Fish have traditionally been managed on a single-species
basis. That is, biologists calculate a
target level of abundance for each species, along with a lower threshold
biomass that is used to determine whether a stock is or is not overfished.
To maintain a stock at its target level, or to rebuild it if
abundance has fallen too far, biologists also calculate a target fishing
mortality rate, and a threshold rate that, if exceeded, warns that overfishing
is taking place.
Such calculations are
made without reference to any other species that shares the managed stock’s
environment, except to the extent that a lack of forage fish, or an abundance
of predators and competing species, might impact that part of the overall
mortality rate not attributable to fishing.
On the whole, single-species management has worked pretty
well, although it
may not be adequate to calculate the number of forage fish, such as Atlantic
menhaden, that should be left in the sea to provide food for predatory fish,
birds and marine mammals. Even so, a
number of biologists have suggested that it is time to move on from
single-species management to a more holistic approach generally referred to as “ecosystem
management” although, given how many different factors impact any given
ecosystem, that title suggests a more comprehensive management program will
probably ever be practical.
“The current U.S. fisheries management system regulates
fishing on individual populations or groups of similar populations. Although improvements to the law have helped
to end overfishing on many species and to rebuild a number of depleted
populations, they do not address the bigger picture. Each fish is a link in overlapping food
chains that form an interconnected food web of places, plants, and
animals. Ignoring these connections can
lead to serious consequences and cause dramatic shifts in the health of the
ocean.”
Recently, a number of similar arguments have been made by
various marine conservation advocacy groups.
Yet, even though ecosystem management has been getting a lot
more attention in recent years, the concept is nothing new. The Sustainable Fisheries Act of 1996
mandated the creation of an Ecosystem Principles Advisory Panel, which
completed its report to
Congress, entitled “Ecosystem-based Fishery Management,” late in 1998. That
report noted that
“Seeking solutions to reverse the decline of New England’s
fisheries in 1871, Congress created the U.S. Commission of Fish and
Fisheries. The first appointed Commissioner,
Spencer Baird, initiated marine ecological studies as one of his first
priorities. According to Baird, our
understanding of fish ‘…would not be complete without a thorough knowledge of
their associates in the sea, especially of such as prey upon them or constitute
their food…’ [emphasis added]”
Thus, it’s clear that neither the concept of ecosystem
management nor the reality of troubled New England fisheries are recent developments.
However, there is a big difference between talking about
ecosystem management and putting ecosystem-based programs into practice. When I sat on the Mid-Atlantic Fishery
Management Council from 2002-2005, I was asked to become the first Chair of the Council’s newly-created Ecosystem
Management Committee (since renamed the Ecosystem and Ocean Planning Committee). A dozen years would pass before the Council
would approve its “Ecosystem
Approach to Fisheries Management Guidance Document,” which was just posted
to the Council website earlier this month.
So progress in this area doesn’t exactly progress with
lightning speed.
One of the reasons for that is that people just don’t agree
on precisely what “ecosystem management” means.
The Mid-Atlantic Council’s Guidance Document states that
“An ecosystem approach to fisheries management recognizes the
biological, economic, social, and physical interactions among the components of
ecosystems and attempts to manage fisheries to achieve optimum yield taking
those interactions into account.”
That’s a very broad definition, certainly larger than the
Pew position paper’s concentration on “overlapping food chains that create an
interconnected food web of places, plants, and animals,” or Fish and Fisheries
Commissioner Baird’s concerns with managed species’ prey and predators. Once economic and social factors are
considered, they can become wild cards that upset any emphasis on biological
relationships.
The Guidance Document eases those concerns by stating that it
is focusing on four issues primarily linked to biological/oceanographic
considerations, including
“1. Forage/low
trophic level species considerations;
2. Incorporation of
ecosystem level habitat conservation and management objectives in the current
management process;
3. Effects of systematic
changes in oceanographic conditions on abundance and distribution of fish
stocks and ramifications for existing management approaches/programs; and
4. Interactions (species,
fleet, habitat, and climate) and their effects on sustainable harvest policy
and achievement of [optimum yield],”
with a footnote indicating that
“Social and economic considerations were integrated
throughout the analysis of the four topic areas.”
That’s important, because there is a very thin line between “ecosystem
management,” that takes a holistic approach to management by striving to
maintain sustainably-harvested fish stocks within an intact ecosystem, and by
adopting management measures to changing ecosystem conditions, and “ecosystem
engineering” which makes an effort to maximize social and economic benefits by reducing the abundance of organisms deemed “less
desirable” or “less valuable” while artificially increasing the abundance of
those that, for one reason or another, are more valued, and change the natural
structure of the ecosystem along the way.
