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, August 30, 2008
Working in the coal mine... (on the barge)
Well, yesterday I worked on the barge - its a boat built by S.P.A.T. volunteers working with the Cornell Cooperative Extension of Suffolk County. It is used mainly for the scallop restoration work, and is equipped with a motorized winch and a star wheel for hauling up lines weighed down by hundreds of lantern nets full of scallops. This time of the year, the majority of scallops in the nets have spawned at least once, so they need to be relocated to make room for the next batch of scallops to grow-out before overwintering. It can be a labor intensive process as the nets are heavily weighed down by fouling organisms, in particular sea squirts. It is essentially pulling up a net full of scallops, as well as hundreds of little water packets (the squirts) so the nets get pretty heavy. Then, most of the squirts need to be knocked off before the bags can be opened and the scallops dumped on deck, so it is also a very messy process, and sometimes, not very easy as an invasive sea squirt, Styela clava, have very strong attachment points to the nets and to shells within the nets. Once the nets are cleaned and the scallops dumped onto deck, they need to be released to the bottom. Some of the scallops are pretty fouled (the latter two were collected a day earlier), but it adds to the camoflage for the scallops on the bottom. The nets also often have lots of little guests in them, including hundreds of grass shrimp and mud crabs, spider crabs, cunner and tautog, and even sculpin. Sometimes we get pipefish and seahorses from the nets but this is more rare. Additionally, some of this years seed (scallops from earlier spawns this year) have set on the nets and grown very well. All in all, it was a nice, messy day on the boat with some interesting things to see, including this awesome schooner, the Mary E, on our way home.
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.