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Nature Blog Network

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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.

All across the interwebs

So I’ve read a lot of interesting things in the last day or so, and figured now was as good as time as any to do another… drumroll please… LINK DUMP!

First, this is totally cool.  I SCUBA, but I am not talented enough to pay an instrument, so there is no way I could join with this band.

I’ve already talked about sharks where they shouldn’t be, and fellow blogger Lyndell Bade mentioned to me stories of bull sharks up the Mississippi River.  This recent news article demonstrates just that – sharks caught 140 miles up river!

An engineer looked toward basking sharks for inspiration on a more efficient hydroelectric turbine. Nice.

Talk about itchy – sea lice on salmon have been linked to British Columbia fish farms.

Coral cores from Australia reveal that it is likely to receive more inclement weather.

And I thought it was the pretty swords – some recent research suggests that male swordtails excrete pheromone-packed urine in the presence of females to attract a mate. FYI – I am a fa of swordtails – having grown up with fish tanks and working at a pet fish store for most of high school an college.  These livebearers were some of my favorite fish.

RickMac over at Deep Sea News blogs about sustainable sushi.

Over on the mothership (read SFS), Andrew puts out his newest installment of the SFS Gear Review, and Dave blogs about catch and release shark fishing.

And there is this video by the world famous fish biologist George Burgess about the worldwide increase in shark attacks:

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