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...
Friday, October 3, 2008
You've got to suffer is you want to sing the (Spat collection) blues!
Wow, first, I did not realize it has been such a long time since my last update. I have been very busy with writing a manuscript and trying frantically to finish up the field season (although I still have another month to go). A few weeks ago, I went out sampling for my recruitment squares. If you remember, my last post about them suggested that I should not abandon hope, as I was finally starting to see some small spat. I was, of course, very excited. Well, I was dealt a crushing blow. Two weeks ago we were seeing a very high number of spat in collectors within Hallock Bay, which lead me to believe that I would most certainly find spat this time around on my mats, at least more than the last time, even if it wouldn't be alot. So, extremely excited, my advisor, Dr Brad Peterson, and I headed out to my field site to collect my recruitment squares from my grass mats. Now, this is no easy feat, and requires a few hours in the water searching for them (I guess I could have planned the relocation aspect a bit better) and a couple more hours going through the samples. As always, I have my own set of spat collectors at my site which I use as a "control;" the idea here is that if there are larvae in the water, I know they will recruit to the collectors, and that will give me a decent idea of what I might expect to see. I always process the collectors before my squares, so I know what to look for (ie, should I see any scallops at all? what sizes should I be looking for?). Well, as it turns out, I had a fairly large number in my collectors, which had me thinking awesome! My recruitment experiment is finally coming together! 2 hours later, I had a decidedly different opinion on my recruitment experiment: FAILURE!!! We found only 1 scallop spat on all the squares collected. ONLY 1!!! This is not nearly what I was hoping for, and certainly doesn't bode well for what I thought would be a fairly big portion of at least 1 chapter of my thesis work. It is pretty disheartening, putting in all that work ( a full day's worth of work for 2 people) to only come away with 1 scallop. Granted, the supply in the system might not be very high, and I might not have received numbers good enough to run any sorts of statistical analysis. However, 1 scallop? On a day I expected to see many more, given what had happened on the last time I sampled my squares and what we saw in our spat collectors. But no, it is a failure. I have one more collection scheduled, next week, and then I can truly decide which is a bigger failure, my recruitment experiment, or the New York Mets season.
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.