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Phoca largha

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA CARNIVORA PHOCIDAE

Scientific Name: Phoca largha
Species Authority: (Pallas, 1811)
Common Name(s):
English Spotted Seal, Larga Seal
Taxonomic Notes: Morphological, reproductive and behavioural differences separate Spotted Seals from their close relatives, the North Pacific Harbour Seals (P. v. richardii and P. v. stejnegeri) both of whose ranges overlap with the Spotted Seal (Rice 1998). Recent studies of mtDNA confirmed the distinctiveness of the Harbour and Spotted Seals at the species level. The two species have hybridized in captivity, although information on hybrids occurring in the wild is limited to one possible case (O’Corry-Crowe and Westlake 1997). While Shaughnessy and Fay (1977) identified several separate breeding concentrations, the limited samples examined to date do not show geographic substructure within the species (O’Corry-Crowe and Westlake 1997).

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Lowry, L. & Burkanov, V. (IUCN SSC Pinniped Specialist Group)
Reviewer(s): Kovacs, K. & Lowry, L. (Pinniped Red List Authority)
Justification:
The Spotted Seal is moderately abundant, but it faces numerous threats and several major subpopulations have declined in recent years. The global number of Spotted Seals is not known, nor is the extent of the current declines. Given the risk posed by climate change and the uncertainty regarding the status of this species – it should be classified as Data Deficient.

IUCN Evaluation of the Spotted Seal, Phoca largha
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.

Age-structure data are not available for the Spotted Seal population so the generation time cannot be calculated precisely. With sexual maturity attained at 3-5 years of age and a maximum longevity of approximately 35 years, the average age of reproducing individuals should be at least 10 years. A population reduction of Sotted Seals has not been observed, estimated, inferred, or suspected in the past 30 years. However, population abundance is poorly known and has not been monitored.

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 population reduction of spotted seals has not been observed, estimated, inferred, or suspected in the past 30 years.

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 Spotted Seals is suspected in the future because of predicted reduction in sea ice habitats due to continued climate warming. The likely amount of population reduction has not been projected, but could exceed 30% within the next 30 years. This meets the criterion for Vulnerable.

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 Spotted Seals has not been observed, estimated, inferred, or suspected in the past 30 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 Spotted Seals is > 20,000 km².

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

The AOO of Spotted Seals 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 current abundance of Spotted Seals is poorly known, but the number of mature individuals is certainly > 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
or
(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 current abundance of Spotted Seals is poorly known, but the number of mature individuals is certainly > 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 has been no quantitative analysis of the probability of extinction for Spotted Seals.

Listing recommendationPast, poorly documented, estimates of Spotted Seal abundance suggest a total population size of perhaps 400,000. Based on reports from coastal Alaskan hunters, Spotted Seals are still numerous and no major changes in abundance have been reported. However, climate warming and reduction in sea ice coverage are occurring, and because most Spotted Seals depend on sea ice for reproduction that will likely result in a population decline. Current abundance and population trend are unknown, and thus the Spotted Seal must be classified as Data Deficient at this time.
History:
1996 Lower Risk/least concern (Baillie and Groombridge 1996)

Geographic Range [top]

Range Description: Spotted seals are found in the Sea of Okhotsk and the Sea of Japan and reach China in the northern Yellow and Bohai Seas. They are widespread in the Bering and Chukchi Seas and range north into the Arctic Ocean to about the edge of the continental shelf, west to about 170°E longitude and east to the Mackenzie River Delta in Canada (Shaughnessey and Fay 1977, Quakenbush 1988). They inhabit the southern edge of the pack ice from winter to early summer. In late summer and fall, spotted seals move into coastal areas, including river mouths. They breed mostly on sea ice and haul-out on sea ice when it is available, but they also haul out on beaches and sandbars (Burns 1970, Lowry et al. 1998, 2000). There are several sites along Asian coast where spotted seal breed on small remote islands (e.g., in Peter the Great Gulf, the Kuril Islands, and small islands along east coast of Kamchatka) (Burkanov 1988, 1990, Trukhin and Katin 2001, Kostenko et al. 2004, Vertyankin and Nikulin 2004).
Countries:
Native:
Canada; China; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Russian Federation; United States
FAO Marine Fishing Areas:
Native:
Arctic Sea; Pacific – northeast; Pacific – northwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The abundance of spotted seals has never been well quantified. Poorly documented estimates suggest a total population size in the 1970s of perhaps 400,000, with 200-250,000 in the Bering-Chukchi Seas and perhaps 170,000 in the Okhotsk Sea (Bigg 1981, Quakenbush 1988). Mizuno et al. (2002) flew aerial line-transect surveys of a portion of the pack ice in the southern Okhotsk Sea in March 2000 and estimated there were 13,653 spotted seals in their 25,000 km² survey. There is no reliable estimate of the current total population size (Angliss and Outlaw 2007).

