Caspian Seals (Pusa Caspica) are only found in the Caspian Sea and they are one of the smallest of the “true seals” or Phocids. The common ancestor to Caspian Seals were Ringed Seals though surprisingly their closest relatives are the much larger Grey Seals This bottom feeder can dive to depths of 500m and, as it is opportunistic, feeds on a varied diet of Gobies, Kilka, Silverside and shrimp. High levels of DDT and other pollutants have compromised these seals immune systems resulting in exaggerated levels of distemper related mortalities. Increased pollution levels in the region may also be affecting the fertility levels of females, with a study in the late 1980’s/ early 1990’s reporting a high level of them being barren.
CASPIAN SEALS BREEDING HABITS
99% of all Caspian Seal pups are born on the winter ice-field of the North Eastern Caspian sea.
Breeding occurs from late January through until mid March, while the peak birthing period occurs from late January to early/mid February. Females may give birth out in the open though they do prefer sites that provide shelter from the wind, such as up against a ledge or under an overhang. They do not make lairs as associated with Baikal or Ringed Seals.
Newborns have a long white coat which protects them from the cold. This coat is molted when the animal is around three weeks old. Mothers do leave their young to forage, though she does not remain gone for extended periods.
The weaning process takes on average just over a month. After this, when the ice begins to melt, the pup is self sufficient and is able to take to the water to fend for itself.
Polygyny is not observed in this species with males and females tending to form breeding pairs. Mating is thought to take place in the water.
After their annual molting period, which occurs in March-April, these seals will disperse to various foraging areas throughout the Caspian.
Pups weigh on average around 5kg at birth and measure +/- 70cm in length. Adult males and females tend to be of similar size to each other though weight fluctuates according to seasonal change. This can be anything from 35-50kg going right up to 55-80kg in Autumn.
As a direct result of unsustainable hunting, Caspian Seal populations have seen a dramatic decline over the last 150 years.
In 2008, their status on the IUCN’s Red Data list was changed from “Vulnerable” to “Endangered.” Despite their endangered listing, the Caspian Aquatic Bioresources Commission continues to exploit this species, with quotas of 18 000 being issued to Russia and Kazakhstan.
Entanglement poses a major problem to these seals. Aside from the legal hunting by Russia and illegal hunting by fishermen, it is estimated that around 12 thousand of these animals become entangled in nets and marine debris every year.
A postmortem on four animals, conducted in 1997 after a mass mortality was reported, found alarmingly high levels of DDT in their systems, as well as a previously unknown form of Canine Distemper Virus in one adult female. It is thought domestic dogs are responsible for the distemper.
Caspian Seal populations are dropping at a rate of around 5% per annum.