fisheries

Sea sharing or sea sparing: How should we manage our oceans?

What with Brian Cox spending an hour explaining the importance of body size in ecological systems, and then prime time marine conservation courtesy of Hugh Fearnley-Whittingstall’s ongoing Fishfight, I feel that my research interests have been rather well covered by TV of late. But whereas I have nothing but praise so far for Cox’s Wonders of Life, I find myself somewhat more ambivalent in my views of Fishfight. On the one hand, it is fantastic to see the issue of marine conservation gain such prominence. Hugh F-W is an excellent and extremely savvy campaigner, and his energy and drive to reduce the wasteful practice of discards (subject of the first Fishfight series) has had a real, positive impact at the EU level. Of course, we need to make sure that the fish now landed instead of discarded at sea actually make it to market, rather than landfill – but that’s not to take away from what Fishfight achieved. And the focus of this second series, on marine protected areas, is also a really important issue – few would argue with the central tenet that we should take better care of the marine environment, and that protecting certain areas should be a part of this. Neither am I entirely averse to using shock tactics to elicit an emotional response in the audience – indeed, I attempt just this in my marine conservation lectures here in Sheffield, where I channel Jeremy Jackson in documenting the often calamitous history of human impacts on the ocean.

On the other hand, however – and notwithstanding the considered input of scientists whom I know, like and respect such as Alex Rodgers and Callum Roberts – we need to recognise that Fishfight is a campaign, and campaigning TV by its very nature is not especially fussed about issues of balance. This is the point made by SeaFish in their response to the series. SeaFish were derided on Twitter last night by George Monbiot as an industry quango whose interest is "minimum of conservation and maximum of exploitation", but actually they are a respected body who take science pretty seriously - although as an industry body of course they consider the social and economic as well as the ecological consequences of marine environmental policy. They have been making the point that MPAs in the UK ought to be established based only on sound scientific criteria – the reason rather few have so far been agreed is that often we lack these data.

Now, I used to be of a similar view to the Fishfight gang – that the priority ought to be just establishing  MPAs, on the assumption that even if they were suboptimally positioned, any protection of any area would be better than none. Then I started talking to people who study these things and was politely told that, actually, a poorly designed MPA can actually do more harm than good. So, my view now is that MPAs need to be carefully designed, set up with specific and explicit goals, and not simply placed willy-nilly.

More generally, and as always, the truth will usually lie somewhere between environmental campaigners and industry groups. Some scientists have been quite vocal regarding the oversimplification of complex issues that is inevitable in campaigning TV. Marine conservation biologist Mike Kaiser, for example, has been quite active on Twitter putting across a fisheries science view, and I agree with this blog post by Jess Woo, that framing this campaign in terms of a ‘fight’ is unfortunate – “the last thing marine conservation (and particularly fisheries management) needs is a ruckus”.

All of which has got me thinking: what does marine conservation need? Well, some kind of clear vision would be useful, regarding how we balance the needs of conservation with feeding 9 billion people. There have been studies looking at this from a fisheries perspective, but it struck me that there are real parallels here with the land sharing vs. land sparing debate in terrestrial conservation. Should we concentrate conservation effort into the preservation of wild areas, and exploit other areas for food production as intensively as we can? Or should we aim for a more balanced approach, seeking a way to allow human activities and nature to coexist? In farming terms, this is the difference between a mosaic of industrial farms interspersed with nature reserves, and a more extensive system of wildlife-friendly farms.

The obvious upshot of this terrestrial debate is that if you want a large network of fully protected nature reserves, you have to balance that with farming the fuck out of what’s left. Translating this to a marine context, a network of no-take MPAs requires fishing the fuck out of unprotected areas. There is no real incentive for more responsible fishing outside the MPAs: the focus should just be on productivity. So the depressing images of dredged and trawled habitats that Fishfight uses to tug the heartstrings would not disappear if MPAs were widely established. In this case, you’re pinning an awful lot on not only the (widely supported) in situ success of MPAs, but also in their (often positive, but more variable) spillover effects. Responsible fishing, by contrast, requires more extensive areas to be exploited, which may limit the extent of fully protected MPAs.

More generally, whilst we should be cautious extending the fisheries—agriculture analogy too far (fishing, remember, still largely targets wild, and often highly mobile organisms), I think it does provide some useful context. Ray Hilborn, a fisheries ecologist who also happens to be a farmer, has commented on this before: how farmers are praised for bringing the landscape under the plough in order to produce food, whereas fishermen are castigated for doing similar (often in far more hazardous circumstances). Let’s just remember that (to use Oxfam’s terminology) the social foundation of access to an adequate, healthy food supply is of equal importance to the environmental ceiling of preserving biodiversity. If we get marine management right, we should be able to do both. I’m not convinced that starting a fight with some of the most important and knowledgeable marine stakeholders is the best way to achieve this.

Putting facts in the way of a good story

Or: 100 cod in the North Sea? I’ve just had a nice weekend almost completely away from screens of all kinds, and was starting to think ‘perhaps it’s time to curtail some of my online activity <cough> Twitter <cough>’. But a quick scan down my timeline on a Monday morning couldn’t hurt could it?

Best laid plans and all that… One of the first things I saw was this, from @rivercottage: Just 100 cod left in North Sea. Now I’m a big fan of Hugh F-W, I own (too?) many of his cookbooks, have eaten in his canteen, and admire his campaigning work. BUT: Just 100 cod left in North Sea? Shurly shome mishtake?