Female spotted seals become sexually mature at 3-4 years old and males at 4-5 years. Maximum longevity is at least 35 years (Quakenbush 1988).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Adult spotted seals are generally 1.5-1.7 m long and weigh 70-130 kg with little difference between the sexes (Bigg 1981).

In spring, spotted seals give birth to a single pup, mostly on the surface of sea ice but sometimes on land. Pups are born in a white lanugo coat that is shed at or before weaning which occurs about four weeks after birth. Mating occurs after pups are weaned. Spotted seals are annually monogamous and males defend lactating females on ice floes, and groups composed of a female with her pup and a male, called triads, are common during the breeding season (Quakenbush 1988).

In late-spring and summer many spotted seals leave the sea ice and haul-out on land to rest when they are not foraging. On some haulouts in Kamchatka the number of animals on shore may reach over 10,000 individuals (V. Burkanov pers. comm.). As sea ice reforms in October-November spotted seals again use the ice as their primary feeding and resting habitat (Burkanov 1990, Lowry et al. 1998, 2000). They are generalist feeders that take primarily a variety of fish species (walleye pollock, Arctic and saffron cod, rockfish, herring, sand lance, smelt, capelin, eelpout, salmonids and flounders), cephalopods (squid and octopus) and crustaceans (shrimp and crab) (Quakenbush 1988, Burkanov 1990).

Reported predators include Pacific sleeper sharks, killer whales, golden eagles, Steller’s sea eagles, ravens, gulls, polar and brown bears, wolves, Arctic foxes, walruses and Steller sea lions (Quakenbush 1988).
Systems: Terrestrial; Marine

Threats [top]

Major Threat(s): Subsistence hunting of spotted seals has no doubt occurred since humans first made contact with the species and they remain an important subsistence resource for coastal Natives in western Alaska (Quakenbush 1988). From the 1960s through the 1980s, the Soviet Union harvested several thousand spotted seals each year in both the Okhotsk and Bering seas, mostly from large commercial vessels (Heptner 1996). Commercial harvesting of this species no longer occurs in Russia.

Intensive harvesting of fish in the Okhotsk and Bering seas poses a risk to spotted seals as several of their main prey species are targets of commercial fisheries (Lowry and Frost 1985). Entanglement in commercial fisheries occurs occasionally in Japan and in the Sea of Okhotsk and Bering Sea and small organized control kills to limit damage to fisheries regularly occur in Japan (Mizuno et al. 2001, Angliss and Outlaw 2007). In Kamchatka, spotted seals sometimes eat fish out of fishing gear and fishermen shoot small numbers in local areas to defend their landings and protect their equipment (V. Burkanov pers. comm.).

Oil and gas development may cause disturbance to and adversely affect the habitat used by the spotted seals (Reijnders et al. 1993). Oil contamination poses poorly known risks to spotted seal populations. The greatest impacts would likely result if spills occurred during the pupping season, if food resources were negatively effected or if the spill was an event that affected a large area (St Aubin 1990). There is little information on contaminant burdens in this species, but concern would be greatest for animals living in the western part of the range where they occur near large population and industrial areas in China, Korea and Japan and in the Sea of Okhotsk.

Reduction in late winter and spring sea ice cover in the Sea of Okhotsk and the central and southern Bering Sea as a result of global climate change could be problematic for spotted seals as the majority of the population uses pack ice at the southern limit of the ice extent for pupping (Tynan and DeMaster 1997). Changes to ice characteristics that effect its location, timing, stability, etc. could result in lower survival of spotted seal pups. Disruption or alteration of the patterns of primary productivity and abundance of key prey species could also have detrimental effects on ice dependent seals like the spotted seal (Tynan and DeMaster 1997; Laidre et al., in press).

Conservation Actions [top]

Conservation Actions: In the United States the spotted seal is generally protected from all but subsistence hunting by Alaska Natives by the Marine Mammal Protection Act of 1972, which also generally prohibits import and export of parts or products from all marine mammals.

Commercial harvesting of spotted seals from vessels of the Russian Federation ended in 1994. Small scale commercial and subsistence harvest from small boats and land occurs along the Russian Far East coast, but the size of the harvest is relatively small (V. Burkanov pers. comm.).

Bibliography [top]

Angliss, R. P. and Outlaw, R. B. 2007. Alaska Marine Mammal Stock Assessments, 2006. U.S. Department of Commerce, NOAA Tech. Memo. NMFS-AFSC-168.

