Back in 2007, a landmark paper in Science changed how everyone thought about cownose rays. These smiley aquarium ambassadors suddenly became the most hated fish in the Atlantic. As the press release for that paper stated:
A team of Canadian and American ecologists, led by world-renowned fisheries biologist Ransom Myers at Dalhousie University, has found that overfishing the largest predatory sharks, such as the bull, great white, dusky, and hammerhead sharks, along the Atlantic Coast of the United States has led to an explosion of their ray, skate, and small shark prey species.
“With fewer sharks around, the species they prey upon — like cownose rays — have increased in numbers, and in turn, hordes of cownose rays dining on bay scallops, have wiped the scallops out,” says co-author Julia Baum of Dalhousie.
The study, which described the evidence for a shark-ray-shellfish trophic cascade leading to a collapse of the Chesapeake Bay scallop fishery, became an instant classic. “This is the first published field experiment to demonstrate that the loss of sharks is cascading through ocean ecosystems and inflicting collateral damage on food fisheries such as scallops,” said Ellen Pikitch, then a professor at the University of Miami Rosenstiel School of Marine and Atmospheric Science and executive director of the Pew Institute for Ocean Science, in the original press release.
The study had all the ideal components of blockbuster research: it was led by one of the world’s most preeminent fisheries biologists. It played to both sides of an age-old rivalry; it had a strong shark conservation message, providing much needed data to support the claim that sharks are vital ecosystem components. Yet at the same time, the study hit home with locals and fishermen, explaining why a once lucrative fishery was reduced to a mere shell of its former glory. The phenomenon it described—a top-down trophic cascade, with sharks as the key species—had been hypothesized for years but never demonstrated. And, whether intended or not, the paper provided an easy and achievable solution for the area’s woes: fish the rays instead of the sharks, and everyone wins. Frankly, it just made sense.
“People thought ‘Finally! Some evidence for this top down control by sharks,’ and accepted it without critically reading and reviewing the paper,” said Dean Grubbs, an elasmobranch ecologist with Florida State University. Though Grubbs and others had issues with the paper’s methods and conclusions, especially regarding the reproductive biology of rays, their initial worries were drowned out by the loud trumpeting the paper received. “We were concerned that this could quickly get out of hand,” Grubbs said. And it did. The paper became one of the most well known studies ever conducted in marine ecology, garnering almost 900 citations in the last 9 years.
