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The otter belongs to the indigenous species in Estonia. Its senses of hearing and smell are good, and it detects moving objects both in water and on the ground easily. But it may not notice an observer sitting motionless on the bank, and as we see, the extra lights and the video camera are not bothering it. It is a very mobile animal whom even researchers find difficult to monitor.

 

Faithful viewers of the spawning camera have noticed that the otter is not active for long in the hunting area. It allows the spawning ground to calm down and appears again after some time. Windy weather and swirls on the water favour successful attacks on fish that lose their wariness during spawning.

 

The number of otters in Estonia has varied greatly; at the low-water mark in the 80ies of the last century they were estimated at only about 500 individuals but today the number  has tripled. Toxic substances in the environment and intense hunting is thought to have been the cause of the intermediate decrease.

 

The increase in the abundance of otters in turn evidently decreases the number of an alien species, the American  mink, since the stronger otter drives off the brazen rival from its territory. These changes do not occur quickly however, but gradually over  time.