Zostera marina is a seagrass species, commonly known as eelgrass, that is found on both coasts of the United States, as well as in Europe. Unfortunately, Zostera is disappearing all over the place, including right here in New York. This could have devastating impacts on animals that rely on eelgrass as foraging grounds, or, as is the case with scallops, use it as a refuge from predation. This is its story, as seen through the eyes of an aspiring graduate student...
True, the northeast used to be a hot spot for white sharks. There were a great many sightings in the 50s and 60s, sighting of both juveniles, adults and even some pairs that were believed to be mating. While little is known about the white sharks around Long Island at this time period, Dr. Chapman said that some researchers believe this might have been a spawning and nursery ground. That being said, there is little data on white sharks from this time period other than sightings. White shark fishing then became quite common, and some of the largest white sharks ever caught were landing on Long Island, particularly out in Montauk, where Captain Frank Mundus was renowned for being a top shark fisherman.
What happened over the course of the past decades is that white shark populations have dwindled in the northeast. While there might be some debate as to the magnitude of the decline, I think most researchers will agree that it is significant. Dr. Chapman is looking to use genetic tools to get a grip on how small (or big) the white shark population might be. Using samples from around 50 sharks, the data thus far shows that northeast white sharks have a low genetic diversity, indicative of a species that has experiences a considerable decline, also known as a bottleneck. This could be potentially devastating to coastal ecosystems along the US, as these animals are apex predators in the coastal food web.
So maybe the white shark advisory shouldn't have been alerting the public about their presence in the waters of New England, but perhaps, they should have been warning us about their disappearance.
That all being said, I am no shark biologist, and the above information was from my notes at the lecture. To learn more about sharks, you should check out some other websites, like the one about New England Sharks, and other blogs by people in the know, such as this entry at Ya Like Dags
I am a marine biologist that is currently attending graduate school at the School of Marine and Atmospheric Sciences, Marine Sciences Research Center, of Stony Brook University, New York. I am very interested in marine ecology and have been focusing my studies on bay scallop interactions with their habitats. I plan to investigate various anthropogenic impacts on bay scallop populations for my PhD dissertation. This blog will highlight the details of my graduate research, from bay scallop-eelgrass interactions as previously mentioned, to alternative habitats for scallops, such as Codium, to trophic cascades, and more. Enjoy!
Eelgrass is an important habitat for multiple marine species, including the bay scallop
Scallop on Artificial Eelgrass
This tethered juvenile bay scallop attached itself to my artificial eelgrass...
The decline of eelgrass meadows
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?
Eelgrass, Zostera marina, a temperate seagrass species, providing a vital habitat for numerous marine species
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Scallops in eelgrass
Some adult bay scallops we planted in eelgrass for a free release survival experiment we conducted
If you live in coastal zones, urge your local and state representatives to push for environmental issues that you are concerned about. Ask for more stringent rules regarding the destruction of existing eelgrass. Encourage restoration programs to be set-up. Call your state and national representatives and ask them what they are doing to protect our precious resources. Practice safer boating and know the undersea terrain - i.e., don't drive your boat in very shallow water. Avoid clamming in eelgrass meadows.