright structures and complex root system create a 3-D living space for many different types of animals. It is (or was) the dominant habitat forming SAV (submerged aquatic vegetation) throughout much of the coastal waters in the northeastern United States. Unfortunately, for various reasons, eelgrass meadows have seen drastic declines, and in many locations eelgrass only exists in a mosaic of small patches. This is extremely bad news as many of the important, and formerly important, commercial and recreational fisheries of the northeast US are dependent on Zostera at some part of their life cycle as a nursery and foraging ground. Some of the species are finfish like tautog, bluefish, fluke, winter flounder, porgies, while others are shellfish such as blue mussels, hard clams, oysters, bay scallops, and blue crabs. Many of the aforementioned species support or once supported vibrant fisheries. Many of those fisheries have collapsed, also for various reasons. However, is it possible there is a link between the crash of the fisheries, the decline of Zostera and the failure for recovery on both ends?
Eelgrass, Zostera marina, a temperate seagrass species, providing a vital habitat for numerous marine species
Scallops in eelgrass
Some adult bay scallops we planted in eelgrass for a free release survival experiment we conducted
If you live in coastal zones, urge your local and state representatives to push for environmental issues that you are concerned about. Ask for more stringent rules regarding the destruction of existing eelgrass. Encourage restoration programs to be set-up. Call your state and national representatives and ask them what they are doing to protect our precious resources. Practice safer boating and know the undersea terrain - i.e., don't drive your boat in very shallow water. Avoid clamming in eelgrass meadows.