Fishing restrictions is the essential protection method of the Saimaa ringed seal

Abstract

The Saimaa ringed seal (Pusa hispida saimensis) is an endemic relict of the last ice age that inhabits a fragmented freshwater Lake Saimaa in Finland. This small seal population (current population size ca. 370-380 individuals) is one of the most endangered seals in the world. The high mortality rate of young seals due to by-catch mortality of fishing and insufficient snow conditions during breeding season are the most serious threats to the population. The fishing restrictions are the main short-term conservation measures of the Saimaa ringed seal. Springtime fishing restrictions have been set to reduce by-catch mortality of weaned pups. Certain fishing methods which can kill also adult seals, are totally forbidden in the main parts of the Saimaa ringed seal’s distribution area. The fishing restriction areas that covered about 13% of the Lake Saimaa in 2007, increased covering 61% of the lake in 2016. At the same time the seal population size has increased from around 260 to 360 individuals, and the annual pup production from ca. 50 pups to over 80 pups. Altogether, the fishing restrictions is the effective method to diminish mortality of especially juvenile Saimaa ringed seals. However, the pre-weaning pup mortality of the ringed seal has increased in 21st century due to poor snow conditions induced by climate change. Although the new methods to decrease the pre-weaning mortality are being developed and implemented in the current LIFE Saimaa seal project, global warming is a growing threat to the juvenile survival of the seal. Therefore, the fishing restrictions is the essential conservation method also in the future.