I kept scanning, and the same figure kept appearing: 100 cod in the North Sea. All of these tweets linked to a Daily Telegraph story which I duly looked up when I got to work and there it was, under the headline “Just 100 cod left in North Sea” and the only marginally less ludicrous subheading “Overfishing has left fewer than 100 adult cod in the North Sea, it was reported”: a summary of a recent Cefas survey of catches at European ports. (To be fair to the Telegraph, an almost identical piece appeared in (hold your nose) the Mail, although the headline there made the made the ‘100 adult cod’ claim more clear.) Now I know people at Cefas, I trust them to do good surveys (although there’s no link to the actual report in either the Telegraph or the Mail piece, and I can't find it on the Cefas website), so could this 100 cod figure possibly be true?

Short answer: No. Of course it couldn’t.

What the survey found was that last year, “fishermen did not catch a single cod over the age of 13”, and Chris Darby of Cefas is quoted as saying that this suggests “there are fewer than 100 such fish in the whole North Sea”. This rather uncontroversial statement from Darby is the source of the headline and thus, the Twitter meme. Anyone reading the article, though, will see that the survey did find 191 million 1 year old cod, 18 million 3 year olds, and 65,300 tons of cod aged 3 or more years. So "Just 100 cod left in North Sea" is, as @BobOHara put it, an impressively wrong headline.

But what about the subheading about adult cod? Do cod mature as late as 13? No. From Fishbase figures, North Sea cod mature at 3-4 years. So a good proportion of those 18 million 3 year olds, and most of the 65,300 tons of 3+ y fish, will be adults. Subheading debunked too then.

As for the wider issue of overfishing and the state of the cod stock in the North sea, there is some information in the article, namely that the 65,300 tons of 3+ fish is a reduction from the 276,000 in 1971, “a peak year for cod population”, although no indication of whether the 2011 figure is any kind of historic low. But the number of 13+ year old fish is presented in glorious isolation: although no fish of that age were caught in 2011, I have no idea from this article when last such a fish was caught. I suspect some time ago, for a couple of reasons.

First, although the article quotes a maximum age for cod of 25y, which is indeed the figure given in Fishbase (taken, if you follow through to the references, from a 1974 Collins Guide to the Sea Fishes of Britain and North Western Europe book), looking at stock-specific data, again from Fishbase, gives one figure for North Sea cod: 11y (and this from a study published in 1959).

Second, an anecdote: way back before I started my PhD I worked for a while at Cefas. I shared an office with a guy who was interested in the age structure of cod stocks, and who used the annual growth rings on cod otoliths (inner ear bones) to get a handle on this. While I was there, someone sent in an otolith with 7 annual growth rings taken from a cod caught in the Irish Sea (as I recall; so a different stock, but still…). He was over the moon, because cod as old as 7 were so scarce in his dataset. That was 15 years ago.

Even if we accept that 13 is an attainable age for North Sea cod, then, it’s certainly a ripe old age, so saying from these data that there are 100 adult cod left in the North Sea is like saying there are 12,640 adults living in the UK based on the number of centurions.

I don’t want to downplay the perilous state of many fish stocks, nor the fact that overfishing is primarily what’s led them there. Another statistic in the Telegraph piece is sobering: the Cefas team estimated a 2011 population of 600 cod aged 12-13, of which 200 were caught. This tallies with another personal anecdote, this time from my undergraduate project working on data obtained from tagging North Sea plaice. These tags were returned to Cefas by fishermen when they caught a tagged plaice. We reckoned on a 30% return rate within a year. So: chuck a commercially important adult fish into the North Sea, and it has about a 1/3 chance of being caught within a year. That’s pretty intensive fishing. Likewise, there’s a load of good work – much of it by Cefas scientists – showing for instance how the biomass of big fish in the North Sea is massively reduced compared to predictions of the situation with no fishing.

Given this background, isn’t it perhaps a good thing to highlight fisheries in crisis? A few people I interacted with on Twitter over this seemed to think so, for example @oceanCO2 said title is certainly misleading but the article itself has context for the numbers. As you say ‘100 cod left’ does catch the eye! and @S_Danielsson wrote situation bad even if tweets are a bit oversimplified, 93% of NS cod are caught before reproductive age. Here and elsewhere both have made reasonable points, but I cannot agree that using misleading numbers to make a point is ever justified. In this specific case, just look at the responses of some in the fishing industry, for instance @LapwingPD972 who’s been fishing the North Sea for 33 years: Who are these people that say there is only 100 mature Cod left in the north sea,OMG invitation to anyone,come away on my boat to see fish to which @AjaxAH32 (skipper with 30y experience) replied I thought it was 1st of April Brian.

This matters because the relationship between fishers, scientists and conservationists in the UK is often fraught; but listening to various talks at the Oceans of Potential meeting in Plymouth last week I really felt that real progress has been made, with a focus on the business case for sustainability which everyone can buy into. Silly headlines – seemingly designed to be picked up and circulated without thought around Twitter – set back these efforts and risk returning us to a harmful new cod war of words. More generally, you really don’t strengthen your case by simply parroting obviously nonsensical numbers.

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Postscript (19/09/12)

Since I wrote the above, Defra have released an official myth bust statement, worth quoting in full here:

The myth: An article in The Sunday Times claimed that ‘fewer than 100 mature cod are left in the North Sea’.

The truth: This is completely wrong, in fact we know there to be around 21 million mature cod in the north sea. Cod start to mature from six months old and are fully mature at age six.  There are a small number of cod over the age of 12 years old which has always been the case in the North Sea even when fished at lower levels in the 1950s and 1960s. Cod older than 15 have never been recorded in the North Sea.

So - the Sunday Times, Telegraph and Mail were out by a cool factor of 210,000…