Pusa sibirica 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Carnivora Phocidae

Scientific Name: Pusa sibirica
Species Authority: (Gmelin, 1788)
Common Name(s):
English Baikal Seal
Taxonomic Notes: In the recent past the Baikal Seal has been classified within the genus Phoca. There is still some uncertainty regarding whether this species arose as a direct offshoot of the Arctic Ringed Seal, or whether it descended from a Paratethys Sea Phoca lineage. Rice (1998) classifies the Baikal Seal as belonging within Pusa, together with the Caspian Seal and the Arctic Ringed Seal.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Burkanov, V. (IUCN SSC Pinniped Specialist Group)
Reviewer(s): Kovacs, K. & Lowry, L. (Pinniped Red List Authority)
The current population size of the Baikal Seal is thought to be at the level of the Lake Baikal ecosystem capacity (80,000 – 100,000 individuals). If global warming continues the quality of habitat of the species will decline dramatically which may induce population decline. However, this species has survived periods of quite extreme warming in the region in the past and it is currently well monitored – such that declines should be detected rapidly when they occur. Thus, currently the Baikal Seal should be listed as Least Concern.

IUCN Evaluation of the Baikal Seal, Pusa sibirica
Prepared by the Pinniped Specialist Group

A. Population reduction Declines measured over the longer of 10 years or 3 generations
A1 CR > 90%; EN > 70%; VU > 50%
Al. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are clearly reversible AND understood AND have ceased, based on and specifying any of the following:
(a) direct observation
(b) an index of abundance appropriate to the taxon
(c) a decline in area of occupancy (AOO), extent of occurrence (EOO) and/or habitat quality
(d) actual or potential levels of exploitation
(e) effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.

Population abundance estimates based on direct pup counts at the end of breeding season and analysis of age and sex structure obtained from harvest suggest that at present the population is fluctuating at carrying capacity level for the Lake Baikal ecosystem. No reduction in abundance has been observed during last 30 years. Females mature at approximately age 3+, males at age 7+. Maximum longevity recorded is 56 years. Females produce pups throughout their life. Population abundance estimates conducted quite regularly over last 30 years.

A2, A3 & A4 CR > 80%; EN > 50%; VU > 30%
A2. Population reduction observed, estimated, inferred, or suspected in the past where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.

A decline in abundance for Baikal Seal has not been observed, estimated, inferred, or suspected in the past 30 years. Distemper virus killed about 6,500 Baikal seals in 1987-1988, but total abundance of the species did not change noticeably.

A3. Population reduction projected or suspected to be met in the future (up to a maximum of 100 years) based on (b) to (e) under A1.

A population reduction of Baikal Seal is possible in the future due to heavy pollutant burdens and illegal harvesting. Nevertheless, based on current conditions these two threats are unlikely to significantly impact the population in near future. It is unlikely to be occurred during next 30 years if these two threats will be at current level or lower. A population reduction for this species is suspected in the future due to global warming. It is likely that within next 30-40 years ice conditions in the lake will change dramatically and the Baikal Seal could be reduced in number by more than 30% which makes the species Vulnerable under this criterion (A3c).

A4. An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years) where the time period must include both the past and the future, and where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.

A population reduction of Baikal Seals has not been observed, estimated, inferred, or suspected in the past 50 years.

B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence (EOO): CR < 100 km²; EN < 5,000 km²; VU < 20,000 km²

The EOO of Baikal Seal is > 20,000 km².

B2. Area of occupancy (AOO): CR < 10 km²; EN < 500 km²; VU < 2,000 km²

The AOO of Baikal Seal is > 2,000 km².

AND at least 2 of the following:
(a) Severely fragmented, OR number of locations: CR = 1; EN < 5; VU < 10
(b) Continuing decline in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals.
(c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (iv) number of mature individuals.

C. Small population size and decline
Number of mature individuals: CR < 250; EN < 2,500; VU < 10,000

The abundance of Baikal seal is > 10,000.

