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Uploaded on Wednesday 09 Oct 2013 by GRID-Arendal

Historical decline of the Caspian seal (Pusa caspica)

Year: 2013 Author: GRID-Arendal
Description:
It is unclear how many seals remain in the Caspian Sea. From a population estimated at more than one million in the early years of the twentieth century, population estimates now vary between 110 000 and 350 000. For more than 100 years, hunting of seal pups was carried out in the frozen North Caspian area each winter. In the early twentieth century, nearly 100 000 seals were hunted each year; later a quota was set at 40,000 pups per year, further reduced to 20,000 pups per year. The hunting quota, set by the Caspian Bioresources Commission for 2007, was 18,000 seals. Even if during the last decade, no organized hunting has taken place in the North Caspian, the hunting quotas exceeded the estimated annual pup production (Härkönen et al 2008). Recent mass mortalities have reduced the seal population even further. In 2000, a mass mortality due to the canine distemper virus (CDV) caused tens of thousands of deaths throughout the Caspian (Azerbaijan, Kazakhstan, Russia, and Turkmenistan). Pollution has been shown to result in a high number of barren females (up to 70% of females are thought to be barren) which also threatens the overall seal population. Besides pollution and hunting, other stress factors impact on the Caspian seal population. A major food source for the seals is the small tulka fish, once abundant in the Caspian. Another factor which has become apparent in recent years is intrusion on to the ice during the pupping season and also the separation of mother seals from their pups (CEP 2007f). Active conservation efforts will be required to ensure that the Caspian seal does not become extinct. As a major mammal intimately involved in the food chain, it plays an important role in the biodiversity of the Caspian Sea and is a particular indicator of ecosystem health.
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