Climate change

June 1, 2010

Trawling for snake oil

Filed under: Declining fish stock, Global Warming, Livestock's long shadow — Barry Brook @ 11:43 am

A new guest post by Geoff Russell — only mildly climate-change  related, but definitely ‘food for thought’ in the context of sustainability of natural resources (and bad science)…

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The last couple of weeks have seen a few things tickle my particular itch … the linkages between nutrition, food security and climate change. The first is a long overdue piece in New Scientist on omega-3 oils by Sanjida O’Connell. I called these the new snake oil in Perfidy and the NS article does a good job of explaining the dodginess of the evidence for the many wonderous effects claimed for omega-3s.

The second was stunning vision on ABC TV’s Catalyst program of trawling deep in the southern ocean. Catalyst got a dishonourable mention in Perfidy for swallowing the omega-3 myths hook line and sinker in a singularly silly program back in 2006. But more recently Catalyst redeemed itself with a brilliant piece on antarctic ice which should be running on a (nuclear powered) big screen on a continuous loop in mainstream malls all over the planet.

Scientists come second in race to trawl southern oceans

In last week’s Southern Ocean story, Catalyst journalist Mark Horstman was embedded with scientists busily trawling (i.e., trashing) an area to find out what it contained so they could protect it. Don’t worry, I don’t quite understand the logic either. The theory seems to be that if you give people a list of what’s in an area they are less likely to trash it than if you just ask them politely to stay out.

But the NS article and the Catalyst piece became intimately connected by the first major discovery of the scientists … namely that they weren’t the first people to scrape a big metal frame with a net on it along the ocean floor. Some of the world’s fishing fleet had beaten them to the punch in an area supposedly protected by international law. The images of trawler scrape marks and dead ocean bottom were ominous. Why ominous? Consider the odds of the scientists just happening to drop their camera and trawl frame on the only trawled area in the massive expanse of ocean below the 60 degree latitude. It would be far easier to find a needle in a haystack. Clearly, plenty of trawling has been taking place, and we aren’t just talking about a few navigationally challenged lads in a tinny throwing a hook over. The trawl marks also show, of course, that preparing a species inventory is unlikely to keep fisher people out of the area because some already know what’s down there and they want it … so ends the case for the prosecution.

Climate change and hunting for fish

Capture fisheries, as distinct from aquaculture industries, are just wildlife hunting industries and wildlife is intrinsically unproductive … which is why hunter gatherers were displaced by farmers. The graph shows that capture fisheries are levelling off at about 100 million tonnes per annum. This is about 1/3 of the weight of terrestrial farmed meat, and has about 10 percent of that meat’s caloric value. Farming involves selective breeding, hormones, antibiotics, rubber gloves, artificial insemination and all manner of strategies to improve on mother nature’s relatively dismal productivity. Providing food for people just isn’t an evolutionary imperative.

The leveling off in capture fisheries shown in the graph hides the more detailed picture which is a gradual decline in the trophic level of fishery captures as a succession of crashes means a constant search for new species or new areas of the same species to replace those which have crashed. This just means that fish eaters are gradually eliminating the bigger fish at the top of the food chain and working their way down the food chain.

But humans aren’t just knocking off top predators and disrupting ocean food chains, the changing ocean temperatures are kicking in synergistic effects. Some people may recall a Catalyst story on the rise of jellyfish in the sea of Japan. This isn’t just a one off isolated ecosystem imbalance, but part of a much wider class of mechanisms which is only just beginning to be recognised and investigated in detail.

Ocean wildlife systems are extremely complex with food webs which have long subchains and many interconnections. Only in the North Sea are there decades worth of catch and survey data not only of the targets of human fishing, but of the fundamental supporters of the whole edifice, the little things, the microalgae and plankton communities. Correlations between the populations of a range of ocean animal communities are changing with temperature and interacting with human exploitation of the top predator … in this case cod. Analyisis predicts that the movement is toward a new system which is being dominated by jellyfish near the surface and crustaceans down deep. Some people will welcome the crustaceans, but jellyfish are a rarely aquired taste.

Other jellyfish increases are being measured in the northeast Atlantic and elsewhere. Jellyfish are predators of fish larvae, can kill fish in aquaculture net-pens and can do serious damage to power station water intake systems. They have a capacity to dramatically change ecosystem structure and function in ways people don’t enjoy … stinging doesn’t earn them many friends either.

On a regional level, CSIRO’s fishery scientists predict that our changing climate will bring both reductions in ocean fishery productivity levels and range shifts.

Fish farming is growing at about 6% per annum and is filling the void left by this continuous stream of crashes in capture fisheries. Aquaculture is increasingly turning (human) food into (fish) feed. It has become yet another drain on the world’s grain crop, along with factory farms, feedlots and biofuels.

What drives demand for fish?

So what drives the global demand for fish and why, in particular, would fishermen face the formidable logistical and financial challenges of trawling a couple of kilometers deep in the southern ocean?

