Ladoga ringed seal

The Ladoga ringed seal (Russian: Ладожская нерпа; Pusa hispida ladogensis) is a freshwater subspecies of the ringed seal (Pusa hispida) found entirely in Lake Ladoga in northwestern Russia. The Ladoga ringed seal was isolated in freshwater lakes and separated from the Arctic ringed seal as a result of the isostatic rebound of the region following the end of the Weichselian Glaciation.[1]

Ladoga ringed seal
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Clade: Pinnipedia
Family: Phocidae
Genus: Pusa
Species:
P. hispida
Subspecies:
P. h. ladogensis
Trinomial name
Pusa hispida ladogensis
(Nordquist, 1899)
Synonyms
Phoca hispida ladogensis

It is related to the even smaller population of Saimaa ringed seals in Lake Saimaa, a lake that flows into Ladoga through the Vuoksi River.

Appearance

The adult Ladoga seal grows to about 150 cm in length and weighs approximately 60–70 kg. Pups are approximately 50–60 cm at birth and weigh approximately 4–5 kg. There are four variations of coats.[2] About 47% of Ladoga seals have a dark brown coat with lighter ring shaped patterns, 29% have a dark brown coat with lighter vein-like patterns, and 17% have a light brown coat with a dark dorsal belt as well as faint rings and spots. The coats of the remaining 7% are not described by Popov. Annual molting takes place from April through June.

Reproduction

Females reach maturity at the age of four to five, and males at the age of six to seven. Pups are delivered in February through March, with weaning taking place after six to eight weeks. A normal lifespan is about 30–35 years.[3]

Conservation
A seal hunter from Sortavala at the shores of Lake Ladoga with his prey in 1940.

The current population is about 2,000–3,000, down from approximately 20,000 at the beginning of the 20th century, due to overhunting; hunting of the seals was banned entirely in 1980, but some illegal poaching still occurs.[4][5] The species' primary threats include entanglement in fisheries netting, industrialization in the areas surrounding Lake Ladoga, fuel spills from water vessels and the disturbance of their warm-weather sunning places by human recreational activities. The Ladoga seal is listed as an Appendix II species under the Bern Convention and also included in the Red Data Book of the Russian Federation.

See also
Wikispecies has information related to Pusa hispida.

Notes
  1. Davydova, Natalia N.; et al. (1996). "Late- and postglacial history of lakes of the Karelian Isthmus". Hydrobiologia. 322(1–3): 199–204. doi:10.1007/BF00031828. S2CID 9631019.
  2. Popov, L. "Ladoga Seal." Mammals in the Seas, volume II: pinniped species summaries and report on sirenians (FAO Fisheries Series) No. 5, Vol II, pp. 70–71
  3. Frost, K.J., Lowry, L.F. 1981. "Ringed, Baikal and Caspian seals, Phoca hispida Schreber, 1775, Phoca sibirica Gmelin, 1788, Phoca caspica Gmelin, 1788." Ridgway, S.H. and Harrison, R.J. (eds.): Handbook of Marine Mammals (Academic Press Inc., London) Vol. 2: Seals, pp. 29–53
  4. Chapskiy K.K. (1932) Ladozhskiy tyulen i vozmozhnost ego promyisla. – Otchet dlya Leningradskogo Issledovatelskogo instituta ryibolovstva: 147 – 157.
  5. Verevkin M.V. (2003) Rezultatyi aviaucheta kolchatoy nerpyi na Ladozhskom ozere Dinamika populyatsiy ohotnichih zhivotnyih severnoy Evropyi, materialyi III Mezhdunarodnogo simpoziuma, 16-20 July 2002, Sortavala, Republic of Karelia, Russia. - Petrozavodsk. – 2003: 202-204.

References
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