There are 12 or possible 13 different species of otter in the world. The species that live in Sweden is called utter (Lutra lutra) and is the only species of otter that lives natural in Europe.
Photo: Anna Roos
Most of the otters in Europe live close to freshwater but they can also live in marine environment such as along the Norwegian coast, in Scotland and on the Shetland islands. Our otter is the otter species that has the largest geographical spread, it is found in Europe, Asia and Northern Africa.Otters are primary piscivorous but they also eat other food items. Certain periods frogs are a very important food source. Otters also eat crayfish , birds and smaller mammals. An adult otter weight between 4-10 kg. The male is bigger than the female. The otter is often active during the dusk and there for often difficult to discover. Otters can live in the same areas as the American mink (Mustela vison) and the beaver (Castor fiber) and they can sometimes be difficult to tell apart.
After the middle of the last century a dramatic decrease of many otter populations took place. In Sweden during the 1980´s were there only small populations of otter, such as on the highland of Småland, in Uppland and in scattered areas in northern Sweden.
The biggest cause of the decrease or almost extinction of otter from large areas in Sweden was likely caused by environment contaminants, specially PCB (polychlorinated biphenyl). Earlier experiment with mink has shown that PCB disturb or destroy the reproduction at levels that are found in the Swedish wild otter population. But of curse are there other reasons for the decrease of otter.
More than 85% of the otters that are sent to the museum of Natural History have died because of human activities, such as traffic and fishing. But the largest general cause to the reduction i probably environment contaminants.
Increasing
It is now obvious that the otter is increasing in Sweden an well an in our neighboring countries. In the 1980´s did the museum received 26 dead otters and during the 1990´s almost five times more, 125 otters. In the 2000´s until to day, spring of 2008, we have received double as many otters than during the whole 1990´s. It talks for it self, the numbers of otters increases.What is done for the otters?
The Swedish environmental protection agency has implemented an action program for otter.Action program -länkThe Swedish road administration working whit fauna passages to avoid that animal get killed in connection with the traffic.
Several counties make inventories of otter in their regions.
The Natural History Museum of Sweden study health and contaminants in the Swedish otter.
Compile of otter reports
Maps and reports
(Swedish)Writer Anna Roos, Department of Contaminant Research
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