European otter’s are warm blooded top predators usually associated with rivers and other water bodies, even coastal areas. They are widely distributed in Europe although they have suffered a significant decline (due to toxic effects of pesticides and habitat loss) in most European countries in the 1950s. Otters have short limbs with webbed feet and claws. They have sensitive whiskers around their snout to help detect prey and two layers of fur: a thick waterproof outer one and a warm inner one. Otter’s are exceptionally good swimmers and fish catchers but can only hold their breath for 20 seconds while diving for prey.
The otter’s diet consists mainly of fish but can also include birds, insects, frogs, crustaceans and sometimes small mammals. They may inhabit any unpolluted body of freshwater, including lakes, streams, rivers, and ponds, as long as there is good supply of food. The length of the territory depends on the density of food available. Males and females will breed at any time of the year, and mating takes place in the water. After a gestation period of about 63 days, one to four pups are born, which remain dependent on the mother. The cubs disperse at 14 to 15 months and venture into new areas to find their own territories. Hunting mainly takes place at night, while the day is usually spent in the otter’s holt (den) – usually a burrow or hollow tree on the riverbank which can sometimes only be entered from under water
The main factors that contribute to making the otter’s life very hazardous are loss of habitat, poor road crossings and pollution. Habitat destruction through the building of roads, houses, drainage schemes and the loss of previously undisturbed riverbank systems are the primary reason. Poorly designed bridges and road crossings can be impassible to otters during flood events, forcing otters to cross the road where they can be injured or killed by road traffic. Pollution, particularly pollution that causes a fish kill is detrimental to otter population.
The rivers banks have been disturbed throughout the Mulkear catchment. Artificial otter holts will be installed in selected sections of the watershed to provide shelter / den habitat for them. These holts will be monitored by Inland Fisheries Ireland to determine the level of use by otters. It addition, removal of invasive riparian vegetation will improve otter habitat. Also instream habitat restoration will improve the carrying capacity of fish in the catchment. This will increase the density of food in the watershed and thus hopefully allow for a higher density of otters.