Mary Beth Tooley said the figure is “draconian” and would put people out of work. “It’s just outrageous,” said Jeff Reichle, representing Lund’s Fisheries in Cape May, N.J. Science and Statistical Commit- tee scientist Patrick Sullivan said the determination of the allowable biological catch (ABC) was based on a “worrisome level of uncertainty” in the stock assessment. The SSC advised that the 90,000 mt figure should stand until the assessment is revised and the uncertainty is dealt with. The SSC said the assessment has a strong “retrospective pattern” in which estimates of stock size are sequentially revised downward as new data are added to the assessment. And they said that current fishing effort won’t maintain the current estimate of biomass. The SSC said the average retrospective inconsistency in the estimate of exploitable biomass is about 40 percent, or around 90,000 mt in 2010. The total catch of the Gulf of Maine/Georges Bank herring complex by U.S. and Canada in 2008 was 90,000 mt. Given the consistency in catch advice from these two approaches, the SSC’s recommendation was that the ABC should be 90,000 mt each year until the stock assessment is revised. According to a report of the Northeast Fisheries Science Center’s Retrospective Working Group, a retrospective pattern is a systematic inconsistency among a series of estimates of population size, or related assessment variables, based on increasing periods of data. The pattern of change in estimated values can have severe consequences for management of a stock, potentially resulting in depletion of a stock even though the assessments indicate the targets are being met. Retrospective patterns have been observed in some but not all of the stocks in New England, as well as other stocks around the world. The three main causes of retrospective patterns are changes in the level of catch accounted for in the assessment, changes in the natural mortality rate, or changes in the survey catchability. Catch is most often assumed to be underestimated, due to illegal or unreported landings or else due to underestimation of discards. “Survey catchability” is information regarding the trends in stock abundance and can come from fishery independent surveys, for example the NEFSC bottom trawl survey, or from fishery dependent catch per unit effort time series. A number of New England groundfish stocks have exhibited retrospective patterns which have typically persisted for many years, although there are cases when the direction of the pattern has changed suddenly (e.g. Georges Bank cod and summer flounder). The patterns have caused difficulty for the management of these stocks. “If retrospective patterns were merely an interesting statistical oddity,” the Retrospective Work- ing Group report says, “it is unlikely so many people would have spent so much time studying this topic, both within and outside this working group. However, there are severe implications for both managers and the stock itself when stock assessments exhibit strong retrospective patterns. Management advice will be biased and could lead to continued overfishing of the stock, inability to achieve rebuilding targets, and loss of potential yield. These problems have been demonstrated in a number of actual stocks, notably Georges Bank yellowtail flounder.” If stock size and recruitment rate are overestimated, the report says, this could result in the recommendation of the next year’s catch rate that is too high. The error can be compounded in subsequent years. Knowledge of the cause of the retrospective pattern is required in order to set management measures, the report says. Despite the retrospective pattern, overfishing has not occurred and biomass has remained relatively stable at a high biomass since the mid-1990s, according to the NEFMC’s Herring Plan Development Team (PDT). “The PDT concludes that the retrospective adjustment should provide adequate precaution for these scientific uncertainties,” a PDT memo says. Combined Canada/U.S. landings averaged 90,000 mt during 1978-1994. Landings increased during 1995-2001, averaging 133,000 mt, and peaking at 145,000 mt in 2001. Landings declined slightly during 2002-2005, and averaged 109,000 mt. Landings increased to 116,000 mt in 2006, then declined to 90,000 mt in 2008. During 1978-2005, the U.S. accounted for about 76 percent of the total landings, but during the most recent decade, this percentage increased to about 85 percent. Stock biomass increased steadily from about 111,600 mt in 1982 to almost 830,000 mt in 1997, fluctuated without trend since then, and was estimated to be 652,000 mt at the beginning of 2008. This is below the maximum sustainable yield of 670,600 mt. U.S. landings since 2005 have averaged 89,000 mt. During 1978-1982, U.S. landings were about equally split between the weir fisheries and purse seines. During 1983-1992, most U.S. landings were taken by purse seines, but subsequently single mid-water and paired mid-water trawling have dominated landings, with purse seining accounting for only about 10-15 percent of total U.S. landings during 2000-2005. Since 2005, purse seining has increased while pair and single midwater trawling has decreased with pair trawling accounting for 56 percent, single midwater trawling 12 percent and purse seine 26 percent. New provisions in the Magnuson- Steven’s Act provide that ecological factors must now be considered when setting specifications for the fishery. Among the ecological factors to be considered are impacts on forage fish stocks and predator-prey interactions. Retro- spective patterns, Sullivan said, are “really hard to try to understand and deal with.” Sullivan said it would be inadvisable to try to predict whether the pattern will go up or down. At the moment, he said, the pattern is going down. One is drawn to try to see a trend and then adjust for it, said Sullivan. “That’s a mistake,” Sullivan said. “Really what the retrospective pattern is telling you is there is something you don’t know about the fishery. If you did know it, then you’d correct it and then you wouldn’t have the retrospective pattern. We want to steer clear of using retrospective patterns to guess what changes are going on and use it to recognize that there’s something changing in this fishery and we don’t know what it is. That’s what happened with cod. Cod collapsed, and it hasn’t come back. Herring has a very similar pattern. – same direction, similar magnitude.” NEFMC members objected to taking a single year’s catch – 2008’s 90,000 mt – as an indicator for the future. A 90,000 mt ABC could result in a 50 percent reduction in catch in some areas, Tooley said. Pierce asked the SSC to consider a smaller buffer of 17 percent, as a figure that would reflect the assessment’s entire timespan and would be sufficient to account for scientific uncertainty. “I think it’s extremely precautious – too much so,” Pierce said of the 40 percent buffer. The NEFMC is scheduled to approve the annual catch limit for herring at its November meeting. If the SSC can’t meet on the question before then, the assumption is that the NEFMC would use the ABC of 90,000 mt. The SSC is not charged with considering the social or economic impacts of their recommendations. Sullivan was skeptical about reconsidering the numbers. He said there is no new information that might change the outcome. “I don’t see any additional information that would likely change what the SSC would consider,” Sullivan said. “I’m not sure it’s going to change anything.” Pierce said it was a question of interpretation. “It’s a reasonable request to make…especially in light of the fact that we are going to have a new benchmark assessment very soon and we’ll be able to set new quotas based on that benchmark assessment,” said Pierce. “But I’d like to have an industry still standing when we get that benchmark assessment, so that we can have something to manage.” Ronald Smolowitz, owner of Coonamessett Farm on Cape Cod and technical consultant to the Fairhaven, Mass.-based Fisheries Survival Fund, which includes more than 120 full-time Atlantic sea scallop fishing vessels from New England to North Carolina, said the ABC can be set by a peer-review panel instead of the SSC. Smolowitz asked that Maine, Massachusetts and New Hampshire put together a peer-review panel to come back to the NEFMC with an alternative ABC. “I think the 40 percent is grabbing at straws,” Reichle said. “There’s nothing in the resource condition to indicate a problem of this magnitude.” In the end, the NEFMC asked the SSC to revisit the size of the 40 percent buffer and to consider whether a buffer of about 17 percent would be sufficient to account for scientific uncertainty caused by retrospective patterns. |
