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, August 26, 2008
Do Not Abandon Hope, Ye of Little Faith
So, a few posts back I was disappointed in the lack of scallop spat on my mats and in Hallock Bay in general. We had not really seen any in our collectors which we use to monitor spat in any of the collections, and so I was not so upset that I wasn't finding them on my mats, just figuring they weren't around. I was a little worried though, since scallop recruitment is a part of my research, and I was already thinking about possibilities of new locations for next year. I was ready to give up on the recruitment thing all together, since it is a lot of work to make the recruitment squares, to search for the squares within the mats, and to put new squares back on, not to mention I didn't want to keep wasting fuel for fruitless boat trips to my site. However, after much deliberation, I decided to make a new set of squares over the weekend to put one more set out there, just to be sure I wouldn't miss it. Well we went to the site on Monday to collect my 3rd set of recruitment squares and to replace them with the 5th (and final) set. I also keep a set of spat collectors at the center of my array to make sure scallops are recruiting to the area using a known method for sampling them. I always process the spat collectors first, just so I have an idea of what to expect on my squares. Guess what? Scallop spat in my collectors!! This was exciting. It wasn't a lot, only 16 total out of 3 bags, but I honestly didn't think I would see any. I still wasn't sure what to expect on my mats, but at least I was happy there were spat in the area. After processing all the recruitment squares, I did have spat on the mats! Success!! Well, kind of - we only found 4 total spat on the squares, not quite numbers that I can use for any kind of stats. However, now I know that if there are spat in the area, they will potentially settle on my mats, which was very refreshing to find.
Oh, and there is better news, the spat that we found was mostly small - 2-4mm. This is good, because it means the spawn happened relatively recently, and will probably show up on my next set of collectors. Second, and more exciting, is what we found today - in our spat monitoring we have 5 sites within Hallock Bay where we have sets of collectors, and we found spat at all of them, and in decent numbers (some bags over 20 scallops) and again, many were small. So I am keeping my fingers crossed that I will see much better numbers on my mats during my next collection!
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.