Restoring oyster habitat to the Raritan Estuary
More than 100 years ago, the harbor, an arm of the Raritan Bay, was abundant with oysters.
Years later, a combination of over-harvesting, pollution and disease decimated the local oyster population after 1900, but members of the NY/NJ Baykeeper are working to bring the oysters back.
The organization, which works to protect, preserve and restore the Hudson-Raritan Estuary, launched the Keyport Harbor Oyster Reef Project, a program that will gradually restore the oyster habitat to the urban estuary.
“This is the only oyster project of this scale in northern New Jersey waters and the New York City area,” said Baykeeper Debbie Mans, executive director of the NY/NJ Baykeeper. “Oysters are in a steep decline in the harbor area. They are not harvesting oysters anymore from the Raritan Bay, but we still have a clam industry here. We would like to do future restoration efforts to make sure we don’t lose the oysters in the New York Harbor area.”
Working in partnership, the NY/NJ Baykeeper, along with Rutgers University, the Hackensack Riverkeeper and Raritan Riverkeeper, made plans to create a living oyster reef constructed out of rebar, a type of steel, and fashioned into a vertical structure that would allow oysters to bond and attract different organisms to spawn. The structures were set into the water on Sept. 18.
“As oysters grow, they attach to each other, so this vertically accreting structure within the bay bottom is attractive to fish and other marine habitats,” Mans said. “It’s also a great habitat because unlike clams or mussels that just grow flat, these will eventually grow out of this structure and provide that varied habitat.”
The quarter-acre reef is divided into different sectors in order for scientists to observe the progress of the oysters. The structures contain perforated mesh bags that resemble miniature cages, which allow water and the current to flow through so that oysters can feed, harden and grow.
“Oysters are natural filter feeders,” Mans said. “They are helping filter the water for water quality and to help clarify it.”
Cement “reef balls,” circular designs made of calcium carbonate to attract different sea life, were also constructed.
“We place the whole thing into our aqua culture tank, and the oyster larvae set,” Mans said. “The oysters attach themselves and they start growing off the structure. You may see oysters growing about 20 millimeters off the reef ball already.”
Inside the mesh, the cages contain seed oysters, or juvenile oysters, that were grown over the summer and are not attached.
“These are oyster larvae that set on clam shell because they need a hard surface to set on,” Mans said, pointing at the shells and finding a tiny black crab already crawling on the structure.
“See? These are the types of things we would like to happen.”
Greg Remaud, deputy director of the NY/NJ Baykeeper, said oysters must be placed in cages in order to stick together. The bags will also be monitored for growth and survivability.
“You need structures to hold the oysters so the stockpiles of shells don’t move around,” Remaud said. “We are not trying to bring oysters back for food harvest, but we are for their incredible filtering purposes. Other oysters and organisms will grow on top and will create this whole incredible reef ecosystem.”
By utilizing the man-made reef, the NY/NJ Baykeeper wants to enhance the distribution of oyster larvae to other parts of the harbor and the Aberdeen and Union Beach shallows.
According to Mans, the 10-year-old oyster restoration program is the largest project the NY/NJ Baykeeper organization has ever undertaken.
In the future, the organization hopes the project will improve water clarity, quality and stability for the Raritan Bay shoreline. The Hudson-Raritan Estuary is home to more than 150 species of fish and shellfish, 330 bird species and 15 million people.
“We would like to identify other locations that we could do additional research on,” Mans said. “When the oysters mature, they spawn, and then they find other reefs to set and then you get sort of a necklace of reefs along the Bayshore. They also act as shore protection against storm surges and waves.”
She held up one of the mesh bags and observed the oysters already joining together.
“You can do restoration in this area in your own backyard,” she said.
BY JACQUELINE HLAVENKA