AND either C1 or C2:
C1. An estimated continuing decline of at least: CR = 25% in 3 years or 1 generation; EN = 20% in 5 years or 2 generations; VU = 10% in 10 years or 3 generations (up to a max. of 100 years in future)
C2. A continuing decline AND (a) and/or (b):
(a i) Number of mature individuals in each subpopulation: CR < 50; EN < 250; VU < 1,000
(a ii) % individuals in one subpopulation: CR = 90–100%; EN = 95–100%; VU = 100%
(b) Extreme fluctuations in the number of mature individuals.

D. Very small or restricted population
Number of mature individuals: CR < 50; EN < 250; VU < 1,000 AND/OR restricted area of occupancy typically: AOO < 20 km² or number of locations < 5

The number of mature individuals of Baikal seal is > 1,000. AOO is > 20 km² and the number of locations is > 5.

E. Quantitative analysis
Indicating the probability of extinction in the wild to be: CR > 50% in 10 years or 3 generations (100 years max.); EN > 20% in 20 years or 5 generations (100 years max.); VU > 10% in 100 years

There is no any analysis conducted on probability of extinction Baikal Seal. Based on current status of the species it is unlikely that in can occurs within next 100 years.

Listing recommendationThe current population size of the Baikal Seal is thought to be at the level of the Lake Baikal ecosystem capacity (80,000 – 100,000 individuals). If global warming continues the quality of habitat of the species will decline dramatically which may induce population decline. However, this species has survived periods of quite extreme warming in the region in the past and it is currently well monitored – such that declines should be detected rapidly when they occur. Thus, currently the Baikal Seal should be listed as Least Concern.
Previously published Red List assessments:
1996 Lower Risk/near threatened (LR/nt)
1996 Lower Risk/near threatened (LR/nt)

Geographic Range [top]

Range Description: Baikal Seals are basically confined to Lake Baikal (31,570 sq. km), though they do travel short distances into rivers that flow into and out of the lake. An exception is one animal that was found 400 km downstream in the Angara River, the only river that flows out of the lake (Ivanov 1938, Pastukhov 1993, Rice 1998). Lake Baikal is located in southern Siberia, Russia, near the Mongolian border. The lake is 636 km long and at its maximum 79.5 km wide (Kutyrev et al. 2006).
Countries occurrence:
Russian Federation
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population increased from the 1970s through to the early 1990s to over 100,000 individuals (Petrov et al. 1997, Petrov 2002, 2003). Subsequently, population abundance declined slightly, probably due to commercial harvesting and the occurrence of canine distemper virus. The current abundance is estimated to be between 80,000 and 100,000 individuals (Petrov 2002, 2003) but this estimate may be biased based on survey errors of about 30% (Petrov et al. 1997) and short term abundance trends based on count data may merely reflect survey error variations. Baikal Seals are considered to be at the carrying capacity level of the Baikal Lake ecosystem.
Current Population Trend: Stable
Additional data:
Number of mature individuals: 80000-100000
Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: This species arrived in Lake Baikal approximately 400,000 years ago and is probably more closely related to the ringed seal than the Caspian seal (Pastukhov 1969a, Koyama et al. 1997, Sasaki et al. 2003). Baikal Seals are among the smallest of the pinnipeds, with adults reaching 1.1-1.4 m and weights of 50-130 kg. Pups are born at 3-3.5 kg and approximately 70 cm (Pastukhov 1971, Thomas et al. 1982). Adult males are slightly larger than adult females of the same age at physical maturity, when growth stops. Final body size is reached at approximately 15 years of age(Amano et al. 2000). Males reach sexual maturity at 7-10 years of age (Pastukhov 1993). Female Baikal seals become sexually mature between 3-7 years of age and some have their first pup by age 4, most by 5-6 years, with some not pupping until they are 9 years old (Pastukhov 1969b, Thomas et al. 1982). Baikal Seals continue to produce pups until they are 43-45 years old and may have the greatest longevity of any pinniped species. Approximately 10% of the population is older than 20 years of age, with records of adult females reaching 56 years of age and adult males 52 years of age (Pastukhov 1993, 1990).

