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Otters in England back from the brink of extinction

By Emma McNeil - 15 Nov 2010 13:28:1 GMT
Otters in England back from the brink of extinction

The european otter (Lutra lutra) is making a remarkable recovery from the brink of extinction in England's waters. The Environment Agency now believes that England's otter population will have made a full recovery within the next twenty years.

The fifth otter survey of England took place between July 2009 and March 2010. It examined 3,327 sites across England looking for evidence of otters. At the time of the last survey in 2002 36% of the sites showed the presence of otters.

The recent survey showed otters were present at 58% of the sites surveyed. Otters are now found in every county in England except Kent. In some areas it seems the otter population has already reached it's maximum capacity.The recovery has exceeded the targets set for 2015 in the UK's Biodiversity Action Plan.

The otter population began to drop in the 1950s and this decline continued at least until the 1970s. The evidence suggests that the main cause of this decline was the increased use of endocrine disrupting chemicals (EDCs).

EDCs are notorious for their tendency to biomagnify and bioaccumulate in the food chain. This means that animals near the top of the food chain (such as otters who eat mostly fish) are exposed to a greater amount of the toxins. EDCs have been shown to lower reproductive success in animals such as otters.

According the Environment Agency the otter's comeback is largely thanks to restrictions on the use of these harmful chemicals on Britain's farms. Otters were also helped by the introduction of legislation making it an offence to deliberately kill or harm an otter (this includes trapping and removal).

Although there should be no downside to the recovery of an indigenous mammal population the success of the otter may lead to conflict between fisheries owners and otters. The Environment Agency provides information for fisheries owners to help them minimise the potential stock damage from otters.

Otters have also benefited from the overall efforts made to imporve the quality of water in England's rivers and their revival shows just how great the improvement has been. Paul Raven, Head of Conservation and Ecology at the Environment Agency explained the significance: "The otter is at the top of the food chain, and as such is an important indicator of the health of English rivers. The recovery of otters from near-extinction shows how far we've come in controlling pollution and improving water quality."

Defra Minister Richard Benyon praised the work done to improve England's aquatic environment but cautioned that there is still work to be done: "Although our rivers are the healthiest they have been for some time, there is always more that can be done to improve water quality and help wildlife return to our rivers. We will continue to work together to deal with pollution problems where they exist in a way that is effective."

Otter populations in other parts of the world are also recovering. Populations of sea otters in California appear to have increased over a 10-year period. It also appears that the population of giant otters in Peru is increasing helped by the ban on the trade in its fur.

In July the hairy-nosed otter previously believed to be extinct was photographed using a trap camera in the Deramakot Reserve in Borneo. The hairy-nosed otter had last been recorded in 1997.

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Topics: Endangered Species / Water Pollution