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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.

Hunting lion(fish)… Celebrity Blog

A few months ago I made a post about lionfish being fished an eaten as a way to eradicate these invasives from the Caribbean.  One of the places where this was being done is Jamaica, and if you remember correctly, last week I posted about a tropical course that undergrads from Stony Brook get to take in the laid back paradise.  My labmate, Amber Stubler, is there as well, working on her dissertation research, but also hunting and eating lionfish.  So I thought she should tell us about it (also, all the pictures are Amber’s):

After much groveling, John finally convinced me to write a “celebrity” blog about my trip to Jamaica. Rather than bore you all with the details of my sponge research (which you can read about here, here and here), I decided to write about another issue going on throughout the Caribbean- the invasion of lionfish, and what the Jamaicans are doing about it. For those who did not know- Lionfish (Pterois volitans) are native to the Pacific and likely arrived in the Caribbean via the aquarium trade (however ballast water transmission cannot be ruled out). The earliest sightings of lionfish in the wild (confirmed by USGS) were in southern Florida in 1992, and since then lionfish have been reported from Long Island to Venezuela. The USGS website has a really awesome animated map of the invasion here, which goes from 1992-2010.

 

I have been coming to Jamaica on a regular basis since 2007, and saw my first lionfish in 2009. I specifically remember taking about a thousand pictures of it, because even the marine scientist in me cannot resist a pretty fish picture. Since then, their populations have exploded, and when I say exploded, I mean I saw one in 2009, and on this trip I could easily count between 15-35 fish in an area the size of a football field underwater. So at this point you should be saying, “Amber, what’s the big deal with these lionfish, after all they are pretty and quite frankly the Caribbean could use a few more fish.” The problem is that they are voracious predators who will eat small invertebrates, juvenile fish, and anything else that will fit in their greedy mouths. This poses a threat to all the indigenous reef species as the lionfish eat all of the native species’ food, or just plain eat all of the native species. Also these guys pack powerful venom in the spines on their fins, which will ruin anyone’s dive/snorkel adventure. And since these guys are invasive, they have few natural predators which means they are free to roam about the Caribbean.

This, my friends, is where we come in.

We’ve all learned a valuable lesson that the best way to get rid of a fish species is to eat them (examples: cod, Atlantic salmon, etc). So what’s a country like Jamaica to do? Eat ‘em to beat ‘em (which by the way is the Bahamas official lionfish slogan). The Jamaican Ministry of Agriculture and Fisheries has begun an annual lionfish derby where prizes are awarded for the most lionfish caught over a 3-day period. They also hold seminars on how to safely catch, clean, and cook lionfish. Here at the Discovery Bay Marine Lab, staff members regularly go on lionfish hunts, bringing back dinner for their families and samples for Dr. Dayne Buddo, who studies invasive species at the Centre for Marine Sciences, University of West Indies. Dr. Buddo has spearheaded (no pun intended) many public outreach events teaching locals about the biology of the lionfish, the impacts on the ecosystem, and how to treat a lionfish sting. He also shares some of his favorite recipes, and cooks the fish up for skeptical Jamaicans.

After seeing Dayne spear several lionfish during one of our “fun” dives (ie not for research purposes), I decided it was time to take part in the action. So I broke out my shiny new speargun (specifically bought for this trip), and started wreaking havoc on the lionfish at my study sites. Over a course of our 2-week trip we managed to kill about 36 lionfish, and although that doesn’t really sound like a lot, we actually only brought the speargun out about 6 times, which means that our average was about 6 fish per dive. The largest we caught was 13 inches, and roughly 1 lb, certainly not a record, but a lionfish of that size can produce 30,000 eggs at a time, so I like to think that our killing spree helped save the reef from a few future lionfish. The great part about this whole kill-every-lionfish-you-can ideal is that it is uniting the fishermen against one species and will hopefully help eliminate/decrease the lionfish population here in Jamaica. Jamaica is already one of the most overfished reefs that I have ever seen, so having the fishermen focus on an invasive species gives the native fish a break from fishing pressure and keeps food in people’s mouths.

You can do your part too! Check out this awesome cookbook to become a full-fledged invasivore, and donate to a great non-profit organization dedicated to marine conservation.

6 comments to Hunting lion(fish)… Celebrity Blog

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