The annual cycle of the Baikal Seal is driven more by ice than food (Ivanov 1938). In mid-October, the seals begin to move towards bays, lagoons and river deltas, mostly along the eastern shore where ice forms and expands out into the lake. They spend January to May spread throughout the lake, usually singly, in deep water in the central basins. Adults stay primarily in the north while immature seals are more often found in the southern part of Lake Baikal. Pups are born from late February to early April, with peak numbers born in mid March (Pastukhov 1990). Pups are born on the ice in dens which females actively build and maintain. During the pupping season, females are widely spread out on the ice. Their surface home ranges, including the den and breathing holes, are a minimum of 0.26 km² and do not overlap with other females (Ivanov 1938, Elagin et al. 1990, Pastukhov 1993, Martinkova et al. 2001). Pups do not usually enter the water for their first 2 -3 weeks.

Most pups are weaned in 2-2.5 months, although some are believed to be nursed for 3-3.5 months (Pastukhov 1971). Females move pups and construct new dens if the dens become damaged; this may be necessary to protect small pups from predators. Mating is believed to take place in April, approximately one month after the female gives birth (Pastukhov 1993). Although births take place throughout the lake, more pups (51%) are born in the northern one third of the lake, as compared to the central third (31%) or the southern third (17%) (Pastukhov 1971, Thomas et al. 1982, Petrov 1997).

The ice breaks up in May and June, a time when Baikal Seals undergo their annual moult. More than half of the population moves to the remaining ice in the northern and northeastern parts of Lake Baikal, forming aggregations that can be as large as 1,000-3,000 animals. Moulting takes approximately during a month-long period, during which Baikal Seals feed very little (Pastukhov 1993). Many Baikal Seals congregate in the southeastern part of the lake in the ice-free season to haul-out on rocky islands and shorelines between feeding excursions (Ivanov 1938, Pastukhov 1993, Petrov 1997). The eastern side of the lake is preferred because it has less human disturbance and greater biological productivity (Pastukhov 1993). It is not known whether Baikal Seals have a regular annual migration pattern. Satellite-tagging of four juvenile seals revealed that they moved throughout the lake in the course of a year, traveling from 400 to 1,600 km between September through May. Although it may not be typical of adult seals, the pattern of frequent diving and movement demonstrates that juveniles move considerable distances and spend little time hauled-out during the fall and winter months. Two of the four seals tagged in autumn returned to their tagging sites the following spring after wandering widely throughout the lake (Stewart et al. 1996). Diving patterns are not well documented; tagged juvenile Baikal Seals dove mostly to between 10-50 m, with some dives exceeding 300 m. the mean depth in Lake Baikal is 758 m (Kutyrev et al. 2006). Dive depths were shallower at night, consistent with the vertical movements of their preferred prey fish, the two species of golomyankas (Comeophorus spp.) which ascend from depths of 100 m or more during the day to forage at 10-25 m at night. Dive durations were generally 2-4 minutes, with 14-30% of dives lasting 6-10 minutes. The longest recorded dives exceeded 40 minutes and occurred during the winter in areas of heavy ice cover (Stewart et al. 1996). Baikal Seals feed on fish and 29 species have been recorded in their diet. Along with the two species of golomyankas mentioned above, they also consume two species of sculpin (Cottocomephorus spp.) as primary prey. Diversity of fish species consumed is highest in the summer with 17 species eaten, declining to eight species in fall, and only four principle species eaten in winter. Juveniles may also consume amphipods during winter (Ivanov 1938, Pastikhov 1967, Gurova and Pastukhov 1974, Thomas et al. 1982).
Systems: Terrestrial; Freshwater

