Determining the Fate of the Cownose Ray
Oyster restoration efforts around the Chesapeake Bay come with a variety of concerns including one that returns every spring with the annual migration of the cownose ray. A new Florida State University report published by Nature is using new data to refute claims that cownose rays are responsible for the collapse of the oyster industry.
In his 2007 report, acclaimed fisheries biologist Ransom Myers blamed overfishing of large sharks along the Atlantic Coast for a population explosion of cownose rays. But Dean Grubbs, lead author of this new report, says that isn't biologically possible.
“Cownose rays require about seven years to reach sexual maturity and then they only produce one offspring after a 12-month gestation period. When you're only producing one juvenile per year it's impossible to increase at such a rapid rate. “
Grubbs took another look at the data in the 2007 study and found bay scallop and oyster landings collapsed years before Myers alleges the cownose ray population increased.
“By 1990 the oyster stocks had all collapsed for the most part and the cownose ray increase supposedly didn't happened until the late 1990s.”
For a time, Virginia established a fishery to cull the population. And in both Maryland and Virginia, popularity increased for cownose ray tournaments, where hunters ride the bows of boats targeting large pregnant females entering the Chesapeake Bay to give birth in the spring.
“We need some precautionary limits on what is taken until we can assess what is sustainable.”
Fisheries managers now have the difficult task of determining the fate of a species they still know little about. One of the biggest hurdles is educating a public that is divided with some seeing the cownose ray as a Chesapeake Bay icon and others a pest to be dispatched with bows, arrows and a baseball bat.