Bigg, M. A. 1981. Harbour seal Phoca vitulina Linneaus, 1758 and Phoca largha Pallas, 1811. In: S. H. Ridgway and R. Harrison (eds), Handbook of marine mammals, Vol. 2: Seals, pp. 1-27. Academic Press.

Burkanov, V. N. 1988. Modern status of marine mammal resources in Kamchatka. Razionaln. Ispol’zov. Bioresursov Kamchat: 138-176.

Burkanov, V. N. 1990. The spotted seals (Phoca largha) in the waters of Kamchatka and its impact on Pacific salmon. Thesis, Institute of Evolution, Morphology, and Biology of Animals.

Burns, J. J. 1970. Remarks on the distribution and natural history of pagophilic pinnipeds in the Bering and Chukchi seas. Journal of Mammalogy 51: 445-454.

Heptner, V. G., Chapskii, K. K., Arsen’ev, V. A. and Sokolov, V. E. 1996. Mammals of the Soviet Union. Smithsonian Institution Libraries and National Science Foundation.

Kostenko, V. A., Nesterenko, V. A. and Truhkin, A. M. 2004. Mammals of the Kuril Archipelago. Dalnauka, Vladivostok, Russia.

Laidre, K. L., Stirling, I., Lowry, L.F., Wiig, Ø., Heide-Jørgensen, M. P. and Ferguson, S.H. 2008. Quantifying the sensitivity of Arctic marine mammals to climate-induced habitat change. Ecological Applications 18 (Supplement: Arctic Marine Mammals): 97-125.

Lowry, L. F. and Frost, K. J. 1985. Biological interactions between marine mammals and commercial fisheries in the Bering Sea. In: J. R. Beddington, R. J. H. Beverton and D. Lavigne (eds), Marine Mammals and Fisheries, pp. 41-61. George Allen and Unwin, London, UK.

Lowry, L. F., Burkanov, V. N., Frost, K. J., Simpkins, M. A., Davis, R., DeMaster, D. P., Suydam, R. S. and Springer, A. 2000. Habitat use and habitat selection by spotted seals (Phoca largha) in the Bering Sea. Canadian Journal of Zoology 78: 1959-1971.

Mizuno, A. W., Suzuki, M. and Ohtaishi, N. 2001. Distribution of the spotted seal Phoca largha along the coast of Hokkaido, Japan. Mammal Study 26(2): 109-118.

Mizuno, A. W., Wada, A., Ishinazaka, T., Hattori, K., Watanabe, Y. and Ohtaishi, N. 2002. Distribution and abundance of spotted seals Phoca largha and ribbon seals Phoca fasciata in the southern Sea of Okhotsk. Ecological Research 17: 79-96.

O'Corry-Crowe, G. M. and Westlake, R. L. 1997. Molecular investigations od spotted seals (Phoca largha) and harbor seals (P. vitulina), and their relationship in areas of sympatry. In: A. E. Dizon, S. J. Chivers and W. F. Perrin (eds), Molecular genetics of marine mammals, pp. 291-304. The Society of Marine Mammalogy.

Quakenbush, L. T. 1988. Spotted seal. In: J. W. Lentfer (ed.), Selected marine mammals of Alaska: species accounts with research and management recommendations, pp. 107-124. U.S. Marine Mammal Commission, Washington, DC, USA.

Reijnders, P., Brasseur, S., van der Toorn, J., van der Wolf, P., Boyd, I., Harwood, J., Lavigne, D. and Lowry, L. 1993. Seals, fur seals, sea lions, and walrus. Status survey and conservation action plan. IUCN Seal Specialist Group.

Rice, D.W. 1998. Marine Mammals of the World. Systematics and Distribution. Society for Marine Mammalogy, Lawrence, Kansas.

Shaughnessy, P. D. and Fay, F. H. 1977. A review of the taxonomy and nomenclature of North Pacific harbour seals. Journal of Zoology (London) 182: 385-419.

St. Aubin, D. J. 1990. Physiologic and toxic effects on pinnipeds. In: J. R. Geraci and D. J. St. Aubin (eds), Sea mammals and oil: confronting the risks, pp. 103-127. Academic Press, New York, USA.

Tynan, C. T. and DeMaster, D. P. 1997. Observations and predictions of Arctic climate change potential effects of marine mammals. Arctic 50: 308-322.

Vertyankin, V. V. and Nikulin, V. S. 2004. The spotted seal of Utashud Ilsnad. Sokhran. Bioraznoobr. Kamchatki I Pril. More: 25-32.


Citation: Lowry, L. & Burkanov, V. (IUCN SSC Pinniped Specialist Group) 2008. Phoca largha. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 20 September 2014.
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