On Georges Bank and in the Gulf of Maine, cod stocks have collapsed. A stock assessment update released in October 2015 found that the Gulf of Maine stock was experiencing a fishing mortality rate five times the sustainable level, while abundance had fallen to just 5% of the biomass target. The Georges Bank stock is in even more trouble. Abundance has fallen to a mere 1% of its biomass target, while fishing continues at a rate ten times greater than managers deem sustainable.
More than a decade ago, fisheries managers acknowledged that cod stocks were overfished and still subject to overfishing. In 2003, they adopted Amendment 13 to the Northeast Multispecies Fishery Management Plan (Amendment 13), which governs both stocks of cod, as their first serious effort to begin rebuilding the fishery. However, Amendment 13 failed to adequately address the problem, and subsequent efforts were equally ineffective.
Fishing in federal waters is governed by the Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens). Magnuson-Stevens includes a series of National Standards that fishery managers must adhere to when preparing fishery management plans.
National Standard One reads
“Conservation and management measures shall prevent overfishing while achieving, on a continuing basis, the optimum yield from each fishery for the United States fishing industry.”
When managers find a stock to be overfished, they must prepare a fishery management plan that includes a time period for rebuilding it, which time period shall
“be as short as possible…and not exceed 10 years, except in cases where the biology of the stock of fish, other environmental conditions, or management measures under an international agreement in which the United States participates dictates otherwise…”
Fisheries managers effectively ignored the 10-year rebuilding requirement when it was added to Magnuson-Stevens in 1996, but that changed after a federal appellate court decided the case of Natural Resources Defense Council v. Daley, and issued a decision which noted that
“Only in Superman Comics’ Bizarro World, where reality is turned upside down, could the [National Marine Fisheries] Service reasonably conclude that a measure that is at least four times as likely to fail as to succeed offers a ‘fairly high level of confidence’ [that it will prevent overfishing].”
The court went on to decide that, in order to comply with the mandates of Magnuson-Stevens, a fishery management plan must have the
“at-least-50% likelihood [of achieving its goals] required by statute and regulation.”
While Natural Resources Defense Council v. Daley established a minimum standard for fishery management plans, it also put fisheries managers on notice that they weren’t required to produce anything better than a plan that was as likely to fail as succeed.
Amendment 13 was such a plan. It stated that
“Rebuilding programs will be developed to rebuild most overfished stocks with a median (50 percent) probability [within 10 years]…
“The [New England Fishery Management] Council considered analyzing rebuilding trajectories with greater than a median (50 percent) probability of achieving the biomass targets…[T]he Council rejected this approach…The social and economic implications of the rebuilding programs are already substantial, and larger reductions in mortality would threaten the continued existence of the groundfish fishery…”
Adopting a mere 50% probability of success means that the plan will only succeed if nothing at all goes wrong, and that all of the unknowns will resolve themselves in the managers’ favor. Unfortunately, that rarely, if ever, occurs.
Thus, NMFS has adopted a set of guidelines intended to help managers comply with the mandates of National Standard One. The guidelines that the “acceptable biological catch” (ABC), which represents the maximum annual catch level for the relevant stock, should not be equal to the “overfishing limit” (OFL), because
“If the ABC were set equal to the OFL, then catching the ABC would result in a 50-percent chance of overfishing…In general, the higher degree of scientific uncertainty, the bigger difference there should be between OFL and ABC.”
Unfortunately, such guidelines do not have the force of law. The New England Fishery Management Council largely ignored them, and thus went awry.
In order to avoid “social and economic implications,” managers adopted harvest levels that did not adequately account for the scientific uncertainty inherent in the cod stock assessments.
They clung to high harvest levels even though the waters off New England, and the Gulf of Maine in particular, are warming faster than almost any marine region on Earth, and the impacts of that warming on cod remained largely unknown.
Even after the collapse of the Gulf of Maine stock was acknowledged in 2014, NMFS adopted a 386 metric ton (mt) annual catch limit for the 2015 fishing season, rather than the 200 mt limit that many believed necessary, because
“Based on the available projections, and analysis of the biological impacts of this action, [NMFS] determined that an ABC of 386 mt is sufficiently below the OFL to prevent overfishing, and will not jeopardize rebuilding…
“Although the Council could have considered, and recommended, an ABC lower than…386 mt, a lower ABC would not have mitigated economic impacts…”
So, twelve years after Amendment 13 failed to halt the cod’s decline, managers still discounted scientific uncertainty in order to minimize the short-term economic impacts of their actions.
The consequences of that approach were revealed in late October, when a paper published in Science described how warming ocean waters off New England were harming cod stocks in a manner that the stock assessment never considered.
The researchers found that warmer ocean temperatures reduced the number of cod that survived for more than one year. They also found that warmer water significantly increases the mortality of 4-year-old cod, which are just entering the spawning stock, and that those which survive weigh less than cod caught during periods of cooler water.
“The temperature-mortality relationship…means that in warm years, fewer fish are available for the fishery. Not accounting for this effect leads to quotas that are too high. The resulting fishing mortality rate was thus above the intended levels, contributing to overfishing even though catches were within prescribed limits. Socioeconomic pressures further compounded the overfishing…The socioeconomic adjustment coupled with the two warmest years in the record led to fishing mortality rates that were far above the levels needed to rebuild this stock…”
NMFS decision to ignore scientific uncertainty, in an effort to minimize economic impacts, had come back to haunt both the agency and the cod fishing industry, as stocks fell to unprecedented lows, requiring even greater harvest restrictions to be imposed.
It is probably appropriate to close with the researchers’ words.
“As climate change…reduces the productivity of some stocks, resource managers will be increasingly faced with trade-offs between the persistence of a species or population and the economic value of a fishery…Social-ecological systems that depend on steady state or are slow to recognize and adapt to environmental change are unlikely to meet their ecological and economic goals in a rapidly changing world.”
Thus, as oceanographic conditions continue to change, fisheries managers must incorporate a far greater allowance for scientific uncertainty into their decisions. If they fail to do so, their management plans will almost certainly fail, and protect neither fish populations nor the industries that depend upon their abundance to thrive.
Photo: “Atlantic cod under a shipwreck” courtesy of NOAA via Wikipedia