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...

Thursday, January 15, 2009

"Nub" scallops

Most bay scallops live less than 2 years, and so a concentric growth ring is usually only laid down once. Typically seed scallops reach a size threshold, 35-55mm by the end of their first growing season. However, some scallops are less than 20mm when the growth ring is set. These could be the product of fall spawns, and there is some thought that these scallops don't spawn before they are large enough for their first harvest, that is, they are likely to live into and spawn in a 2nd year. Some populations consist of more than 50% of these "nub" scallops. This has been a particular problem in places like Nantucket, where large portions of scallops have small growth rings. In order to harvest a bay scallop, it must have a clear growth ring, however, "nub" scallops have such small rings, they often appear as ringless adults. This has drastically shrunk the harvest of scallops in this area. That is, until this year, when an emergency regulation was passed to save the harvest. The legislation stated that now scallops could be harvested if they were greater than 2.5 inches in shell height OR if they had a 10mm growth ring - this means that ringless adults (nub scallops) can be harvested if they are greater than 2.5 inches. I don't know if I agree about this legislation, mostly because very little is known about nub scallops and their potential importance for spawning in the 2nd year. I did think it was interesting that bay scallops have been in the news recently.

The photos were taken by Steve Tettelbach and borrowed from a poster presented at last year's 100th annual National Shellfish Association meeting.


merc said...

The regulation is a little different than what you and our "quick to the press" newspaper wrote. The new regulation still requires ALL scallops to have an annual ring. The only difference is that those with rings less than 10mm now must also have a shell height of 2.5 inches or greater. It is actually more restrictive than the previous rule and protects about 60% of nubs this year that would otherwise be open to harvest.

John Carroll said...

sorry for the miscommunication... thank you