Threats [top]

Major Threat(s): Subsistence hunting of Baikal Seal extends back to at least the Neolithic period (Khlobystin 1963, Weber et al. 1993). Commercial hunting began in the second half of the 18th century (Ivanov 1938, Pastukhov 1993), becoming a regular industry in the early in the 20th century. Annual harvests fluctuated between 2,000 and 9,000 seals in the early 20th century, then from under 1,000 to nearly 6,500 in the 1930s (Ivanov 1938). Harvests from 1977 to 1983 were consistently high. The official harvest quotas and catch level was about 6,000 plus an estimated “unofficial hunting” level of up to 3,600 seals (1984, Pastukhov 1993). In the late 1980s and early 1990s the official statistics were not reliable and did not reflect the actual harvest level. Estimates vary between 4,000 and 8,000 animals (Petrov et al. 1997) killed annually. Harvesting continues today. During 2004-2006 about 2,000 seals were reported killed in annual official statistics with estimations of an additional “uncounted” harvest of between 1,500 and 4,000 animals annually (Petrov 2007). The “uncounted” harvest includes wounded or drowned animals, incidental catch in fishing gear and poaching.

Baikal Seals are considered to be heavily contaminated with pollutants. Heavy organochlorine loads may make them vulnerable to its toxic effects (Nakata et al. 1997), such as possible suppression of the immune system (Tsydenova et al. 2003). Recent work shows that levels of some key organochlorines in Baikal Seals fell from 1992-2002. However, Baikal seal pups continue to carry higher DDT and PCB contaminant burdens than pups of other European and Arctic phocid species (Tsydenova et al. 2004). Adult Baikal seals are also known to carry high burdens of toxic PCB congeners. Chronic high levels of toxic PCB congeners at concentrations similar to those found in Baikal Seals have been linked to immunosuppression in harbor seals and may have contributed to the outbreak of morbillivirus epidemic that led to the mass mortality event in Europe in 1988. Extensive use and disposal of PCBs in the Baikal watershed is thought to be responsible for the current high levels of PCBs in Baikal seals (Nakata et al. 1997). Recent opening of Siberian oil fields and the completion of the Baikal-Amur railroad have spurred additional industrial development near Lake Baikal, posing unknown risks to the Baikal seal (Reijnders et al. 1993, Grachev 2002). An outbreak of a phocine distemper virus, a type of morbillivirus closely related to canine distemper virus (de Swart et al. 1995), killed approximately 6,500 Baikal Seals in 1987-1988 (Pronin and Kabanov 1992, Belykov et al. 1997). The virus in Baikal Seals differs from the strain of phocine distemper virus that killed Harbour Seals in European waters in 1988 and is believed to have been transmitted to seals from a terrestrial source, probably feral or domestic dogs (Barrett et al. 1992). Recent examination of Baikal Seals shows that the virus is still circulating in the population, although not as a highly infectious agent at this time (Mamaev et al. 1996). Natural predation does not appear to be a significant source of mortality for Baikal Seals, with only Brown Bears (Ursus arctos) mentioned as predators (Pastukhov 1993).

Conservation Actions [top]

Conservation Actions: Numerous measures, such as establishing commercial harvest quotas, changing methods and equipment used for harvesting seals and changing the timing of the hunt and the age class of seal that can be taken, have all been used during the history of the commercial harvest to regulate the catch (Svatosh 1923, 1925, Ivanov 1938, Pastukhov 1993, Petrov et al. 1997). Recent recommendations for the protection and conservation of the Baikal seal include several measures to reduce the impact of poaching by local residents (including increased penalties for illegal hunting) and mandatory reporting of incidental catch in fishing gear (Pastukhov 1993).

Citation: Burkanov, V. (IUCN SSC Pinniped Specialist Group). 2008. Pusa sibirica. The IUCN Red List of Threatened Species 2008: e.T41676A10506557. . Downloaded on 27 June 2016.
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