The Fish Commandments

I’m an alien. I watch things… I listen…**pauses to listen to the dishwasher** {wirwirwirwir... sounds like Vinnie, my AI ship, when he’s content, in equilibrium…} I glance up from my fish and chips meal to inspect the blue-green painted wall of my friend's kitchen and wonder whether they considered it more blue or more green. I've observed that humans seldom agree on anything.

A while ago, in my role as a limnologist on this planet, I observed a dichotomy of human perception on ecosystem behavior that had me thinking of chaos theory. In a recent blog post I contrasted traditional equilibrium-driven views with more current views for ecosystem behavior (Creative Destruction—Another Paradox?). C.S. Holling’s model recognized ecosystems as non-linear, self-organizing and continually adapting through cycles of change from expansion and prosperity to creative destruction and reorganization.

Fisheries scientists are also shifting from the traditional single-species target approach to conservation and preservation in an ecosystem-based perspective. Scientists at the Western Society of Naturalists Presidential Symposium came up with their version of the “ten commandments” for ecosystem-based fisheries scientists to follow (Fisheries, May, 2007). Here they are:


Commandment 1: Keep a perspective that is holistic, risk-adverse, and adaptive.
Out of context, the best minds do the worst damage—Wes Jackson (Berry 2005)

For marine fisheries management, this means taking into greater consideration the constantly changing climate-driven physical and biological interactions in the ecosystem.

Commandment 2: Question key assumptions, no matter how basic.
Here lies the concept, MSY. It advocated yields too high—Peter Larkin (1977)

This is a critical commandment for any science, but key to science that is advisory to fishery management decisions.

Commandment 3: maintain old-growth age structure in fish populations.
Logic surely demands that a fishery for a species having intermittent recruitment must somehow eschew the common practice of truncating the age structure—Alan Longhurst (2002)

Studies have shown that three assumptions of traditional fisheries biology about spawning females are incorrect: all eggs are NOT identical and eggs from younger smaller females and older larger females are NOT equivalent; all mature females are NOT equivalent in terms of spawning behavior; and long –lived individuals per se ARE essential for an exploited stock to persist.

Commandment 4: Characterize and maintain the natural spatial structure of fish stocks.
Broad spatial distribution of spawning and recruitment is at least as important as spawning biomass in maintaining long-term sustainable population levels—Steven Berkeley et al. (2004)

Commandment 5: Characterize and maintain viable fish habitats.
No habitat, no fish—it’s as simple as that—Anonymous

Commandment 6: Characterize and maintain ecosystem resilience.
Even though the scientists on a team may be world-class experts in their respective component fields, they are all likely to be amateurs when it comes to the system as a whole—Craig Nicolson et al. (2002)

Walker et al. (2004) describes four crucial components of resilience: latitude; resistance; precariousness; and, panarchy. The first three define an ecosystem’s capacity to maintain its current rules of organization. Panarchy refers to the cross-scale effects that can occur in both space and time.

Commandment 7: Identify and maintain critical food-web connections.
To keep every cog and wheel is the first precaution of intelligent tinkering—Aldo Leopold (1953)

Commandment 8: Account for ecosystem change through time.
Nothing is permanent but change—Heraclitus

Commandment 9: Account for evolutionary change caused by fishing.
Yet ultimately the success for fishery management may be judged not by the catch achieved in any given year or decade, but by whether it was sustained across future generations—David Conover (2000)

Traditional fisheries biology has not fully recognized the potential of fishing mortality to cause directional selection in fish populations.

Commandment 10: Implement an approach that is integrated, interdisciplinary and inclusive.
When we try to pick out anything by itself, we find it hitched to everything else in the universe—John Muir (1910)

Single disciplinary perspectives are insufficient to describe the kinds of issues raised within a more holistic ecosystem-based approach to fishery science.

So, there you have it. The ten fish commandments. The authors of the commandments believe that these should be implemented as soon as possible to avoid, or at least delay, critical declines in seafood for an ever-expanding human population.

Regarding sustainability, check out Canada’s Seafood Choice for making healthy choices for healthy oceans. There are some cool recipes in there too!

Bibliography:Berkley, S., M.A. Hixon, R.J. Larson and M.S. Love. 2004. Fisheries sustainability via protection of age structure and spatial distribution of fish populations. Fisheries 29 (8): 23-32.
Conover, David. 2000. Darwinian fishery science: ‘evolution’ of fisheries science. Marine Ecology Progress Series 208: 303-307.
Larkin, P.A. 1977. An epitaph for the concept of MSY. Transactions of the American Fisheries Society 107: 1-11.
Leopold, Aldo. 1953. Round river. Oxford University Press, New York.
Longhurst, Alan. 2002. Murphy’s law revisited: longevity as a factor in recruitment to fish populations. Fisheries Research 56: 125-131.
Muir, J. 1911. My first summer in the Siera. Houghton Mifflin, Boston, Massachusetts.
Nicolson, C., A.M. Starfield, G.P. Kofinas and J.A. Kruse. 2002. Ten heuristics for interdisciplinary modeling projects. Ecosystems 5: 376-384.
Walker, B., C.S. Holling, S.R. Carpenter, and A. Kinzig. 2004. Resilience, adaptability and transformability in social-ecological systems. Ecology and Society 9 (2): 5

Nina Munteanu is an ecologist and internationally published author of novels, short stories and essays. She coaches writers and teaches writing at George Brown College and the University of Toronto. For more about Nina’s coaching & workshops visit www.ninamunteanu.me. Visit www.ninamunteanu.ca for more about her writing.