Sunday, February 26, 2017


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.”  

“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.

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