Phoca caspica)[1] is one of the smallest members of the earless seal family and unique in that it is found exclusively in the brackish Caspian Sea.

As the ice melts in the summer and warmer parts of the spring and autumn season, it also occurs in the deltas of the Volga and Ural Rivers, as well as the southern latitudes of the Caspian where the water is cooler due to greater depth.

Evidence suggests that the colonization events of Caspian seals were probably facilitated by river connections from the Arctic that have since disappeared, landlocking the populations sometime before the major Pleistocene glaciations.

In addition, the morphological structures in both species suggest they are descended from the ringed seal which migrated from larger bodies of water around two million years ago.

[citation needed] One notable attribute of Caspian seals is its adaptation to a wide range of air temperatures and given the extreme climate of its habitat.

In the first days of April, spring migration to the southern part of the Caspian Sea begins with mature female seals and their pups.

[6] In autumn and winter, Caspian seals prey mostly on sculpins, gobies, and crustaceans while inhabiting shallow waters in the northern part of the sea.

[7] Being one of the top predators in the ecosystem, Caspian seals had hazardous chemicals found inside their bodies such as heavy metals, organochlorine compounds, and radionuclides.

Caspian seals employ a capital breeding lactation strategy, where the mother will fast while nursing the pup, sometimes with a small amount of supplemental feeding.

[12] Several recent cases of large numbers of Caspian seals dying due to canine distemper virus have been reported, in 1997, 2000 and 2001.

Necropsies performed in June 2000 on eight Azerbaijan seals revealed microscopic lesions, including bronchointerstitial pneumonia, encephalitis, pancreatitis and lymphocytic depletion in lymphoid tissues.

The sequences were also identical to that of canine distemper virus found in the brain tissue of a seal that died in 1997 and showed no morbillivirus lesions.

This suggests persistence of canine distemper virus in the Caspian seal population over a span of several years or repeated spillover from the same terrestrial reservoir.

The study also asserts that the "unusually mild" winter that preceded the die-off in 2000 could have contributed to its cause "through increased ambient air pressure and accelerated disappearance of ice cover at the breeding areas in the northern Caspian Sea.

"[14] A century ago, their population was estimated at 1.5 million seals; in 2005, 104,000 remained, with an ongoing decline of 3–4% per year, primarily due to human influence (i.e. fisheries bycatch and habitat encroachment), outbreaks of Phocidae Distemper Virus (PDV), climate change, and pollution.

As of 2006[update], commercial icebreaker routes have passed through areas with high Caspian seal pup concentrations, which may contribute to loss of habitat.

According to the present studies, Kenderli Spit plays an important role for the seasonal migration of the Caspian seals and is recommended to be a protection area.