Could offshore clamming become a thing?
By Kitta MacPherson
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| Laura Steeves (far right), a former postdoctoral student, collaborates with a fishing partner to prepare a surfclam cage for deployment, while Ailey Sheehan, a lab manager, activates sensors to facilitate the launch. Sarah Borsetti/Haskin Shellfish Research Laboratory |
A study led by marine scientist Daphne Munroe has
shown that Atlantic surfclams can be successfully farmed in the open ocean.
Her research, published in the North American Journal of Aquaculture, proves that offshore aquaculture is not only possible but promising. This method could help meet the increasing demand for seafood while protecting wild clam populations.
“We’re among the first to show that offshore clam farming
can really work,” said Munroe, an associate professor in the Department of Marine and Coastal Sciences in
the Rutgers School of Environmental and Biological Sciences. “It’s exciting
because it opens the door to a new kind of business for New Jersey’s farming
and fishing industries.”
The study was funded by a grant from the National Oceanic
and Atmospheric Administration and was done in partnership with commercial
fishing companies.
“We didn’t do this in a lab,” Munroe said, emphasizing the
importance of working with industry partners. “We did it in the real world,
with real fishermen. That’s what makes the results so meaningful.”
Aquaculture is the practice of farming fish, shellfish and
other aquatic organisms. It’s similar to agriculture, but instead of growing
crops on land, farmers raise seafood in water. Most aquaculture takes place
near the shore in protected bays or in artificial ponds and lakes.
These areas are easier to manage and safer from storms, but
they are crowded with other user groups like homeowners and boaters and can be
subject to poor water quality which can hinder farm operations. Offshore
aquaculture avoids these challenges, Munroe said, by using the vast, cleaner
waters of the open ocean, where there is more room and less potential for
pollution.
Members of Munroe’s team wanted to test whether surfclams,
which are large, hard-shelled shellfish that live buried in sandy ocean
bottoms, could be raised offshore, where space is more available. The clams,
commonly used in chowders and fried clam strips, are an important part of New
Jersey’s commercial fishing industry.
Researchers placed more than 300,000 young surfclams into cages in ocean waters miles off the coast of New Jersey. They tested the clams in both spring and fall to see how the seasons affected their growth and survival.
The cages used in
the study were specially designed to protect the clams in several ways. They
kept the shellfish safe from predators such as crabs and fish, which are common
threats in the wild. The cages also helped reduce the buildup of sand and sediment,
which can make their meat gritty.
By keeping the clams elevated off the ocean floor, the cages
allowed cleaner water to flow through, resulting in clams with very little sand
in their meat, making them ideal for eating steamed or on the half shell. In
addition, the cages were built to withstand strong waves and rough ocean
conditions, making them reliable even during storms.
The researchers
found that clams put out in spring grew faster and had higher survival than
those put out in fall. Spring conditions were calmer, with fewer storms and
less sediment, making it easier to retrieve the cages and check on the clams.
Another important finding was that clams in less crowded cages were healthier
and grew better, showing that space matters when farming shellfish.
Munroe said that the results were especially encouraging
because they showed that offshore aquaculture could be both productive and
environmentally responsible. “We saw that the clams were not only surviving,
but they were also thriving,” she said. “And the meat quality was excellent,
with very little grit. That’s a big deal for consumers and for the industry.”
She said there are still hurdles to surmount, such as making
sure the gear lasts in challenging weather and properly navigating and
following governmental regulations. But Munroe said the potential is huge.
“This could be a
win-win,” she said. “We can grow more seafood in a sustainable way and support
local jobs.”
Rutgers scientists who contributed to the study included:
Laura Steeves, a former postdoctoral researcher at the Rutgers Haskin Shellfish Research Laboratory and
now at the Flødevigen Research Station in Norway; Sarah Borsetti, a fisheries
researcher at the Haskin Shellfish Research Laboratory; and Rachel Davitt, a
doctoral student in the Department of Marine and Coastal Sciences.
