By Julia Robins, Staff Writer
Coastal waters are getting warmer, and these warmer temperatures may affect the migratory range of fish. For example, 40 years ago, summer flounder used to stop their northward migration near Virginia; today they travel about 140 miles farther to New Jersey.
“That’s a relatively large shift,” says Chris Kennedy, “and it’s resulted in some pretty significant impacts to the fishery.”
Kennedy, an environmental economist at George Mason University, has teamed up with natural scientists on a Mid-Atlantic Sea Grant-funded project to understand how the summer flounder fishery may change under different climate scenarios. “I think this fishery is a really good example of the complexity and the difficulty of adapting to climate change,” he says.
Currently, summer flounder is managed in a way that Kennedy says is “not necessarily realistic.” The fishery is managed as a single stock, despite the fact that it spans from the southern border of North Carolina to the US-Canada border. As a single stock, it’s divided up among states into quotas, which are met when catch is landed in the respective state. North Carolina holds the largest quota, a decision made based on its leading summer flounder landings in the 1980s. North Carolina’s commercial fleets now travel as far as New Jersey to catch summer flounder, which they bring back to North Carolina to meet their quota.
While 60% of summer flounder stock is allocated to commercial fisheries, 40% is given to recreational fishing. Although commercial fleets are willing and able to travel north to meet their quota, recreational anglers typically stay close to home, making the summer flounder’s migration evident. Under 2013 regulations, New York anglers faced relatively stringent size and catch limits and still surpassed their target by 13%. North Carolina anglers, who had much more lax limitations, came in under 67% of their target. “That’s just because the fish aren’t there,” says Kennedy.
“Overall,” says Kennedy, “this has resulted in a really significant problem in meeting recreational harvest limits.” Since 1995, annual recreational landings have ranged from 50% below to more than 100% above targets. The problem has been exacerbated by an inability to control participation and by fishing mortality.
While a reallocation of the long-standing state-by-state quotas may be the best solution to the problem, not everyone agrees on the underlying cause for the flounder’s new range—and thus, the right response. In the late 1980s, the summer flounder population was dismal due to overfishing. Since then, the summer flounder fishery has made a comeback. In 2011, the National Oceanic and Atmospheric Administration declared the fishery rebuilt.
Given that history, some speculate that the recent northward migration of summer flounder is not due to climate change, but is instead a consequence of rebuilding the fishery over the years. As the stock has rebuilt, the average age has increased, and older summer flounder like colder waters.
“We know there’s this correlation between temperature and stock, but we’re not delving into the mechanism behind it,” says Kennedy. “That’s really problematic.” In Kennedy’s opinion, states would be more likely to consider reallocating their quotas if they could be sure of the science behind the environmental change and natural resource responses.
“If we can get to a point where we have a really good understanding of the specific mechanisms and estimated projections of the movement and evolution of the stock over time,” says Kennedy, “our science could be used to bolster the case for reallocation.”
“Until you are able to make a strong case for the mechanism,” he adds, “you’re not going to be able to convince people to give up their allocation.”
A possible solution, says Kennedy, is adaptive resource management—a flexible decision-making process that can be adjusted in the face of uncertainties as outcomes from management actions and other events become better understood. This system requires a good understanding of both the natural physical science and social science and the ability to institutionally turn that information into actionable change.
Currently, the natural science team at the Mid-Atlantic Sea Grant project is mapping the distribution of summer flounder stock. Kennedy will then combine that information with his own findings on fishing effort and catch to make projections about how stock structure may change and how those changes may affect fishing mortality—in other words, how much fisheries in each state can catch.
The project “presents an opportunity to study some of the institutional factors that might need to change in order to move general fishery management to a more adaptive place,” says Kennedy. “I think it’s going to serve to be a good example and provide a lot of lessons for other fisheries, both in the Mid-Atlantic and around the country and the world.”
