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data, contain acknowledged defects and/or are stale and outdated.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 (http://journal.nafo.int/40/moser/2-moser.pdf)
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 (http://www.miamiherald.com/2013/12/29/3840120/all-fishermen-dont-belong-in-the.html).
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.
And in the end, success is the only thing that matters.
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