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...

Sunday, October 3, 2010

Jaws:Fire Island?

Well not quite.  White sharks have been receiving a considerable amount of press this summer in the northeast (see here, here, here, and here). Apparently, there were so many sightings that the US Coast Guard issued a white shark advisory, warning people of the northeast that (shocker!) there are white sharks in the water. However, these sea creatures hardly pose a threat to Long Island bathers, Dr. Demian Chapman, shark biologist from the Institute for Ocean Conservation Science, School of Marine and Atmospheric Sciences, Stony Brook, assured the general audience at Southampton College last Friday night.

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

1 comment:

Ben and Carrie Tracks said...

So great to stumble across your blog on the Nature Blogs Network - we're new to it as well.... loving this shark post and looking forward to following more :)