February 21, 2011
Two Thirds Of Large Fish Gone In Last 100 Years

Yet more evidence that the world's fisheries are over-harvested.

Predatory fish such as cod, tuna, and groupers have declined by two-thirds over the past 100 years, while small forage fish such as sardine, anchovy and capelin have more than doubled over the same period, according to University of British Columbia researchers.

Led by Prof. Villy Christensen of UBC's Fisheries Centre, a team of scientists used more than 200 marine ecosystem models from around the world and extracted more than 68,000 estimates of fish biomass from 1880 to 2007. They presented the findings today at the American Association for the Advancement of Science (AAAS) Annual Meeting in Washington, DC.

Their finding of the simultaneous decline of predatory fish and increase of forage fish provides the strongest evidence to date that humans are indeed "fishing down the food web" and impacting ecosystems globally. The UBC team also found that of the decline in predatory fish population, 54 per cent took place in the last 40 years alone.

Peak Fish like Peak Oil.

"It looks like we are fishing harder for the same or less result, and this has to tell us something about the oceans' health," he said. "We may, in fact, have hit peak fish at the same time we are hitting peak oil."

China's demand is growing even as fishery stocks are shrinking. So no relief is in sight.

Yet demand is growing fast, again most dramatically in East Asia. According to International Food Policy Research Institute research fellow Siwa Msangi, the rise in demand is largely being driven by China. Almost 50 percent of the increase in the world's fish consumption for food comes from Eastern Asia, and "42 percent of that increase is coming from China itself," he said.

The more China industrializes the higher Chinese consumer buying power will grow and Chinese demand for fish will go much higher.

In south Asia and Africa population growth will furnish more sources of demand. More hungry human mouths will increase demand for fish even further.

In 2011 the Earth's population will reach 7 billion. The United Nations (UN) reports that the total number of people will climb to 9 billion in 2050, peak at 9.5 billion, stabilize temporarily, and then decline. Despite the confidence with which these projections are presented, in an American Association for the Advancement of Science press briefing and presentation today the Population Council's John Bongaarts presents evidence that the actual population trajectory is highly uncertain.

What could happen depends on trends in fertility and mortality—and both variables are complex and not easy to forecast.

If technological advances are going to some day reverse these trends those advances are not coming soon enough.

Share |      Randall Parker, 2011 February 21 11:11 PM  Trends Resource Depletion

Ramez Naam said at February 22, 2011 8:08 AM:

We hit a peak (or at least a plateau) of wild fish a few years ago. Since then, however, aquaculture has taken up the slack. Fish production has continued to rise over the last decade. Almost all of that rise has been fish farms. There is still significant headroom there.

See this article in this month's Scientific American: http://www.scientificamerican.com/article.cfm?id=the-blue-food-revolution

Anonymous said at February 22, 2011 9:21 AM:

In Brazil's river Amazonas, there was a policy telling people to fish only big fish, and if it was too small you had to throw it back into the river, because it was supposedly a "baby fish". After some years: The fish had evolved into smaller fish. That is: Some fish never got big enough to be fished, and they were always thrown back, being able to reproduce more than the big fish who were caught before they reproduced.

BioBob said at February 22, 2011 11:10 AM:

"Their finding of the simultaneous decline of predatory fish and increase of forage fish"

ALL fish are predatory. The above pseudo-distinction merely indicates that smaller predators are fed on by larger predators. The smaller predators feed on plankton, etc, comprised of smaller predators of algae, benthic plants, etc. with the plants the primary producers.

"Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum."

Peak ocean production and standing crop biomass has been LONG GONE - for many decades if not centuries - in most oceans of the world. Consider the case of commerical anadromous fisheries like atlantic salmon or American Shad, in which fisheries crashed in the 1800s. Likewise, consider the effects of whaling and its crash due to resource depletion. The Grand Banks cod fishery was destroyed in the 1960s - 70s. AD Nauseum...

Sycamore said at February 22, 2011 5:52 PM:

> presents evidence that the actual population trajectory is highly uncertain

Maybe in Africa. Not that uncertain elsewhere.

xd said at February 22, 2011 7:18 PM:

What Ramez said.

In actual point of fact we have been having an over hunting crisis for quite some time in one and then another and another and lately all fields and that's what the "peak" hysteria is all about.

If you think about it in an abstract sense, we have been hunting/foraging animals, plants and lately minerals, fossil fuels, fish etc for a long time. We are a hunter gatherer species and we have been TOO successful at it and now our burgeoning global population is running out of things to hunt.

We have have to learn how to farm and our broad general intelligence has led us to discover how to farm in more and more areas.

Now we have to farm EVERYTHING and do it sustainably.

In spite of the pro-nuclear bias of many of the posters here, one day nuclear will run out. At that point we will have to farm the wind and the sun.

Likewise with our minerals. We will have to come up with recycling. An artificial mineral cycle such as used to exist in nature with the nitrogen cycle, carbon cycle, phosphorus cycle etc.

I believe it can be and will be done in spite of what the doomers say.

Chris T said at February 22, 2011 7:37 PM:

In spite of the pro-nuclear bias of many of the posters here, one day nuclear will run out. At that point we will have to farm the wind and the sun.

And one day the sun will run out (and way before that, we'll run out of materials to harvest the sun if we restrict ourselves to Earth). Everything is finite over a long enough time frame. Humanity's only real sustainable solution is to constantly increase its resource base.

Randall Parker said at February 22, 2011 10:40 PM:


I do not doubt that aquaculture will continue to grow. But read the Amazon.com review of Paul Greenberg's book Four Fish: The Future of the Last Wild Food. Note what he says about the problems associated with aquaculture.

More fundamentally, aquaculture does not show any signs of causing a radical (and needed) decrease in factory fishing vessels sweeping the oceans. So the thrust of my post, the problem of resource depletion, looks set to continue.


The unresolved energy question: Can we ever make nuclear fusion viable on the surface of this planet. If not, then we will have to shift to solar and wind power.

Our problem is that as a species we are omnivores. We do not have the forces on us that keep other predators from getting too numerous because we can shift to other food supplies.

Nick G said at February 23, 2011 10:27 AM:


I wonder what would be needed to reduce factory fishing vessels sweeping the oceans. Elimination of shared areas, and privatization of the whole oceaon, so people feel responsible for "their" area and we eliminate the tragedy of the commons? Or is the problem that governments are captured by private fishing interests?

Fusion: from everything I've read, I think it's very likely that we'll make it viable. OTOH, it will probably take 50 years, which is too long to include in our present planning horizon.

Randall Parker said at February 23, 2011 8:06 PM:

Nick G,

Given that such large areas of the oceans are not within sovereign zones I do not see how we get from where we are to a state of affairs where the oceans aren't getting heavily over-fished.

Sovereignty does not even work where lots of small governments each have short sections of ocean frontage. Look at sections of west Africa where really small countries have ocean frontage. What's the incentive to protect fish in your section of the ocean when the fish will just get captured when they swim to another nation's territory?

Nick G said at February 24, 2011 2:27 PM:

Yes, privatization is far too simplistic.

What's required is regulation by treaty enforced by navies. It can be done, it's just a social choice.

Just. Such a deceptive word.

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