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...
Tuesday, October 21, 2008
Another day, another 100,000 scallops
Or something like that... Last Thursday, October 16th, I went diving out in Flanders Bay. We were doing a bottom survey of a previous free release spot for scallops, since we were preparing to release ~100,000 seed scallops as part of the restoration efforts going on in Long Island. Flanders for a very long time sustained a sizeable scallop population even inthe absence of eelgrass (Zostera marina). But land use changes in addition to the brown tides more than likely led to their demise in that area. Luckily, a year after last years plantings, there were still ~ 1 per square meter, much lower than stocking, but still a decent number. After surveys, we set up an area to plant new scallops, at ~ 100 per square meter. We hope to dive on the site once more before it gets too cold, and then start again in the spring. Hopefully this will help jump-start a population in Flanders. Additionally, I saw some really cool things... including a porgy trying to eat leftovers from a whelk feeding, a whelk eating a newly planted scallop, and a large northern puffer, which are rare nowadays due to overfishing. Oh and this mean looking guy. And tons of cool shells. All in all, it was a pretty cool day of diving. Not only was I a part of the free release, I was able to see some cool things, like direct predation, swimming scallops (which are impossible to get a photo of, in case you were wondering why there isn't one) and that puffer really made my day.
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
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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.