As the oceans warm, fish populations are on the move. A new online database that tracks their movements should help fishermen and fishery managers to adapt
[dropcap]F[/dropcap]ew people see the effects of climate change as clearly as fishermen. As the climate changes and the oceans warm, fish are moving in search of cooler water, and this can have a big effect on fishermen’s livelihoods. For some, the evidence of climate change turns up in the net, such as when they catch longfin squid in the Gulf of Maine, far north of the usual range for that species. For others, the evidence is in what they’re not catching. Lobstermen in the Long Island Sound, for instance, have had little to catch since the valuable species that once supported them headed up the coast. Winter flounder, silver hake, and black sea bass have all shifted north as well.
Black sea bass is one of many species that are moving as the oceans warm. This graph shows how the center of the species’ distribution has changed latitude over four decades. It is moving North.
These are just a few examples from the East Coast, but a study released last year that looked at more than 350 species from all over North America found that many are moving, and that their movements closely track changing ocean temperatures.
“We found that all over North America, marine fish and invertebrates are shifting their distributions quite rapidly,” said Malin Pinsky, a biologist at Rutgers University and the lead author of the study, which compiled data from more than 40 years of surveys conducted by scientists at NOAA Fisheries, Canada’s Department of Fisheries and Oceans, and other organizations. Those surveys were designed to produce estimates of fish abundance that managers use when setting catch limits.
But even though few people were thinking about climate change when those surveys were originally designed, they turned out to be a treasure trove of data for tracking the effects of a changing climate. “These data show where marine fish and invertebrates have been, and where they’ve moved, over the last several decades,” Pinsky said.
In the year since that study was published, Pinsky, in collaboration with NOAA Fisheries, has built a website called OceanAdapt that makes that trove of data, which had been scattered and difficult to access, easily available to the public. Users can search and download data on the geographic and depth ranges of more than 650 species of fish and invertebrates and track how those distributions have changed over time. This will be a valuable tool for the fishermen, fishery managers, and scientists who are grappling with the challenge of adapting to a changing climate.
When Fish Cross State Boundaries
Black sea bass are important to both recreational and commercial fishermen on the East Coast, and each state gets a fixed share of the total catch. That catch was divvied up based on where black sea bass were in the late 1980s and early 1990s. At that time, the fish were most abundant off North Carolina, so that state got the largest share of the catch. Since then black sea bass have moved, but the regulations haven’t caught up. Today, New England fishermen are catching black sea bass as far north as the Gulf of Maine. Meanwhile, North Carolina fishermen often have to motor far north to fill their quota, with the extra fuel costs eating into their profits.
“Our fisheries regulations are built around the idea that fish distributions don’t change very much. When they do, that makes things complicated for fishermen and for managers trying to maintain a sustainable fishery,” Pinsky said.
But changing fishery regulations to reflect today’s conditions won’t be easy, in part because any redistribution will inevitably leave some states with less than their historical share. What’s more, fishery regulations exist to prevent overfishing, and in that respect they have worked—36 stocks have been rebuilt in U.S. waters since 2000. For that track record to continue, any changes to fishery regulations must be made with great care.
“How do you make the regulations effective and yet flexible?” asked Pinsky. “That’s one of the big challenges ahead.”
[information]
Source NOAA The OceanAdapt Website / By Rich Press, NOAA Fisheries Science Writer | Posted: December 9, 2014 Follow Rich on Twitter: @Rich_NOAAFish
[/information]
