Although some oyster farmers consider
rays as oyster-eating machines, in fact “
oys-ters…were not found to make up a significant portion of the diet of cownose rays,”
according to Fisher’s NOAA report. More
common as prey are thinner-shelled
species, such as razor clams, macoma, and
A.J. Erskine, President of the Virginia
Seafood Council, said he does not believe
that oysters make up only a small portion
of the ray diet. But Erskine agreed that
alternatives to killing rays are worth investigating. The crucial thing, he said, is that
action is taken to control rays. He
explained that rays not only consume oysters, but also rip up underwater grasses
that are important habitat for fish, crabs,
and other forms of life.
DESCRIPTION: Brown to olive green, kite-shaped body with a long, whip-like tail and
square snout that resembles a cow’s nose.
SIZE: Wingspan can reach three feet, weight
can approach 50 pounds.
LIFESPAN: 13 to 18 years.
DIET: Mollusks, including oysters, razor
clams, macorma, and softshell clams.
RANGE: Present in the Bay from May through
REPRODUCTION: Mates in late summer before
heading to southern coastal waters in the fall.
Females give birth to a single 11- to 18-inch
pup the following June.
“For the sea grasses, for all these shellfish,
we need to be able to control this predator,” Erskine said. “And if we don’t, then I
don’t think we are going to be able to realize aquaculture in the state of Virginia and
Maryland to its full potential.”
Impact on oyster restoration
Tommy Leggett, CBF’s Virginia Oyster
Restoration and Fisheries Scientist, said
that recent history provides vivid examples of how rays can be a problem for not
only commercial oyster aquaculture, but
also for oyster restoration projects.
ers launched a program to eradicate oyster-eating bat rays, the campaign appeared to
backfire and cause more oyster mortality,
according to ray researchers and Sonja
Fordham, President of Shark Advocates
International. As it turned out, the California
rays were not eating many oysters, but they
were eating oyster predators, such as crabs,
which became more numerous.
Charles “Pete” Peterson, Professor of
Marine Sciences at the University of North
Carolina, argues that overfishing of sharks
removed a predator that kept ray populations in check. “The answer is better shark
management, and we are moving toward
that,” Peterson said.
In 2006, CBF planted 650,000 oysters as
part of a restoration project in the
Piankatank River, only to see the oysters
quickly devoured by rays, Leggett said.
Two years later, CBF worked with the
Cowart Seafood Company to plant about a
million oysters in the York River, and rays
again vacuumed them up.
“This issue is not new,” said Dean Grubbs,
a researcher at Florida State University.
“About every 10 years for the last 40 years,
there has been an outcry from the oyster
industry that ray populations have
increased and are destroying oyster beds.
But there have always been a lot of
cownose rays in the Chesapeake Bay.”
In the end, the solution may have many
components. Among the steps needed are
studies of ray populations, to see if they
are on the rise, and how vulnerable they
might be to overfishing. Nonlethal techniques to repel rays from oyster farms
and restoration projects could work
alongside a limited harvest of rays, as
long as the harvest is carefully managed
to ensure sustainability.
“All of the big players (in Virginia aquacul-
ture) have been severely impacted by
cownose rays,” Leggett said. “There are
some proponents who would like to anni-
hilate the whole species. But we need a
more balanced approach to managing the
The explorer Captain John Smith encoun-
tered huge schools of cownose rays. In fact,
a ray famously delivered a venomous sting
to Smith (which was so painful his crew
feared he would die) at a place in Virginia
now called “Stingray Point.”
Harvesting the slow-reproducing rays could
have unintended consequences, conserva-
tionists warn. When California’s oyster grow-
An ecosystem out of balance
A key to resolving the ray-oyster conflict
may be restoring the balance of predators
and prey in the Chesapeake Bay. One theory is that rays primarily fed on soft clams,
until soft clam populations were decimated
by overharvesting and disease—and so
rays increasingly turned to oysters.
Education of the public is also important,
to let people know that those shark-like
tips rising from the water are not signs of
monsters to be feared and hated. The
wings beneath the waves are part of a natural ecosystem older than the Chesapeake
Bay itself that glides with its own peculiar
beauty and grace.
Tom Pelton, an award-winning
environmental journalist, is
Senior Writer and Investigative
Reporter for the Chesapeake