Economist Jeff Sachs promotes aquaculture and global fisheries controls in the July Scientific American. Included are some interesting factoids — e.g., China is now producing about 2/3 [by weight] of global farmed fish. I’ll look into this further to verify how much of that Chinese production is “good fish”, like carp or catfish raised on plant matter, as opposed to carnivore “bad fish”, like salmon — raised on other fish species. Farmed salmon consume between three and five times their market weight in fish meal so they are a significantly net-negative food source.
…Into the breach has arrived the Blue Revolution, first in China, and now in many other parts of the world. Aquaculture yields have increased from around two million metric tons in 1950 to almost 50 million metric tons today. Thus, even though the global fish catch peaked in the late 1980s, aquaculture has enabled a continuing rise in human consumption of fish. China now accounts for around two thirds of total aquaculture production worldwide by weight and roughly half by market value.
Fish farming in China is of course an ancient activity, with several carp species grown among rice fields for thousands of years. The inter-mixing of rice production with fish farming, rather than with animal husbandry as in Europe and the Americas, made good ecological and economic sense in densely populated China. A cow requires around seven kilograms of feed grain for each kilo of meat, while a carp requires around three kilos or less. Fish farming economizes on feed grain, and of course on the land area needed to produce it.
The exciting news, however, is that recently Chinese scientists have both improved the efficiency of aquaculture and revolutionized the range of species that can be farmed. An insightful study by coastal ecologist Carlos Duarte and his colleagues in the April 7 Science documents the dramatic rate of domestication and commercialization of marine species. Of the more than 400 farmed marine species, as many as 106 have been domesticated in the past decade alone. In contrast, there has been almost no concurrent increase in the number of domesticated land species.
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When science is not ready to answer specific questions, but the political universe insists that policies must be put in place (How large a catch can the fishery sustain? Is malaria in Africa a greater problem than HIV? How rapidly will this beach erode?), the outcome is almost inevitable: Someone will rush forward claiming that the answer is at hand, and the political system, driven to cope with a public threat or desire, will likely implement some insupportable policy.
This isn’t a perfect book — but it looks to be a useful one for illuminating a topic rarely discussed in the media. MIT Oceanographer Carl Wunsch reviews the new book Useless Arithmetic for American Scientist:
…What happens when an immature and incomplete science meets a societal demand for information and direction? The spectacle is not pretty, as we learn from Useless Arithmetic, a new book that describes a long list of incompetent and sometimes mindless uses of fragmentary scientific ideas in the realm of public policy. The troubling anecdotes that authors Orrin H. Pilkey and Linda Pilkey-Jarvis provide cross diverse fields, including fisheries management, nuclear-waste disposal, beach erosion, climate change, ore mining, seed dispersal and disease control. Their extended examples of the misuse of science are both convincing and depressing. The book is a welcome antidote to the blind use of supposedly quantitative models, which may well represent the best one can do, but which are not yet capable of producing useful information.
With modern computers, it is now possible for a graduate student or a practicing engineer to acquire a very complex computer code, hundreds of thousands of lines long, worked over by several preceding generations of scientists, with a complexity so great that no single individual actually understands either the underlying physical principles or the behavior of the computer code—or the degree to which it actually represents the phenomenon of interest. These codes are accompanied by manuals explaining how to set them up and how to run them, often with a very long list of “default” parameters. Sometimes they represent the coupling of two or more submodels, each of which appears well understood, but whose interaction can lead to completely unexpected behavior (as when a simple pendulum is hung on the end of another simple pendulum). One hundred years in the future, who will be able to reconstruct the assumptions and details of these calculations?
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Bad science can be done with simple models as well. The authors, who gleefully point at others’ published errors, themselves fall into the trap of quoting mistaken concepts and ideas in which no computer model is used at all (for example, the false alarm of the failure of the oceanic wind-driven circulation). An annoying feature of the book is the unreferenced employment of provocative statements from outsiders, either as straw men to be knocked down or as support for the authors’ point of view.
An analogy may be made to the plight faced by astronomers, who ultimately managed to distinguish themselves, at least among other scientists, from astrologers. Astrologers provided welcome predictions of what was going to transpire in human lives. Are models of fisheries, beach erosion, climate and the like analogues of astrology, or of astronomy—or perhaps of something of both? Astrology led to astronomy. What will come next in large-scale computer simulations?
Politicians must make and implement public policy even when science cannot provide truly skillful forecasts. Society has to make decisions in the face of major uncertainty about the outcome. More discussion of that necessity and how to cope with it would have been welcome in this book. As it is, the authors usefully raise the alarm about the misuse of poorly understood models and the illusion that because those models are complex, they must be meaningful. In the wrong hands, the best of models can be grossly misleading. To find many examples of that, read this book.
…they report that the loss of ocean populations and species has been accompanied by plummeting catches of wild fish, declines in water quality, and other costly losses. They even project that all commercial fish and seafood species will collapse by 2048.
Dr. Sean Chamberlin of UC Santa Barbara has published a summary of the 3 November, 2006 paper “Global Loss of Biodiversity Harming Ocean Bounty” [you must be a Science subscriber to access the full text].
Worm and his colleagues call for the creation of new marine reserves, sustainable management of fishing, and tighter control of pollution. Those are well-worn recommendations, but Worm says the team’s analysis of the consequences of not taking action, especially the loss of wild fisheries, gives them greater weight. “If you can see the bottom of the barrel, that changes things.”
The national press has played up the Science article — the disaster prediction makes for good headlines. But marine scientists won’t find any new concepts here — biodiversity is well understood to be a necessary condition to healthy fisheries. Unfortunately fish don’t vote, while the fishing lobbies have a lot of $$ to spread around… So the headlines are a good thing — it’s probably not yet too late for at least some of the fisheries.
According to scientists, the current amount of catches is over three times the level that would provide optimum return in a sustainable way. Fleet overcapacity and lack of proper enforcement have been identified as the main factors… The raft of measures — proposed by the EU, Algeria, Croatia, Libya, Morocco, Tunisia and Turkey — also strengthens control measures, including the setting up of an international inspection scheme on the high seas.
We don’t know accurately what the annual harvest actually is — in any of the world’s fisheries. We do know that fishing technology, fleet sizes, and illegal fishing [plainly: piracy] have vastly outstripped sustainable catch levels.
It costs a LOT of money just to gather the population data. It costs even more money to police the pirates, especially in the remote areas of the Pacific. So we’re not at all optimistic that the magnitude of required action will be taken in time to avoid crashes similar to the Atlantic cod fishery experience.
In its July report on the illegal fishing of bluefin tuna in the Mediterranean, the environmental group WWF said that actual catches were more than 50 percent higher than the legal annual quota of 32,000 tons, set by the ICCAT.
That said, this ICCAT agreement is clearly a positive step — particularly the enforcement component of the deal:
- a global control system which covers every step of the process, from the catch to the market through to landing, transhipping and caging operations.
This post has links to the November 3, 2006 Science article that’s been making headlines.
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