Fishermen tend to confuse the two concepts. When I sat on the Mid-Atlantic Council, I
remember hearing comments from both Council members and the public to the
effect that the Council shouldn’t try to manage spiny dogfish, because they
only take up space and resources in the ocean that could better be utilized by
more valuable species.
And whatever the species being managed, there is always
someone willing to argue either 1) fishermen aren’t the cause of a species’
decline; the real problem is that they’re being eaten by something else (which should thus be killed off
in greater numbers), or 2) restrictions on the harvest of a particular species
should be relaxed, because “they’re eating everything in the ocean.”
Comments of the latter sort can devolve to
the level reached by one
of New York’s representatives to the Atlantic States Marine Fisheries
Commission’s Summer Flounder, Scup and Black Sea Bass Advisory Panel, who said—with
a straight face—that
“All those scup are eating lobster roe, small crabs,
shellfish, and baby flounder…When one species grows so much, it’s going to wipe
out some other species…Sea bass and scup are growing enormously and need to be
contained to a reasonable amount. You
can’t allow one species to devour everything else…
“The biomass for sea bass is so much higher than what we have
recorded. They’re wiping out other
species. If we don’t act soon you’re
going to lose the lobster fishery throughout the northeast. We need an emergency opening of both the
commercial and recreational black sea bass fishery…”
Of course, scup and black sea bass have been living
alongside lobster, crabs, shellfish, flounder and many other creatures for tens
of thousands, if not millions, of years without fishermen to keep them from “devour[ing]
everything else," and the local ecosystem seems to have gotten along pretty
well.
If anything, it was an overpopulation of fishermen, not
fish, that put various species at risk.
Off the coast of China, a strange and very dark
sort of ecosystem management, that may be replacing the natural order that evolved over the ages, is playing out right now.
According to a
recent article in Hakai Magazine,
despite at least twenty years of essentially unregulated industrial fishing,
China has been able to maintain consistently high levels of harvest.
That seemed so unlikely that the folks who make their living
studying fisheries and their impacts on fish stocks thought that the Chinese
government was inflating the landings numbers.
Now, according to Hakai, researchers
in British Columbia are looking at the Chinese numbers in a different
light. They believe that the harvest
numbers are more-or-less accurate, and think that they can be sustained because
the Chinese have effectively, if unintentionally, created a sort of engineered
ecosystem in which fishermen eliminated most of the large oceanic
predators in the region.
The article explains that
“Killing predators allows prey numbers to boom and, much like
how deer populations have exploded in the United States since humans extirpated
wolves from much of their range, this approach has allowed fish species lower
on the food chain to retain high numbers.
And because predators typically need to eat 10 kilograms of prey to add
one kilogram to their own weight, fishing out predators tends to increase prey
catches by much more than it reduces predator catches, the study authors say.
“…China’s approach—which is similar to that of other Asian
countries such as Indonesia, Thailand, and the Philippines—has downsides, such
as degrading ecosystems and lowering biodiversity…
“But if [Chinese fisheries managers] follow the US practice
and implement single-species management, their catches will decrease…That’s
because single-species management in effect creates extra competition for
fishers…Allowing some fish to grow larger means more big fish eating more of
the fish that humans also target.”
The sort of “ecosystem management”—or, perhaps, “ecosystem
non-management”—is the conservationists’ nightmare, and it effectively reduces
the ocean into a sort of food-fish factory in which the naturally-established
food web has been almost completely disrupted.
It is a far cry from the sort of ecosystem management envisioned by Pew
and other conservation advocates, the late Commissioner Baird or the
Mid-Atlantic Council’s Guidance Document.
And as consistent as yields have supposedly been, some scientists warn
that a crash will inevitably come.
However, it is easy to see how such “management” might be
attractive to a government that seems to care nothing for natural processes or
wild places, and is obsessed with the rubric of “creating jobs” and “economic
gain.”
Thus, as we move down the road toward ecosystem management,
it is essential that we keep our eyes on the ultimate goal of healthy, intact
ecosystems that can provide fisheries that are sustainable
in the long term.
We must not allow ourselves to be seduced by the promise of engineered ecosystems that strip natural systems of their essential integrity and replace it with a structure that may or may not be sustainable, but is designed solely to reflect current social and economic values.