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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.

Trawling on the “Jungle Queen,” Part Three!

The RV Peconic, aka "Jungle Queen"

While it has nothing to do with my research, trawling is one of the most fun things I get to do, so I jump at every opportunity that I can to make a trip (as I have blogged about a few times before).  Recently, we took some summer camp kids from Southampton Bath and Tennis Club out on the boat to do some fun trawling.  This group of kids was one of the most enthusiastic group I have been on a boat with.  They were all excited to get out on the water, and didn’t hesitate to dig into the tray full of algae and seagrass to pick out all the little critters.

Kiddies digging into the catch

The catches didn’t yield too much out of the ordinary – flounder, crabs, tomcod, sticklebacks, pipefish, shrimp, the usual things we typically get.  But we did get a lot of them.  We seemingly were constantly pulling baby winter flounder out of the catch tray (I want to guess they were all young of the year, but there was a range of sizes, so it could be a couple of year classes).  There were a lot of blue crabs which we removed before the kids could dig in.  And there was so many pipefish, including many pregnant males (yes, male pipefish carry the young, and apparently, will abort eggs from “unattractive” partners).

baby flounder and another fish

 

Kiddies around the holding tank

We even caught a few tropical fish.  This time of year we typically catch tropical fish which come up in the Gulf Stream and get transported into Long Island south shore waters in meandering eddies.  We typicallys start to see butterfly fish, some gray snappers, occasionally small groupers, cowfish, burrfish, and file fish.

 

Filefish

But the real star of the show this week was the seahorse.  Seahorses are native to NY waters, as the lined or northern seahorse, Hippocampus erectus, is found from Nova Scotia to Argentina.  It uses a variety of structured habitats, however, on Long Island, they typically utilize eelgrass as their habitat.  They use their tails to hold onto shoots of grass and sit still to wait to suck up little unsuspecting critters like small amphipods and shrimp to eat.  Like their cousins the pipefish, male seahorses also carry the eggs.  Lined seahorses are listed as “vulnerable” by the World Conservation Union’s red list of endangered species.  They used to be common in Long Island waters, but loss of their primary habitat, eelgrass, has caused populations to be reduced.  Hopefully, with the help of the seagrass group from Cornell and their work with seahorses, these magnificent sea creatures can return to having large, healthy populations around NY.

Seahorse!

3 comments to Trawling on the “Jungle Queen,” Part Three!

  • I had no idea all of these fellows could be found in my backyard/neighborhood bay. Do you have any books to recommend to someone who wants to learn more about critters in the Peconic?

    • Hi Erin, thanks for the question. Probably the best book is one called Marine Animals of Southern New England and New York by Howard Weiss. I picked it up when I was an undergrad at Southampton College when it was still LIU. Best yet, my labmate just bought a copy of amazon barely used for $14 bucks. It doesn’t have everything, however, it has all the really common macro things you will find. Good luck!

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