Aquaculture and waterfowl
URI graduate student Tori Mezebish holds a black duck she tagged as part of her research on the interactions between waterfowl and aquaculture facilities. (Courtesy photo)
From ecoRI News (ecori.org)
As aquaculture operations expand in Narragansett Bay and Rhode Island’s salt ponds, questions have arisen about how ducks and geese are impacted by the facilities. To begin to answer these questions, a University of Rhode Island doctoral student is tracking the movements of local waterfowl.
“There haven’t been any Rhode Island studies yet, but studies on the Pacific Coast have found issues with diving ducks getting tangled up in netting used by aquaculture, and birds that have been deterred from areas that might otherwise be good habitat because of the activities of aquaculture operations,” said Tori Mezebish, a native of Maryland who is collaborating on the project with URI professors Peter Paton and Scott McWilliams and officials from the Rhode Island Department of Environmental Management.
She noted previous studies have also observed sea ducks such as eiders and scoters, which feed on mollusks, preying on oysters and other shellfish being grown by aquaculturists.
“There’s also been some positive associations, like ducks and geese eating some of the aquatic vegetation that accumulates on the cages,” Mezebish said. “It’s a mixed bag of how the birds might interact with aquaculture.”
Last winter, Mezebish attached transmitters to 30 black ducks and 30 brant, a species of goose that lives in salt water. This winter she will deploy an additional 30 transmitters on common goldeneyes, a diving duck. All three species are common during winter in Narragansett Bay, the state’s salt ponds, and adjacent salt marshes.
Most of the brant have returned from their breeding grounds in the Arctic, and several of them spend every day with dozens of other brant on the lawn at Colt State Park in Bristol. Others are spending most of their time in the upper bay and Providence River. The black ducks are just beginning to return to the area from Maine and southern Canada, and the early arrivals have been tracked to the salt ponds and the Galilee area.
Mezebish is tracking the movements of each bird using a GPS unit on their transmitters to see how much time they spend near aquaculture facilities. She is also observing the birds in the field to validate the GPS data and see what the birds are doing around the shellfish farms.
“The goal is to understand what is important to these species outside of the aquaculture facilities,” she said. “Maybe brant need shallow areas with submerged vegetation, so that may not be the best place to put an aquaculture lease.”
In addition to Mezebish’s study, URI postdoctoral researcher Martina Müller is conducting land-based surveys throughout the year to see what other kinds of birds may be interacting with aquaculture facilities.
“Ultimately, we want to provide recommendations about the good and not so good places for aquaculture leases to be placed,” said Mezebish, who became interested in waterfowl research as an intern at the Pawtuxet Wildlife Research Center in Maryland, where she hand-reared ducklings used in the center’s research activities.
When the project is complete, Mezebish hopes to use the study as a springboard to study related questions about other conflicts and interactions between waterfowl and humans.