At a rough guess, it’s partly because every fresh faced wanna-be TV food guru tells people that fish is healthy because it’s rich in omega-3s. At a second rough guess its because the ACCC allows Meat and Livestock Australia to lie about omega-3s in red meat being brain food without sanction. At a third guess, I’d blame the not-so-fresh faced nutritionists at the CSIRO who are also happy to cherry-pick science to sell their fishy diet books. You may recall that CSIRO’s famous diet isn’t just a red meat diet, it also advises people to eat double the national average fish intake. This diet has been translated into 17 languages so it is effectively telling a substantial part of the planet that a diet which requires trashing oceans and emulating Australia’s world best practice deforestation and extinction rates to produce bucket loads of red meat is better than alternative diets which are more environmentally benign. The fact that this isn’t even an accurate representation of the scientific results doesn’t seem to bother them at all. A new Total Wellbeing Diet Book has just been launched confirming that CSIRO continues to advocate trashing the planet’s oceans and maximising every person’s greenhouse emissions above and beyond “mere” energy use despite some at CSIRO swimming against the tide by advocating against the Total Wellbeing Diet.

CSIRO’s plan to leverage fishery collapses

But the CSIRO has plenty of dogs in this fight for nutritional brand loyalty. This is a disgusting phrase, but it is appropriate given the CSIRO Nutrition Division’s ethical standards. CSIRO are working to engineer plants to produce long chain omega-3s in bulk to take up the slack when their obedient customer base has finished exploiting not just our ocean but anybody else’s who will trade with us. A nutritionally honest message that nobody needs fish would undermine the market for these new products.

It doesn’t matter to CSIRO that the only big meta-analysis of the impact of omega-3 oils on heart attacks showed no benefits. This was done by a group called the Cochrane Collaboration. These people are rather different from many researchers, most of whom have done just a smattering of statistics during their undergraduate training. The Cochrane people are specialist statisticians and, just like in those John West salmon ads, it’s the studies they reject that make them the best. The Cochrane people may not be infallible, but CSIRO’s nutritionists need more than just good sales figures to take them on. They need evidence.

Similarly, it doesn’t seem matter to CSIRO that there have been large IQ gains over many decades in many countries which are demonstrably not due to fish. And it doesn’t matter to CSIRO that people who don’t eat any fish have lower heart attack rates than people who eat fish … I’m talking about vegans and most vegetarians. Don’t tell anybody, but some vegetarian Indian populations are letting the side down by clogging their arteries with ghee. Saturated fat by any other name still works its magic.

The Great Barrier Reef coral spawning pales into insignificance beside the seas of omega-3 hype spawned by TV foodies, CSIRO, Catalyst and even MLA, and this hype drives up the demand for fish.

Australia already imports over half the fish eaten here. We buy them from somebody else’s ocean. The same is true in many other countries where the omega-3 myth is rampant. The current mechanism whereby collapses in one fishery are replaced by a new one is unlikely to continue for long. Fishers have to run out of new fisheries some time, and fishing the Southern Ocean does rather smack of desperation.

Other omega-3 myths

But the New Scientist article provides a summary of the myths that cling to the omega-3 brand like barnacles to a pylon. In brief:

Studies that claim omega-3 helps ADHD kids are just too junky to draw conclusions from.

Omega-3 might delay alzheimer’s in rats, but large human studies have once more demonstrated that people aren’t rats. Back when I served on the Flinders University Animal Experimentation Committee, they were (and probably still are) doing plenty of work which involved giving strokes to rats. There are dozens of really good drug treatments which work wonders on stroke in rats. None of them work wonders on people. People are not rats.

When ever the micky mouse studies showing that extra omega-3 intakes improve spelling, reading or something else are done properly, they fail to find any effect.

… etc

The Maasai and omega-3s

There is one more wrinkle in the omega-3 story which also emerged last week. The Maasai. That’s right the tall bouncy African tribal group who live on blood and yoghurt … except they don’t eat much blood, if any, and haven’t done so for decades. A press release from Jena University announced that the Maasai had a perfectly healthy amount of omega-3 fatty acids in their red blood cell membranes “even though they are not ingested“. Many Maasai live on milk and maize-meal porridge … neither of which contains any long chain omega-3s (see appendix below).

The full paper by Nadja Knoll hasn’t been published yet but it promises to be an interesting read. But I’ll bet it won’t stop the trashing of the oceans in pursuit of fish to sell to CSIRO diet aficionados.

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Appendix on Omega-3s: Omega-3s are polyunsaturated fatty acids which come in various lengths. The short ones are in all kinds of foods and we use them to make the long ones. Some animal foods, for example eggs, contain a small amount of short omega-3s and a large amount of long omega-3s. Plant foods can contain 50-100 times more short omega-3s but no long ones. Similarly, milk contains no long omega-3s. The advocates of increased omega-3 intakes are talking about the long ones … the ones in the products they sell or in the products their funding sources sell.

The Maasai, mentioned above, traditionally feed their children nothing but cows milk (following weaning) until about 5 years of age. The long chain omega-3 intake advocates believe that the process by which we make long omega-3s from short ones is inefficient and that it is therefore desirable to eat the long ones directly in meat and eggs. There is also a nice story about omega-6 oils competing for the enzymes required to turn the short omega-3s into the long ones. Google the net and you will find another famously inefficient molecule, this time an enzyme, called RuBisCO. It manages to drive all plant growth on the planet despite being inefficient. Nature is full of inefficient processes that seem to get the job done.

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