Irish otter numbers may be on the rise

THE Eurasian otter has a huge range that takes in most of Europe, much of Asia and parts of Africa.

But for more than 50 years it has been declining rapidly in western Europe due to persecution, pollution and habitat loss.

In many European countries it is now extinct or very rare, though there are some re-introduction programmes being carried out.

Ireland and western Scotland have always been regarded as strongholds for the species in Europe and otters get special attention from the conservation authorities in this country with surveys being carried out on a regular basis. I understand one is being carried out at present and result are expected to be available later this year or early 2012.

They will make interesting reading. Otters are making a strong recovery in England and some other countries in western Europe. I’m seeing more otters and otter signs in this country in the past five years than I used to. I was astonished to see them fishing in Grand Canal Dock in the centre of Dublin recently. Could it be that improving water quality and more enlightened attitudes are resulting in population growth?

Otter numbers decreased in Ireland by an estimated 18% over the past 25 years.

The first national survey of otters in Ireland was undertaken in 1980-81. Thousands of sites were examined and otter signs were found in 88.2% of them. This was encouraging and reinforced the belief that Ireland was internationally important as a refuge for these beautiful animals.

But 10 years later a large sample of the original sites was re-examined and only 75.2% showed signs of occupation. A third survey was carried out in 2004-05 and this showed a further decline to 70.5%.

There is some crumb of comfort in the fact that the rate of decline seems to be slowing, but what everyone is hoping is that the next survey will show that it has been reversed. Otter numbers are highest in the south west of the country and lowest in the east. They are also more plentiful in lowland and coastal areas than in uplands.

Otters spend much of their time under water or under ground and they are normally nocturnal. This makes them difficult to count. The usual survey method is not to look for otters but to look for the spraints that they deposit in prominent places to mark their territory.

The spraints can also be analysed to give a picture of the animal’s diet. In the Irish survey 40.4% showed traces of salmonid fish — that is salmon, trout or sea trout. 35.1% showed traces of eels, 24.5% of frogs and, rather surprisingly, 24.8% of sticklebacks.

The fact that otters ate so many pinkeens surprised me, after all they are our largest land animal that doesn’t have hooves, but the high percentage of eels did not. Eels are an easier species than most for otters to catch and their oily flesh is highly nutritious. This means that the sharp decline in eel numbers in recent years, which is an international phenomenon, may be another piece of bad news for our otter populations.

Otters are not only wonderful animals, they are also a dial that indicates the health of our freshwater ecosystems. If they continue to decline we have a problem. If their numbers start to build again we are beginning to get things right.

There is also increasing evidence to show that otters kill mink and are an effective means of controlling the numbers of this species.

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