By SUSAN WEST
Charles Peterson links the collapse of North Carolina’s bay scallop fishery to an increase in the cownose ray population.
To test the theory that cownose rays can devour scallop populations,
Peterson, a researcher at the University of North Carolina Institute of
Marine Science, built fences around some scallop beds close to the
rays’ late-summer migratory routes in the state’s
He found that scallops outside the fences nearly disappeared, while
those inside survived at a sustainable level.
Now Peterson is looking at the impact of rays’ feeding behavior on oyster restoration efforts in the state.
“We’re not ready to call in the troops yet, but the cownose can be a real pest,” Peterson said.
Cownose rays possess all the right equipment to hunt down prey like scallops, oysters, clams, and blue crabs.
With wingspans that can reach up to 7 feet, rays glide over the sea
floor, stirring up sand and exposing shellfish. Sensors under
their distinctive snouts alert them to the presence of prey.
And, they have powerful dental plates for crushing shells.
“And when they can’t find scallops easily, they go in like
bulldozers and tear up seagrass beds and habitat,” Peterson said.
He said surveys show that the number of cownose rays is surging all
along the eastern seaboard. A report he co-authored last year
said the population could stand at over 40 million.
That report linked the booming ray population to the decline in the
number of large sharks, like sandbars and hammerheads, since the 1970s.
But not all scientists agree that cownose rays have surged in
abundance, citing the lack of targeted population surveys, or that
sharks eat a considerable number of rays.
“The cownose ray situation is far from clear,” Virginia
Institute of Marine Science shark researcher John Musick told a
reporter for the Bay Journal last year.
Still, the state of Virginia would like to develop a commercial market
for cownose ray, and some restaurants there now offer what they call
Trish Murphey, biologist with the North Carolina Division of Marine
Fisheries (DMF), tasted cownose ray at a Virginia Sea Grant conference.
Murphey said the texture was “pleasant, not chewy,” and the flavor was very mild.
“All of the samples I tried were either marinated or served with
a sauce, probably because the taste was so mild,” she said.
NC DMF director Louis Daniel said a commercial cownose market could
give watermen a new income source and could benefit shellfish
But he cautioned a fishery for the under-utilized species should be limited.
“We’d need to start slowly and get a handle on the
population size and then decide how far down we would want to fish
it,” he said.
Daniel said the fishery would have to be carefully managed due to the
biological characteristics of rays. They are slow-growing, live-bearers
that usually birth just one pup per litter.
“And, right now we don’t have enough information to really
know the complete role of cownose rays in the ecosystem,” he said.