0000000000350815
AUTHOR
Miina Auttila
Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)
The Saimaa ringed seal (Pusa hispida saimensis) is one of the few freshwater seal populations worldwide. The major conservation issue of this critically endangered population is bycatch mortality. We used digestive tract content and stable isotopes (d13C and d15N) to estimate the diet and seasonal feeding patterns for gaining better understanding of the seals feeding habits and potential conservation implications. The diet was similar across age groups. Altogether 15 fish species were identified and the most important were smelt (Osmerus eperlanus), ruff (Gymnocephalus cernuus), perch (Perca fluviatilis), vendace (Coregonus albula) and cyprinids. The high d15N values suggested that the seal…
Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)
The Saimaa ringed seal (Pusa hispida saimensis) is one of the few freshwater seal populations worldwide. The major conservation issue of this critically endangered population is bycatch mortality. We used digestive tract content and stable isotopes (d 13 Ca ndd 15 N) to estimate the diet and seasonal feeding patterns for gaining better understanding of the seals feeding habits and potential conservation implications. The diet was similar across age groups. Altogether 15 fish species were identified and the most important were smelt (Osmerus eperlanus), ruff (Gymnocephalus cernuus), perch (Perca fluviatilis), vendace (Coregonus albula )a nd cyprinids. The high d 15 N values suggested that th…
Accurate spatial ecology of endangered Saimaa ringed seals as a base for fishing closure determination
Saimaa ringed seal (Phoca hispida saimensis) is an endangered subspecies living landlocked in Lake Saimaa, southeastern Finland. One of the major threats of this small population (ca 370 seals) is by-catch due to mainly recreational gill net fishing. For mitigating by-catch mortality varied fishing closures and restrictions have been established in the lake over time. The fishing restrictions cover year round ban of the most dangerous fishing methods and springtime (15.4.-30.6.) gill net ban to protect especially the pups. In this study, we describe the usage of accurate spatial ecology data of the Saimaa ringed seals as a base for conservation measures. Telemetry tracking data of both; juv…
Project LIFE Saimaa Seal - Safeguarding the Saimaa ringed seal
The Saimaa ringed seal (Pusa hispida saimensis) is one of the most endangered and rarest seals in the world. The current population size is ca. 370 individuals, and the Saimaa seal is the only endemic mammal in Finland. The national conservation strategy and action plan for the Saimaa ringed seal was adopted in 2011 to improve the conservation status of the species. Even though the previous conservation efforts have been successful the seal still is endangered. The current seal population might overcome detrimental effects of a singular threat, but the combined effects of different threats may still be fatal to the population. The ongoing project LIFE Saimaa seal (duration 2013-2018) was ta…
Fishing restrictions is the essential protection method of the Saimaa ringed seal
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 se…
Improving the accuracy of estimations on natality and pre-weaning pup mortality of the endangered Saimaa ringed seal
The Saimaa ringed seal (Phoca hispida saimensis) is the only endemic mammal in Finland. It inhabits fresh water Lake Saimaa, and its population size is around 370 individuals with 60-80 pups born annually. One of the most critical threats for the population is climate change. The ringed seal is dependent on sufficient ice and snow cover for a breeding habitat, and mild winters have a negative effect on pup survival. In addition, the reliability of the population estimates, which are based on annual lair censuses, suffers when there is no sufficient snow cover for subnivean lairs or when the lairs are not detectable during the census due to early melting. For improving the seal stock monitor…