DAY 4: Friday August 15, 2003
I have just returned from a wonderful vacation and participation in a teacher institute on the west coast. The institute, using GIS to map habitat suitability, is a computer program that would be perfect for this project, which is something that I got very excited about. Much of the work last summer centered on conducting a baseline survey of shellfish habitat (mainly bay scallop) in Point Judith Pond, with use of a GIS data may be viewed using maps. Teams assessed eelgrass coverage, shellfish densities, abundance of crustaceans and sediment grain size. Using GIS one could basically take these layers of data, rank them in terms of importance and use several calculations to build a map of several layers to determine the choicest habitat for the bay scallops.
Although the quahogs have definitely grown, the oysters look like they have been dining on steroids. At one time in Rhode Island there was a thriving commercial oyster fishery, apparently wiped out mainly by the Hurricane of '38 and subsequently by habitat loss and degradation. These oysters look pretty happy and don't seem to be lacking for nutrient rich food. A viable renewable oyster fishery may again be a reality in the Ocean State.
The oyster restoration component of the NCSRP utilized a method called remote setting. Early last spring Karin had a tractor trailer load of sea clam and quahog shell delivered to the work site from the Blout seafood company in Warren. It is commonly known that oysters, as well as all other bivalve mollusks, go through a juvenile stage known as a veliger. The veliger is planktonic and in the case of the oyster floats around for approximately two weeks eating and gaining weight (sounds like parts of my summer vacation). After this period of rapid growth the veliger undergoes a metamorphosis, drops to the bottom of the water column and begins to scout around for a suitable substrate on which it desires to spend the rest of its days. The preferred substrate of the young oyster is some sort of shell material.
After several days the shell bags were brought back to the NCSRP facility and placed in a designated nursery area adjacent to the dock. The shell bags were placed on ribar platforms, this keeps the oyster spat off the bottom and away from hungry predators. They are also exposed to the atmosphere at low tide which inhibits the growth of biofouling organisms.
Biofouling is a major consideration when culturing filter feeding bivalves. Many of the biofoulers, sea squirts, tunicates and sponges are also filter feeders and compete directly with the shellfish for food, oxygen and space.
I have become thoroughly engrossed with the wonderful variety of organisms that make up the biofouling community. They are colorful, plentiful, represent several phyla, exhibit a diversity of shapes and are strangely beautiful.