American fisheries scientist and marine biologist, Professor Ray Hilborn is in New Zealand presenting at seminars titled 'The Environmental Cost of New Zealand Food Production', where he compares the cost, economic and environmental, of consuming seafood, meat, dairy and other foods.
Prof Hilborn, who teaches resource management and conservation at the University of Washington, says he became interested in the wider environmental cost of food production two years ago.
'A friend in Africa who's the head of conservation programmes for the Frankfurt zoo asked me ‘should I stop eating fish?’, and I’d never really thought about the tradeoffs before. Almost everybody focuses on rainforest or marine and doesn’t look at the connections.'
Hilborn’s report assembles information on various factors such as greenhouse gas emissions, water pollution, erosion, loss of biodiversity and eutrophication – the amount of nutrients released into the air, water or soil.
The conclusions come in several categories. Per serving, for example, the species of wild fish caught most fuel-efficiently are barracouta and southern blue whiting, but both take more energy than a serving of beef or dairy protein. Dairying produces fewer greenhouse gas emissions than beef farming, but more than most fisheries.
On biodiversity, says Hilborn, the contrasts become extreme.
Since New Zealand dairy and meat production uses mostly non-native forage, the reduction in plant biodiversity is almost total in land converted to pasture. Wild fisheries, meanwhile, rely on a naturally functioning ecosystem.
This fact is often lost on marine conservationists concerned about bycatch, for example, says Hilborn.
'The species that attract the most attention in New Zealand – dolphins, sealions – you've always got to go back to the comparison with agriculture. Those species are still there in marine ecosystems, but in agriculture we essentially plough the place down and turn it into something else.'
Hilborn is critical of a report published this month in New Zealand by Forest & Bird called the 'Best Fish Guide', which aims to advise on which fish are the most sustainably caught.
Of 74 species rated, it recommended consumers avoid 50 and had concerns about the other 24. None were rated sustainable.
'They basically look at the abundance of the stock and they then look at bycatch and things like that. It’s pretty clear how they do it, but to some extent those guys are just clueless. The idea that hoki were in danger because they were going down in abundance ... they just obviously don't understand population dynamics.
'If you look at their list and take the species in their green section, they constitute a couple of per cent of New Zealand's fisheries landings. And this is pretty typical – if you take these marine conservation agendas by themselves and say ‘what should you eat?’ they essentially say you should not eat almost all the fish in the world.
'So my question to them is ‘OK, are we better off if people then go out and eat beef, chicken and pork?’ and I think the answer is pretty clearly no! Yes, there are environmental costs in fishing, but the alternatives are also costly. Even the greenest of farms destroys the ecosystem that existed before.'