It’s good to have a positive story to report early in 2017 — one of our oldest mammals, the protected otter, is in a healthy state in the Munster Blackwater.
A new study has found the river remains an important habitat for the species, scientifically known as Lutra lutra, with evidence to show it is present along the entire catchment, ranging from the sea to small feeder streams in the uplands and including all major tributaries.
Though a threatened species in freshwater systems in Europe, the otter is still widespread in Ireland, which may come as a surprise given the decline in water quality and landscape changes.
Patrick Smiddy’s latest research in the Blackwater has found no firm signs of a significant drop in otter numbers and Ireland still remains a stronghold in Europe for the species, which also bears out the findings of previous studies in the river. Two-thirds of the 275 sites surveyed in the Blackwater were positive for the otter.
“Although direct comparisons between this and previous surveys are unwise, there is no evidence that the otter has withdrawn from any part of the Blackwater catchment during the last 25 years,” says Mr Smiddy.
His findings, published in the Biology and Environment magazine, will be welcomed by environmentalists and the regional development company, IRD Duhallow which, in recent years, has been undertaking work on three rivers in north Cork to help the local otter population.
The EU-funded IRD project, also involving Inland Fisheries Ireland, set out to improve habitats of the otter and other species in the catchments of the rivers Allow, Dalua and Brogeen.
These rivers are important tributaries of the Blackwater and a key part of the project was the placement of otter holts, or specially constructed breeding boxes, in areas where otter numbers were low.
The otter is believed to have been in Ireland since end of the last Ice Age, more than 10,000 years ago. Well adapted to water, it is an excellent swimmer. They mainly feed on fish, including salmon, trout, eels and crayfish, but also small mammals, frogs, dead animals or water birds.
Their large lungs allow them to stay under water for several minutes, though most dives last for one minute. They swim low in the water, with only their eyes, ears and nose above the surface.
An abundant presence of wildlife is seen as a sign of clean water. Like other animals the otter is a victim of water pollution, habitat destruction, road kills and fish traps. Drainage works, interference with riverbanks and vegetation clearance have all taken their toll on otter habitats in Ireland. Under the Wildlife Act 1976, it is an offence to hunt, disturb or intentionally kill an otter.