The return of the otter in England is causing problems for commercial fisheries, which are resorting to unusual remedies. Otters threatening an angling club's prize fish, worth thousands of pounds, are being kept away with a novel deterrent – lion dung.
The regal poo from London Zoo is "very, very pungent", and is the key ingredient in a smelly protective spray being used around its fishing lakes by the Whitbourne Angling Club in Worcestershire. And club members say it's working.
Otters turned up 18 months ago at the fishery, which is connected by a brook to the River Teme, and began to eat some of the large carp, tench, perch and roach. But once the lion dung spray was used, they "vanished overnight", according to club secretary Ian Miller.
Although the remedy seems bizarre, its use is being watched by the Environment Agency, which is responsible for angling in England and Wales.
There is now increasing conflict between Britain's resurgent otter population and commercial fisheries. Many fisheries hold enormous "specimen" fish, such as carp weighing 50lb, which are caught by anglers but always put back to be caught again.
If they are lost to otters, the cost of replacing them can be staggering. "Big fish are incredibly valuable – a 40 to 50lb mirror, common or leather carp would cost £25,000 to replace," said Mr Miller, a retired agronomist, whose own most valuable fish is a 23lb mirror carp, worth more than £1,500.
Under the Wildlife and Countryside Act 1981, otters are protected and cannot be killed. Only "passive" defences can be used, such as otter-proof fencing – the cost of which can be prohibitive.
Otters disappeared from eastern and central England in the mid-Fifties, probably because of the introduction of organochlorine pesticides. In the Nineties, as river water quality improved, otter numbers began to grow. Last year, the Environment Agency's fifth otter survey showed the animals had returned to every English county except East Sussex and Kent – which they are expected to reach in the next decade. This is regarded as a wildlife triumph but is a major headache for the owners of stillwater fisheries.
Mark Lloyd, chief executive of the Angling Trust, the representative body for anglers in England, said: "It seems to be localised, but where it's a problem, it's severe. Many of our members have had huge numbers of fish killed. It's difficult, because we can't support culling. For many anglers, seeing an otter makes their day."
The Environment Agency recognises the problem and will provide 50 per cent funding for otter-proof fencing. A spokeswoman said: "We don't have any evidence lion-dung spray is a long-term solution, but we're interested to see how they get on. Otters are intelligent. If the spray is used often, they may figure out there are no lions roaming around."
Mr Miller was given the idea by a gardener who uses lion dung in a spray to keep cats away from his herbaceous borders. "It certainly works with cats," he said. "We thought the smell of a big predator would deter otters as well."
The club buys its lion dung from London Zoo for £12 for a 10kg sack. "It's browny and dried. Imagine a strong version of ordinary cat poo – it's very, very pungent indeed," said Mr Miller.
Club members mix two kilos of dung in a 50-gallon tank with other ingredients, including beer, and leave it for a fortnight, before spraying. "I've nothing against otters," Mr Miller said. "They're beautiful creatures. But you couldn't afford to have one come in."