Mega Millions, Fishery-Style

Apr 5, 2012 by  | Bio |  Leave a Comment

This piece was originally published on TalkingFish.org.

Federal fishery managers rolled the dice on the New England cod fishery on Monday, once again. It is hard to escape the premonition that they fell well short of their responsibility. We think catch levels were set too high, too little was done to reduce the growing cod catches of recreational fishermen, and nothing was done to balance fishermen’s economic and social pain by directing the small allocation of Gulf of Maine cod toward coastal fishing boats.

The decision of the National Marine Fisheries Service (NMFS) to accept the New England Fishery Management Council’s quota recommendation had little to do with precautionary principles and much to do with politics.

Atlantic cod (photo credit: NOAA).

The 2011 Gulf of Maine cod assessment, which has a broad consensus in the science community, concluded that the fishing levels for the last three years had been set perhaps five times as high as they should have been. A large percentage, sometimes bordering on almost 90% of the spawning cod, has been caught each year in recent times. With few adults older than ten years old in a population that should include significant numbers of highly-reproductive twenty-something-year old fish, the spawning populations are buoyed by little more than the individual year-classes of new maturing fish, year-by-year. The risks of a Gulf of Maine cod train wreck may well be much higher than this decision assumes.

The one thing that is known with certainty about past cod assessments is that they have consistently overestimated the spawning biomass and underestimated the amount of human and natural mortality that is happening in the real world. The scientists are not counting all the fish that are actually being killed each year. In the fisheries modeling world, this sort of systematic model error is called a retrospective pattern. The new assessment, just like prior assessments, is still based on a model exhibiting a retrospective pattern.

What this means in simple language is that while the managers think their new catch levels pose a 30% risk of bringing spawning fish populations down to new historic lows, the real risk is almost guaranteed to be higher – and only time will tell how much higher.  The scientists’ best estimate is that Gulf of Maine cod spawning stock biomass (the amount of the stock that is capable of reproducing) is roughly 11,868 metric tons (mt). By setting new 2012 catch limits at 6,700mt, NMFS and the Council expect that 56% of this spawning population will be caught in the fishing year. But this 11,868mt estimate is just one in a range of estimates; the actual spawning stock biomass could be lower or higher. In fact, the approved 6,700mt catch level could remove anywhere from 41% and 71% of the entire spawning population with equal confidence. Killing two-thirds of the spawners in a population that is already decimated is not rational.

And it is critical to remember that these are just best scientific estimates. The unforeseen cod collapse in Atlantic Canada in the 1990s that has lasted many decades now produced one irrefutable fact: even the smartest people in the room can’t fully understand or predict, let alone control, the biology of a situation. We should be mindful of that if we are to avoid our own cod collapse.

On the brighter side of the NMFS interim cod action, the managers didn’t open up any of the areas that are currently closed to fishing in order to protect important fish habitat and help species rebuild. That would have done little to help Gulf of Maine cod fishermen and much to undermine other rebuilding stocks that likely benefit from these closed areas. Significantly more analysis is needed before that action should be considered.

We are also encouraged to see that additional cod assessments and analysis will be done later this year. There may also be new assessment tools—specifically, the new low frequency sonar technologies developed by MIT and Northeastern—that might finally allow scientists to “see” the fish under the water and get a better real-time estimate of what the total populations of cod might be. All this work is of the highest priority. It would be a great relief if the latest assessment turned out to be overly pessimistic.

The power of denial and the risk of significant bias in these efforts, however, cannot be overstated.  The new analysis must be done right. With so much political pressure, so many fishermen in serious economic straits already, and so many scientists heading into the effort hopeful that a new look at the cod populations might produce a better result, the tendency to skew the inquiry will be practically unavoidable. With the long-term health of Atlantic cod in New England in the balance, however, the integrity of the scientific process must be protected.

There is no way to completely reduce the risks in a fishery, no perfect fishery. Nonetheless, we had started to hope that the New England managers were getting more risk-averse and more focused on realizing the important goal of managing this pivotal fishery out of its persistent crisis state. We hoped that they were becoming more mindful of the bad distributional effects of some of their management rules on the smaller coastal day boats. This latest cod decision negates optimism. It treated that long-term better and fairer future like some game of chance with such long odds that it wasn’t even worth playing.

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