Wednesday, April 25, 2012

Fisheries Roundtable discussion: the Gulf of Maine cod "crisis"

It's enough to make your head spin. Maximum sustainable yield, fishing mortality rate, spawning stock biomass -- these are terms fisheries managers are intimately aware of, yet they seem so esoteric that it's difficult for the layperson to wade into the discussion. But the reality is this: local fishermen could be faced with drastic cuts in the number of cod they're allowed to catch (total allowable catch, or TAC), unless an act of Congress is passed. No, really: it would take an amendment of the Magnuson-Stevens Act (MSA), originally passed in 1976, reauthorized in 1996 and 2006, to soften the potential impacts to fishing communities throughout New England.

First, let's talk about background issues that are influencing the current management "crisis" in New England. The basis of all this, the MSA, has good intentions -- it is meant to preserve healthy populations of fish species in our oceans. From an ecological perspective, the MSA is a home-run on paper. The reality of its associated rules -- and thus impacts on fishermen's livelihoods -- gets a bit complicated.

Stock assessments help fisheries managers keep tabs on various stocks to see if they are considered overfished (i.e., is the population already too low?) and if overfishing is occurring (i.e., are fishermen harvesting too many right now to maintain healthy stock levels into the future?). A fish stock can be considered overfished but not be exposed to overfishing, meaning that although the population is very low, the fishing rate is also set low to prevent further impacts to the fishery.

So when a fish stock is considered overfished, new measures need to be put in place to help rebuild the fish populations. That means cuts in the number of fish that fishermen are allowed to catch (TAC). All these decisions are based on assessments and surveys of the current fish populations. Stock assessment computer models provide estimates of the number of fish and their biomass using a complicated algorithm that takes into account factors like how many fish die naturally each year (natural mortality), how many fish are captured by fishermen (fishing mortality), the number of young fish that will soon be large enough to capture in nets (recruitment), and various other indices.

Gulf of Maine cod and haddock experienced a population decline in the mid-1990s, and so the fishery was shut down for a number of years. Once it was reopened, New England fishermen worked hard to stick to the laws and help the population rebuild. So it was with a feeling of pride that scientists at the Groundfish Assessment Review Meeting (GARM III) in 2008 announced that the cod stock was rebuilding well, with an estimated 33,000 metric tonnes (mt) of cod in the Gulf of Maine. Data presented at the GARM also indicated there was a strong 2005 cod year class. These assumptions were based on computer model estimates and spring trawl surveys.

So fishery managers set the TAC limits accordingly. Fishermen followed these limits, and in fact only caught 84% of the limit in 2011 -- the first year of the catch share quota system, in which they were concerned about the staggering fines associated with overharvesting.

Then came news late last fall based on the 2011 stock assessment: the previous assessment in 2008 had dramatically overestimated the spawning stock biomass (SSB) -- it was closer to 14,000 mt than 33,000 mt -- and the 2005 year class was not nearly as strong as they thought. According to the 2011 stock assessment, the cod stock was considered overfished and overfishing was still occurring, requiring an end to the overfishing in two years and setting up a strict 10-year rebuilding plan. But the MSA doesn't include any protective measures for fishing communities. A wave of panic set in among the fishing industry, spurred by media headlines.

The most recent Fisheries Roundtable discussion, held on April 19th from 6-8 pm at the Portsmouth Public Library, focused on this issue. The goals of the meeting were to provide information about stock assessment and modeling, outline the current cod crisis, provide examples of alternatives to the current management system and to provide a forum for discussion about solutions to move forward. To meet these, goals, four speakers were invited to weigh in with their perspectives of the two very different stock assessments and their estimates.

Paul Rago, chief scientist of the Population Dynamics Branch of the Northeast Fisheries Science Center, said there is no "smoking gun" associated with the differences in populations estimates, such as an increase in cod predation, decreased forage fish populations, climate change impacts, unrecorded discards or landings.

Dr. Paul Rago, of the Notheast Fisheries Science Center

He said there will be a new Gulf of Maine stock assessment conducted this year, but no matter what they find, the bottom line is that cod populations won't be rebuilt by the 2014 deadline.

The 2011 assessment was developed with input from fishermen and scientists and was a peer-reviewed process. "These reviewers were not by any means wet behind the ears," Rago said. The assessment is considered to be an improvement due to more detailed meetings with the fishing industry, a complete review of historical data, and better accounting of total fish removals. This newer model is better able to deal with uncertainty in the data and provide what he says is a more accurate estimate.

