Sunday, January 26, 2014


In a perfect world, fisheries managers would have all of the scientific resources that they might possibly need to manage every species under their care.  Stock assessments would be free from uncertainty, and updated every few years.

Unfortunately, our world is not perfect.  Assessments for many species often lack needed data, contain acknowledged defects and/or are stale and outdated.  In the case of other species, no stock assessment exists at all.

Opponents of conservation efforts often point to such problems, and argue against regulations that, they contend, are not supported by “good science.”  At other times, they try to delay conservation initiatives, insisting that no regulations should be adopted until additional research is done.

Are they right?  Or can efforts to manage and conserve fish stocks succeed even when the available science is pretty sketchy?

Perhaps the best way to answer those questions is to leave theoretical arguments behind, and venture out into the real world, where we might be surprised to find that, when managing fisheries, accurate stock assessments, while nice, are not always needed.

Of all the species managed by the Mid-Atlantic Fisheries Management Council, none pose more of a challenge than black sea bass.

Fisheries managers consider black sea bass to be a “data-poor species,” and aspects of its biology are still being debated.  Lacking better information, biologists have established proxy figures that serve as the overfishing threshold and target stock size.

Black sea bass are protogynous hermaphrodites, which means that they begin life as females, but transform into males later on.  They form spawning aggregations in May and June (biologists believe), in which a dominant male attends (and probably defends) a harem of females.   Such dominant males tend to be very aggressive, and are normally among the first fish to be caught if anglers access an aggregation.  When that occurs, spawning is (thought to be) disrupted until the largest female transforms into a new dominant male, a process that (scientists think) occurs soon after the dominant male is removed.

All black sea bass north of Cape Hatteras, North Carolina are managed as a single stock, but that probably doesn’t represent reality.  In 2009, Joshua Moser and Gary Shepherd, of the Northeast Fisheries Science Center, published a paper ( suggesting that there may be three distinct subgroups of black sea bass which do not mix significantly during the summer, but do mix after migrating offshore during the winter.  No one knows—or has even publicly speculated about—whether the same regulations are appropriate for all three of the subgroups, or how mixing affects management.

Because of such uncertainty, the most recent stock assessment (December 2011) was unanimously rejected by a panel of independent fisheries experts.  In doing so, it issued a report which noted that “the Review Panel suggest that development of an effective model is likely to require a considerable investment of additional effort and will not be achieved in the short term.”

In other words, there’s still a lot of missing information, and it will be a long time before it is pulled together.

But does the lack of a valid stock assessment mean that the black sea bass stock couldn’t be adequately managed?

Far from it.  In 1997, just after the Sustainable Fisheries Act became law, the biomass of the black sea bass stock—that is, the combined weighed of all black sea bass swimming north of Cape Hatteras—was thought to be about 2,700 metric tons.  By 2010, when federal managers successfully rebuilt the stock, the biomass was estimated at more than 10,800 metric tons.

In 1996 (again, before SFA was adopted), the fishing mortality rate for black sea bass was an unsustainable 0.97 (nearly 65% of the fish were killed each year); by 2010, fishing mortality was reduced to 0.18 (about 16% of the fish removed).

Thus, without a good stock assessment and lacking a lot of pertinent science, fisheries managers still managed to end overfishing and bring harvest down to sustainable levels, while fully rebuilding a once-overfished stock.

That sort of success puts the lie to statements made by folks such as John Brownlee who, a few weeks ago, authored a guest editorial which appeared in the Miami Herald and attacked the federal fisheries management system (  
Brownlee’s editorial effectively set out the manifesto of the anglers’ rights groups who want to weaken the conservation provisions of the Magnuson Act.  With respect to science, he states

Catch limits based on actual science, rather than non-existent data.  Currently, catch limits are established for every fish population under management, even if there is no reason for concern about the health of a population. Science should lead the process of fishery management. A one-size-fits-all strategy is a recipe for disaster.

Like many of the statements in Brownlee’s editorial, it sounds good at first reading, but falls apart as soon as anyone stops to think about what it really says.

In our imperfect world, we are always going to lack the data needed to manage most species with anything approaching scientific certainty.  Federal managers are responsible for hundreds of separate stocks; state managers are responsible for many more.  It isn’t realistic to expect them to have either the human or the financial resources to produce frequent, peer-reviewed assessments for every stock.

And yet there is something inherently wrong with the idea of fishing a stock down, perhaps past some yet-undefined point of no return, just because biologists lack perfect data.

In a rational world, where perhaps Brownlee does not reside, it would make more sense to proceed with even greater care when data is lacking, to avoid inadvertently overfishing a vulnerable stock.

And if a population appears healthy—if there is no current reason for concern for its health—isn’t it sensible to put catch limits on now, before a problem arises, rather than having to play catch-up after that population declines?  Haven’t we learned at least that much from our past mistakes?

Isn’t it better for managers to do the best they can with whatever tools and information that they have at hand, even if it is far from perfect, rather than sit on their hands, do nothing and possibly put a stock at risk?  Isn’t it better to be a little cautious—maybe even a little overcautious—in the face of uncertainty, rather than to accidentally cause a population collapse?

Some people would clearly say no.  They would use a lack of data, of peer-reviewed assessments and of unassailable science (if there is such a thing) to stall any efforts to conserve and manage a stock, and so perpetuate their ability to harvest—and maybe to overharvest—such stock.

For if you try hard enough, you can always come up with a good reason to do the wrong thing.

But it's better to do the right thing.  In the face of uncertainty, it is better to manage a stock like black sea bass, with imperfect science, no stock assessment, no population model and no carefully derived reference—but with a measure of caution—and still end up with no overfishing and a fully recovered stock.

The black sea bass shows us that without much science, managers can still succeed.

And in the end, success is the only thing that matters.

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