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The Decline of Seagrass Meadows

Zostera! 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?

Bay Scallop on Eelgrass

Argopecten on Zostera! Bay Scallops, Argopecten irradians , have developed a very close relationship with eelgrass, Zostera marina. As larvae, they are passively transported, and tend to settle in eelgrass meadows when the current is dampened by the 3D structure of the seagrass. This same 3D structure provides post-set juvenile scallops a spatial refuge from predation. Even as larger juveniles and adults, scallops are capable of, and have been shown to, actively select eelgrass habitats.

Other species also use eelgrass

grass shrimp A number of other species utilize eelgrass as a habitat. Included are grass shrimp, like the Palaemonetes pugio, other decapods such as blue crabs, bivalves such as hard clams, gastropods (snails), and numerous fish species, including winter flounder, tautog and cod.

What I’ve Learned:

The Peterson Lab Family. Photo by Rebecca Kulp

So I spent the last few weeks attending conferences (and, actually leave Sunday for another one).  First, I spent time in Norfolk, Virginia, at the Benthic Ecology Meeting.  While there, I saw many good presentations, and learned many new things.  First, I learned that my former student Kate Lavelle (well she was an undergrad who worked on my project), who is now completing her Master’s work at the Harte Research Institute at Texas A&M Corpus Christi, gets to do awesome things in submersibles! I went to a bunch of talks regarding trophic ecology – including ones about predation as well as non-consumptive effects, and luckily my talk was on the first day in the Trophic Ecology session.  I talked about using back of the envelope calculations to get an idea whether or not we would expect to see scallops on the bottom based on predator density and habitat complexity.  I think it went well.  But the one thing I took home from that talk was hope you don’t have to talk at the same time as Emmet Duffy, as it is my understanding that about everyone else at the conference was at his presentation.  I saw a couple of cool talks about species interactions and their importance in the context of ocean acidification, including one by my labmate, the illustrious Amber Stubler.  I also saw a very interesting talk by Paul Gribben from Australia about a species of seagrass which actually leads to enhanced predation on clams.  Weird! I also attended plenty of seagrass and restoration talks.  And of course, the Film Festival, which you can watch all the videos here.

Then I headed to Seattle for the National Shellfish Association meeting.  That was pretty good as well, but between 3 days of talks previous to that and the jet-lag from flying across the country, it was hard to absorb any information.  I was able to catch a few interesting plenary talks, including one by Ray Hilborn and another by Bruce Menge.  Otherwise, I went to a lot of restoration talks, most of which focused on oyster reefs, which were useful since it seems like I might be doing some of that this summer in Shinnecock Bay.  There, I essentially gave the last talk of the conference, about multiple predators and impacts of habitat complexity, which I think went well.  I also learned that Seattle is very hilly, more-so than I would have imagined, but it also has a really awesome bar called the Taphouse Grill, which had 160 beers on tap! Overwhelming! But all in all, a good trip.

Now, I have to prepare my presentation for the United States chapter of the International Association of Landscape Ecology meeting in Newport, Rhode Island, which I give next Monday morning! Uggg! Why did I think it was a good idea to give 3 different presentations at 3 different conferences in a 3 week span? I guess it’s kind of my going away party, as I am planning on graduating this summer.  July defense!

 

 

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