Have Your Hake and Eat It Too
Last year, NOAA scientists and West Coast fishermen collaborated to reduce uncertainty in the Pacific hake fishery, improving near-term outlook for fishermen while protecting long-term availability of the fish.
|The graph above represents estimated female spawning biomass of Pacific hake from the late 1960s to the present, with blue shaded area representing uncertainty. Sharp upturns are big year classes from 1980, 1984, 1999, 2008, and 2010 that show up in spawning biomass a few years later. Reduced uncertainty in the 1990s is due to better data collection and the introduction of acoustic surveys.|
All fish populations are unpredictable, and each is unpredictable in its own way. Pacific hake are an especially volatile species whose natural ups and downs often take us by surprise. Also known as Pacific whiting, this species supports the nation’s fifth largest commercial catch by volume. For the West Coast communities that depend on hake, uncertainty about which direction the population is heading has always been a problem.
For the past few years there’s been even more uncertainty about this fishery than usual. The stock assessment conducted in 2011 produced an unexpectedly low biomass estimate, which would mean lower catch targets for at least a few years. At the same time, fishermen were seeing indications that the hake population was about to boom. If they were right, then catch targets could go up rather than down. Amid these conflicting signals, there was much uncertainty about which way was the population truly headed.
The best way to reduce the uncertainty around the population trend for Pacific hake was to survey the population again. But fish surveys are expensive, and NOAA surveys hake only every other year. The next survey wasn’t scheduled until the summer of 2013.
By working together, NOAA Fisheries, the Department of Fisheries and Oceans Canada, and the fishing industry managed to run an off-year hake survey in the summer of 2012. They did this by piggybacking the hake survey onto an already scheduled sardine survey. The industry provided a catcher boat and crew that sailed alongside the NOAA research vessel to manage the extra workload. And NOAA scientists overcame the technical hurdles to simultaneously surveying both sardine and hake, which live at different depths.
The results from that survey are in. So is the hake population falling? Or is it about to explode? And will fishermen see their catch targets go up as a result of this new data?
Managing the Risk That Arises Out of Uncertainty
Before we get to the numbers, it’s worth considering why reducing uncertainty can allow catch targets to go up. We want fishermen to take as many fish as possible today while leaving a viable population in the water for tomorrow. To do that, we need to know how many fish are out there. But as the story of Pacific hake demonstrates, our estimates of fish abundance will always involve a degree of uncertainty.
This uncertainty creates risk. If we overestimate the biomass of the population, and fishery managers set too high a catch target based on that estimate, then we will overfish the stock. Because hake tend to bide their time, waiting for just the right combination of environmental conditions before producing a big year class, it can be a long time before the population recovers. Until it does, fishermen will be stuck with lower catch limits and the resulting economic consequences.
To help reduce this risk, when NOAA Fisheries publishes a biomass estimate for a fish stock, we also specify the degree of uncertainty around that estimate. This allows the local fishery managers who set the catch target to adjust for uncertainty. When uncertainty is high, they can bring the catch targets down as a precaution. On the other hand, when uncertainty is low, they can confidently set catch targets closer to the biological maximum without increasing their risk.
Fishery managers must choose how much risk to assume, and in the media this process is often portrayed as a contest between overly cautious scientists and fishermen who want to catch as much as possible. But in fact, both are invested in the long-term sustainability of fish populations. And as the case of the off-year hake survey demonstrates, managing risk and uncertainty requires collaboration between scientists and the industry.
Mike Okoniewski, an operations manager for Pacific Seafood, was a driving force behind the collaborative hake survey. "The scientists are more academic,” he said, “and we're more practical as we do our jobs
on the ocean. But we've both got skin in the game, and there's
a lot to be gained by bringing these two sides together."
And the Survey Says…
The numbers are now in, and it looks like the low 2011 biomass estimate was mostly accurate. It appeared low, however, in part because of an overly high estimate in 2009. It also didn’t include the 2010 year class because the survey technology can’t reliably register fish that young. NOAA scientists are continuing to develop cutting edge sonar technology that will allow them to estimate the strength of incoming year classes as one year olds.
At the same time, hake fishermen were right in thinking that the population was about to take off. In the off-year hake survey, the two-year-olds from the 2010 year class accounted for more than half the total biomass of the population. Since that year class has been surveyed only one so far, there is still a lot of uncertainty around that estimate. But the uncertainty is about whether the 2010 year class is big, or very big. Either way, it looks like fishermen will be living off it for years to come.
The catch target for Pacific hake this year will be 365,112 metric tons, shared between the U.S. and Canada. That’s a 45 percent increase over the year before, which is about where the target likely would have stayed without the extra survey.
NOAA and the fishing industry hope that Pacific hake will be surveyed annually from now on, though it’s unclear if the necessary funding will be available.