By Calhoun Bond
Jul 10, 2015
In August 2014, DNREC published new regulations concerning Shellfish Aquaculture Development Areas in the Inland Bays; one of the SADAs (designated IR-B, planned for oyster aquaculture) comprises 29 acres of Beach Cove, just south of the Indian River Inlet.
Beach Cove is quite small, approximately half mile by three-quarter mile, and is surrounded by residential communities, except for the south end whose shorelines are preserved natural areas. SADA IR-B will comprise more than a quarter of the navigable area of Beach Cove - and almost all of the open water area frequently used for recreation and navigation.
My neighbors and I from around the cove were greatly surprised and saddened to hear of this new development (public notifications were not well advertised). As a biologist who has had a residence near Beach Cove for 50 years, I would like to make this argument: While Beach Cove is a great spot for water recreation and nature study, it is a terrible spot for culturing oysters.
Please consider these facts: The tidal waters at site IR-B are too shallow to allow for sufficient submersion of oysters, particularly at low tide, when depths rarely exceed 18 inches or less in many spots.
During the winter, Beach Cove freezes over completely at multiple times and sometimes for weeks. This past winter (2015) we had 6 complete freezes, one freeze lasted almost 22 days.
Aquaculture Site IR-B abuts and may actually be inside Excluded Seafood Waters (excluded due to public health concerns).
These parameters suggest that any oysters living (for a time) in Beach Cove must deal with daily tidal exposures to very shallow water (if not open air) and with multiple, extensive winter freezes. Beach Cove oysters would also be living in or near waters that are excluded-for-public- health. These do not sound like very good conditions for the long-term culture of oysters for human consumption.
It is instructive to recall the fate of an experimental oyster reef that was established by DNREC at the James Farm Ecological Preserve, very near to Beach Cove.
The reef, constructed in 2001, experienced severe mortality events due to adverse conditions: these events were in 2003 (summer algal bloom: 40% mortality) and in 2004 (winter freezes: 70 percent mortality). The project was discontinued in 2006, after tests showed extensive infection by the Dermo parasite (probably due to oyster stress) at the reef.
One can foresee similar problems at the proposed site in Beach Cove. We know that oysters filter the water and remove particulate matter, but it is an overstatement to claim that oyster aquaculture will clean the waters of Beach Cove. Oyster filtration rates seem impressive in controlled tank studies, but studies on the effects of cultured oysters on wild sites are inconclusive. For example, recent studies from the Cheasapeake Bay show that scientists can find no clear relationship between cultured oysters and cleaner bay water.
We should also remember that clams, which already live in Beach Cove, have similar filtration rates to those of oysters. Clams, with their digging, are much more resilient to weather and water changes than oysters, who can’t move at all as adults. Perhaps we should leave the clams alone to filter Beach Cove (and provide wild-caught food for some of its visitors). My neighbors and I around Beach Cove support sustainable aquaculture, but the above arguments strongly suggest that SADA site IR-B is not a sustainable site for oyster aquaculture.
DNREC should thus exclude Beach Cove from its Aquaculture plan and concentrate on other SADA sites (such as those in Rehoboth Bay), which present much more viable and sustainable conditions.
Calhoun Bond, Ph.D
Professor of Biology