It Wasn’t The Rays’ Fault After All

Feb 17, 2016

  Back in 2007, a study published in the journal Science claimed that an explosion in the population of cow nose rays—kite shaped creatures that return to the Chesapeake Bay every spring—was causing the crash in an already fragile oyster population.

It was said these prehistoric looking brown rays with the whip-like tails glided into Chesapeake Bay every spring to reproduce and devoured oysters, clams and scallops while they were here.

It reached the point that Virginia established a cownose ray fishery to try to cull the population. Cownose Ray tournaments sprung up in Maryland and Virginia in which hunters rode in the bows of boats targeting large, pregnant females.

But a Florida State University study published this week says that may have all been a mistake. It wasn’t the rays’ fault after all.

  In his 2007 report, acclaimed fisheries biologist Ransom Myers blamed overfishing of large sharks along the Atlantic Coast for the sudden increase in the number of cownose rays. But Dean Grubbs, lead author of the new report, says that just 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,” he explains. “When you're only producing one juvenile per year it's impossible to increase at such a rapid rate.”

So, Grubbs took another look at the data in the 2007 study and basically said hold it a minute. Bay scallop and oyster landings had collapsed years before Myers claimed the cownose ray population increased.

The oyster stocks had collapsed by 1990, he said. “And the cownose ray increase didn’t happen until the late 1990s.”

Now, Grubbs says, fisheries managers have to come up with “some precautionary limits on what is taken until we can assess what is sustainable.”

That means drafting some rules about taking a species fisheries managers know little about and educating a divided public, some of whom see the rays as a Chesapeake icon and others who see them as a pest to be dispatched with bows, arrows and baseball bats.