Fishery management traditionally has focused on fishing pressure, the removal of animals from a population with nets, lines and traps, as the only statistic worth using in the regulatory equation.
The rationale is simple, at least in theory: If the landings in a fishery drop, it’s assumed that the population has declined.
Everything else that might change a fish stock – all the environmental, ecological or climatic variables that are virtually impossible to quantify with any accuracy – have been addressed as statistical constants in fish-population models.
But climate change and its rapid effect on fisheries are forcing scientists and policymakers to rethink the traditional management approach. Suddenly, every fixed point in the equation has to be reconsidered as a network of moving parts.
“We’re feeling pressure from a lot of people to get out in front of climate change,” said Richard Seagraves, senior staff scientist at the Mid-Atlantic Fishery Management Council, the federal regulatory body responsible for many of Rhode Island’s most important fish stocks. “We’re all asking ourselves, how does climate change impact the way we think about fish stocks? Whatever the answer, it’s going to be a huge undertaking.”
That re-examination has opened the doors for a new way of looking at fishery management that goes beyond fishing effort. Officials now recognize that predator and prey relationships can alter a fish stock: Seals, dogfish and sea bass can eat an enormous amount of squid, cod, lobster; a change in surface or bottom temperature can alter a fish stock by making the fish shift to more favorable habitats; and bycatch on fishing vessels, the discarding that happens at sea, often without proper documentation, can alter a stock by not accounting for animals being removed.
Every decision made in fisheries management gets run through a statistical model. Fishery policy is hungry for data, and its appetite will only increase as scientists, fishermen and managers try to understand and model the complex, interwoven relationships of the fishing industry and the marine environment, not as separate things but together.
Climate change scientists have their own models, but many are designed to identify patterns or generate predictions on a huge scale. For fishery-management purposes, the scale is just too large, way beyond the local concerns about where fish are caught, eaten, where fish decide to swim away, or head for new ground, says John Manderson, a fishery ecologist with the National Marine Fisheries Service.