Thursday, July 30, 2015
THE NUMBERS' STORY
It’s one of the truisms of fisheries management.
Any time that managers make a decision that someone doesn’t like, before the ink is dry on the press release, someone will pop up to cry “The numbers are bad.”
It doesn’t really matter which species in involved, or how good the science that supports managers’ decisions might be. Someone is going to challenge the numbers.
Consider the recent debate at the Atlantic States Marine Fisheries Commission over striped bass conservation. It occurred after a benchmark stock assessment determined that the population would almost certainly become overfished by 2015, after anglers from Maine to North Carolina were reporting declining numbers of fish and demanding that something be done. Even so, some members of ASMFC’s Striped Bass Management Board denied the existence of any problem, and sought to cast doubt upon the stock assessment. Tom Fote, thegovernor’s appointee from New Jersey, was typical of such folks, saying
“It seems I’ve been here over the years doing the same thing. We have been looking at some figures for a period of time and then decided we’re going to do a drastic cut. Two years later they’re finding out that we didn’t need the drastic cuts and had to change the regulations in New Jersey again…
“In my estimation, we’ve been where the sky is falling, and a whole bunch of people yammering…Whether fish come inshore or not depends on water temperature and with the bait inshore a lot of times, and that is what it affects especially when we keep the [Exclusive Economic Zone] closed…
“…People have been pushing for closing this or doing something. The people that basically send the e-mails are the people that want to do that. The people that are out fishing a lot of times, which is a majority of the fishermen I go around and talk to, they’re not ready to jump through this type of hoop…”
All of the data in the stock assessment, supported by what the “people yammering” note about the striped bass population were, to their eyes, invalid. Conservation measures weren’t required, they told us, because “two years later” the water temperatures would improve, or forage fish would move inshore, and all would be well with the world.
Of course, if they had gotten their way, and things were worse a couple years down the road, they’d find other reasons to protest…
But “flawed data” or, as some like to exclaim, “fatally flawed data,” is still the typical response to conservation efforts.
Back in the fall of 2009, the Recreational Fishing Alliance announced a lawsuit brought against federal fisheries managers claiming—you guessed it—“fatally flawed data” that constrained harvest in the recreational black sea bass fishery. In that pressrelease, the RFA warned anglers
“What’s worse is that there seems to be no end in sight to the [Marine Recreational Fishing Statistics Survey’s] assault. Today it’s the complete shutdown [after the recreational allocation had allegedly been landed] of a healthy sea bass fishery. Next, we can expect an impact on the summer flounder limits for 2010, and scup soon after that. Could striped bass be next? How about [tautog]? If “fatally flawed” data has not impacted your favorite fishery, rest assured that it will happen soon enough if we don’t take a stand today. Where does it end if we allow the federal government to continue to use a broken system to deny recreational anglers access to healthy fisheries?”
While just about everyone will admit that the MRFSS data used to close the black sea bass fishery in 2009 was far from perfect, the judge hearing the case noted that federal regulators were improving their data-gathering process, and decided that plaintiffs’ claim that data problems would cause fishery closures to recur wouldn’t fly, saying that
“Plaintiffs provide no support for [a]…reasonable expectation that an emergency closure will recur.”
But still, folks like to criticize the data, largely because they don’t understand how it works.
Anyone wanting to really understand the system must first accept the fact that every number used in a stock assessment, harvest assessment or other management calculation includes some degree of error.
In some cases, such as commercial landings estimates, the error levels are pretty small, because vessel trip reports can be cross-checked against fish house weighout slips. But even that sort of ground-truthed process isn’t perfect, as was recently demonstrated when commercial fishermen and fish houses here in New Yorkcolluded to misreport hundreds of thousands of pounds of summer flounder landed pursuant to the Research Set-Aside program.
In other cases, such as when data from the late and unlamented MRFSS program was applied to a seldom-caught species in a single state, the data could be so imprecise as to be unusable, and it was such situations that were often used by critics to impeach the MRFSS data. Yet when MRFSS was applied on a coastwide basis to often-encountered species, the estimates really were pretty good.
At any rate, the number represented by such calculations—whether an estimate of biomass, recreational landings or the level of harvest that will produce optimum yield—doesn’t mean that, for example, exactly 1,342,906 striped bass were caught in a given state in any particular year. Instead, that number represents what is called a “point estimate;” the actual number of fish caught is almost certainly higher or lower—perhaps much higher or lower, depending on the quality of the data—than the point estimate itself.
And that’s the first thing that the “faulty data” folks don’t understand. Because when they scream “Bad numbers!!!” they might really be right, but even if the point estimate is well off the mark, there is no way of knowing where the error lies.
People trying to fight conservation measures consistently try to argue that, because the data is imprecise, managers should assume that harvest estimates are too high, biomass estimates are too low and the number of fish that can be safely removed from a population is higher than the stock assessment suggests. In fact, a proposalto increase black sea bass landings, introduced at last May’s meeting of theMid-Atlantic Fisheries Management Council, actually included all three of those assumptions.
Unfortunately for such people, it is as likely as not that the opposite is true, and that harvest was underestimated, the biomass is smaller than believed and sustainable harvest requires that fewer fish be taken out of the population.
Thus, if the data really is bad (and black sea bass are recognized as a “data-poor species”) the prudent course isn’t to assume that the stock can sustain higher harvests, but rather to exercise a greater degree of caution and set harvest levels well below what the point estimate suggests, to avoid accidentally crashing the stock.
Of course, that’s exactly the opposite of what the “Flawed data!!” folks are trying to do.
The numbers are telling their story, but it’s not one that such folks want to hear.