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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.

Logging some Bottom Time

Lets see, Thursday we went to the Dunn’s River Falls as a break from the daily grind here at the marine lab.  That was a lot of fun.

Bottom of the falls

Look at me!

Then in the last 2 days I have put in 7 dives, 4 outside the reef and 2 in the lagoon and one on the other side of Discovery Bay.  I have seen many cool things, collected cool shells, so its been pretty fun.  I had some issues with my camera at the Rio Bueno dive yesterday, so my pictures didn’t come out so well, although I was lucky to get a few shots.

 

Peek-a-boo

Anemone Shrimp

Anemones!

Today we did 2 dives on the fore-reed and 2 within Discovery Bay.  Outside the reef I logged over 2 hours of bottom time, and took many, many pictures.  More anemone shrimp, lionfish, gastropods, and lots more.  Enjoy!

Some star

Another goby of some sort

Flamingo's toungue!

LIONFISH!

 

 

 

 

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