The next speaker, David Goethel, a groundfisherman based out of Hampton, N.H. on the F/V Ellen Diane, said that despite being a member of the New England Fisheries Management Council -- the organization responsible for setting TAC to adhere to the MSA -- he spoke to the audience from a fisherman's perspective. "I feel the Council is between a rock and a hard place, with the rock being the MSA and the hard place being the devastation to fishing communities should these extreme (fishing) cuts take place," he said at the beginning of the presentation. "So we have two choices: Congress can amend the act, or we live with the cuts."

Captain David Goethel, FV Ellen-Diane, Hampton, NH

Goethel is quick to defend the scientists too, claiming that they have insufficient time and resources to fully investigate all the scientific issues involved in stock assessments to make accurate estimates.

"Stock assessment scientists are being rushed to set (fishing) limits too quickly, so we don't have the time to do things the right way," he said. He believes incorporating natural history aspects of the fishery --- such as fish behavior, bottom water temperatures, food availability and the like -- is critical to obtaining more accurate population estimates.

"We have become overly mathematic at the expense of actually studying the fishery," Goethel said. "Model estimates should be tested against common sense."

Goethel made an interesting case in comparing fish stock assessment models to weather models. Fisheries managers use only one model estimate on which they base their TAC decisions, and their decision based on the estimate is fixed for a period of time in management measures that fishermen must follow. Conversely, weather models predict numerous potential tracks where a storm could go, there is discussion about the options on how far the storm might veer from that track (called "uncertainty" in scientific terms), and the estimate evolves over time. If we applied the fishery model to weather, we might predict that a storm will head toward Nova Scotia when it ends up hitting downtown Manhattan instead, Goethel suggested.

Steve Cadrin, director for the NOAA/UMass Cooperative Marine Education and Research Program at the UMass/Dartmouth School for Marine Science and Technology, put it a bit more simply: our science isn't perfect, but it's the best we have. However, he suggested that we should develop a management approach that acknowledges the limitations of that science that is currently available. He emphasized that the cod "crisis" isn't as much a population crisis as it is a management crisis.

 Dr. Steve Cadrin, UMass Dartmouth

"The current perception is that the 2008 assessment was wrong," Cadrin said. "This means that the population is not precipitously declining, but that it was just never that large to begin with."

"The crisis is not the result of irresponsible management, excessive fishing or a decline in the stock," he explained. "It results from the scientific uncertainty, infrequent stock assessments, an abrupt change in perception, a rapid stock rebuilding schedule and a poorly estimated rebuilding target."

While stock assessments are definitely useful for estimating stock status (overfished, overfishing) they are less well-suited for establishing catch limits -- which happens to be their current use. Cadrin suggested evaluating the performance of other types of models, perhaps not unlike taking the car for a test drive before you buy it.

"The management system requires accurate projections and estimates of uncertainty," he added. "We need a hurricane track we can trust, and an area of uncertainty around that we can also trust."

Tom Nies, the senior fishery analyst for the New England Fishery Management Council, said the upcoming couple of years will bring a lot of workshops and discussions about how to improve stock estimates. Models would likely benefit from the inclusion of data collected during tagging studies and cod genetic research.

 Tom Nies, New England Fisheries Management Council

Although fishermen caught 11,000 mt of cod in 2010, this year the catch will likely be set around 6,700 mt and 2013 could be as low as 1,100 mt, he said.

Haddock won't be an alternative to catching cod, Nies warned, as the low haddock stocks in the Gulf of Maine will also face a 60-70% cut in TAC.

"It looks pretty bleak for the next couple of years, and the Council is wrestling with this," Nies said.

All four speakers offered a panel discussion to answer audience questions after their presentations concluded. There was some exchange regarding whether or not predators like seals or spiny dogfish might be impacting cod populations, although Rago said there is very little evidence to suggest that is part of the problem. However, he acknowledged that natural mortality is difficult to assess.

Most of the speakers felt that setting a rebuilding target and deadline was causing a "roller coaster" effect of one year feeling confident to harvest a species and the next scrambling to quickly rebuild the population. Cadrin and Goethel suggested instead to set a goal of realizing some measure of rebuilding each year, making slow and steady progress. Goethel also suggested moving towards multi-species management might help, as ecosystems are complicated and a change in one species will likely result in impacts on other species anyway.

Regardless of their affiliation, all four speakers reiterated the fact that no one will benefit if the fishery collapses, so everyone wants to make sure a solution is found to keep things moving forward on a positive track.

For more information about basic stock assessment, please check out the N.H. Sea Grant Guide to Stock Assessment:

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