The Otters’ Tale. Simon Cooper

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СКАЧАТЬ the birds to worry about, nobody gave much more thought to otters and, being such secret animals, few had any real idea what was happening to the population as the insidious chemicals did their worst. This is how it happened.

      Being top of the food chain is all very well, but the implication is that you prey upon everything below you. That’s fine just so long as your favourite foods – eels and fish, in the case of otters – are good to eat. By the early 1960s this was far from being the case. Eels, which live for 10–20 years in ponds, were absorbing the organochlorines into their bodies at a rate of knots from a diet of similarly affected grubs, earthworms and insects. The same thing was happening with fish from their diet of invertebrates: nymphs, snails and all those other bugs you find in a river. But the chemical pass-the-parcel wasn’t killing outright the otters or the things they ate. There were no corpses littering the river bank – if there were, things might have turned out differently. No, otters were hit hard because, with little body fat to act as a buffer like, say, in the eels, the sub-lethal poisoning went straight to the reproduction organs, slowly rendering the population infertile. Otters were not dying, they were dying out.

      It is a hard case to make from an emotional standpoint, but it was otter hunts that were the greatest guardians of Lutra lutra during this time. They had a vested interest, that was true, but nobody was closer to the lives of the otter. It is counter-intuitive, I know, but when it came to habitat protection and preventing uncontrolled extermination, the hunts were the otters’ best friend. One hunt in Dumfriesshire even went to the lengths of importing otters from Norway for reintroduction into the wild after a localised population crash. By the early 1960s the declining population was more than just a local occurrence; packs up and down the country were reporting fewer and fewer otters. Some packs closed down. Others hunted mink instead. The remainder changed their method of hunting, reducing the kills from 50 per cent of all otters chased to 15 per cent, limiting, as far as it was possible, those kills to old or sick otters. By the time otter hunting was finally banned as part of an Act of Parliament that gave the animals protected status in 1978, the fifteen otter packs that remained were killing just 150 otters a year between them.

      The threat of extinction was never just from hunting, but as the news of the otter decline filtered through to the wider population during the 60s and early 70s this was what took the brunt of the blame, as the anti-hunting lobby gained a voice. Other voices called for investigations, and reports were duly produced. Water quality, habitat destruction, disturbance through human activity and even the lowly mink were the four reasons generally cited for the decline of otters, but rarely was the systemic poisoning given the prominence we now know it deserved.

      However much it was wrong, it was hardly surprising that mink took part of the rap; a non-native species first imported in the 1920s, it had adapted to life in Britain pretty well, the population gradually expanding over time, with regular boosts from escapees from mink farms. The European mink, Mustela lutreola, are, as the second half of their Latin name suggests, related to otters, part of the mustelid family. They are more gregarious than their larger cousin (they are about one-third of the size), and you are far more likely to see a mink than an otter as they are less wary of people, preferring to be out and about during the day. The mink were blamed because nature abhors a vacuum. As the otters disappeared, the mink expanded into the vacant space, people assuming that the mink, with a reputation for being vicious, had driven out the otters. Nothing could be further from the truth. Today, with otters in the ascendant, mink are finding themselves marginalised, and their population is declining.

      Habitat destruction, mostly in the relentless process of urbanisation, will always be an issue for otters. Actually the worst of the damage was probably done in the 1940s and 50s when, again in the name of food production, vast swathes of otter-friendly wetlands were drained and thousands of miles of rivers straightened and dredged. Disturbance? Well, that was cited in the form of more leisure uses for rivers – boating, fishing, canoeing and so on – but otters are pretty tolerant of minor human incursions into their territory and no amount of daytime splashing would have had a significant effect. Water quality (aside from the organochlorines) was actually by this time going in the opposite direction, improving rather than worsening. The River Thames is often cited, reaching its polluted nadir in 1957 when classified as a ‘dead’ river, incapable of sustaining a fish population. Since then, along with most other rivers, the situation has improved, with salmon now regularly running up the capital’s river. Confusing? Well, only if you were directed, as most people were, to look in the wrong places. But for those close to the science, otter postmortem data was tightening the noose around the neck of organochlorines – the problem was that nobody in power was prepared to pull the lever that consigned them to death instead of the otters.

      Finally, a report in 1968 that charted the catastrophic collapse in otter numbers captured the headlines, leading to a general acceptance, albeit grudgingly in certain circles, that organochlorines were the problem. However, vested interest and inaction delayed the widespread banning of their use until 1975. This you might think was a cause for dancing in the street, but they were simply replaced by the equally bad organophosphates the following year with, almost unbelievably, the original chemical continuing in use for commercial bulb farming in Cornwall and the compulsory practice of sheep dipping right through to 1992. In that same year, the authorities finally called time on organophosphates, replacing them with synthetic pyrethroids. Relief? Well, not really. The synthetic substitute, rather than infecting the food chain, went a step further by wiping out entire groups of invertebrates – so the very insects that fed the fish that fed the otters were disappearing. This new menace was finally banned in 2006.

      I wouldn’t be at all surprised if your head is spinning from all these dates and scientific terms, but I chart it because it is truly amazing that, despite fifty years of sustained attrition, albeit unintentional, otters are still with us today. As with everything to do with these secretive creatures, it is hard to pinpoint the exact moment when the population reached its lowest point, but most observers seem to agree that it was some time in the 1990s – by then it was estimated that otters were only present in a handful of English counties. In Wales, Scotland and Ireland, with less intensive agriculture, the numbers had held up better. But the long road to recovery, which continues to this day, had begun. It was never going to be a fast journey; the ‘organos’, with their various suffixes, have to dissipate gradually from the food chain. Otters are not the most prolific breeders at the best of times, their progress tied to the health of the rivers and the availability of food. Fortunately they hung on in enough places to keep a breeding population alive; the areas mostly away from agriculture and industry. And that otter society requirement for the juveniles to travel great distances to find new, unoccupied territories had started to disperse a new population nationwide.

      As luck (they finally got some) would have it, they had some breaks along the way: more legal protection, better environmental oversight of the watercourses and an explosion in the crayfish population – one of their favourite and most nutritious foods. All of this culminated in a survey published during 2011 that had found otters in all the forty-eight English counties, Kent being the last piece in the jigsaw. But don’t be under any illusions that the danger is over; they remain rare and under threat.

      Kuschta knew nothing of her rarity, nor the perilous past her recent ancestors had trod to bring her to this point. All she knew was that The Badlands should be her home. A place good for otters, bad for people, as you’d struggle to walk across this landscape without considerable difficulty and deviations. A very long time ago this was water meadows, low-lying land in the flood plain that was deliberately ‘drowned’, covered by water diverted from the river during the winter and spring, to boost the growth of grazing pasture for sheep and hay making. It didn’t happen by accident; seventeenth-century Dutch engineers had been engaged by the large landowners, church and gentry to dig side streams or, as they are correctly known, carriers that were regulated by wooden hatches all along the valley that enabled and controlled the flooding. If you think of a human skeleton with the river as the spine and the ribs as the man-made channels, then you will get some idea of the layout. Long abandoned to nature, the defunct Dutch engineering now defines this landscape.

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