Pusa hispida

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA CARNIVORA PHOCIDAE

Scientific Name: Pusa hispida
Species Authority: (Schreber, 1775)
Common Name(s):
English Ringed Seal, Fjord Seal, Jar Seal
French PHOQUE ANNELÉ
Spanish FOCA OCELADA
Synonym(s):
Phoca hispida Schreber, 1775
Taxonomic Notes: There are five recognized subspecies: P. h. hispida, Arctic Ringed Seal; P. h. botnica, Baltic Sea Ringed Seal; P. h. ladogensis, Lake Ladoga Ringed Seal; P. h. saimensis, Lake Saimaa Ringed Seal, and P. h. ochotensis, Sea of Okhotsk Ringed Seal.

The Ringed Seal has been moved back and forth between the genus name Pusa and Phoca in recent decades. Current common usage generally follows Rice’s (1998) classification of Ringed Seals as Pusa, though this is certainly not universal.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Kovacs, K., Lowry, L. & Härkönen, T. (IUCN SSC Pinniped Specialist Group)
Reviewer(s): Kovacs, K. & Lowry, L. (Pinniped Red List Authority)
Justification:
P. h. hispida - Has a very large population size and broad distribution, however, there are future concerns for Arctic Ringed Seals with climate change impacts on Arctic sea ice; negative influences of climate change are already being documented in some parts of the subspecies range. Hence, this subspecies will need regular review.

P. h. botnica is currently showing an increase because of positive trends in one (its primary) breeding site, but there were recent-past population-wide declines, and current declines in some parts of its range. Additionally, climate change is likely to have a negative impact on this subspecies.

P. h. ladogensis has declined dramatically in recent decades. By-catch in fishing gear is the primary cause for the current declines, but climate change impacts are likely to be additive in the near future.

P. h. saimensis – The Saimaa Ringed Seal is a very small population that faces on-going threats from high mortality in fishing gear and virtually complete reproductive failure in recent years due to poor ice conditions within its limited range.

P. h. ochotensis – Ringed Seals in the Sea of Okhotsk have not been censused since the late 1960s. Population numbers and trends are unknown. Population work on this subspecies should be a high priority as climate change impacts are likely to have negative consequences for Ringed Seals in the Sea of Okhotsk.

For the global assessment at the species level, the Arctic Ringed Seals' numerous status and broad distribution leads to the classification of Least Concern for this species. However, given the risks posed by climate change to all Ringed Seal subspecies, including the Arctic Ringed Seals, this species should be reassessed within a decade.

Geographic Range [top]

Range Description:Ringed seals have a circumpolar distribution throughout the Arctic Basin including records of individuals near the North Pole (Rice 1998); arctic ringed seals also range widely into adjacent seas being found in the Bering Sea, Chukchi Sea, Beaufort Sea, Canadian Arctic Archipelago, Hudson Bay, Hudson Strait, Davis Strait, and Greenland, Barents, White, Kara, Laptev and East Siberian Seas, and they extend into some lake and river systems in Northern Canada (Heide-Jørgensen and Lydersen 1989). Separate populations occur in the Baltic Sea, Lake Ladoga in the Russian Federation, Lake Saimaa in Finland, and the Sea of Okhotsk south to northern Japan (Frost and Lowry 1981, Reeves 1998). Extralimital records for ringed seals extend far south on both sides of the Atlantic, to New Jersey in the west and Portugal in the east. In the Pacific vagrants have been recorded south to the Zhejiang in China and southern California (Rice 1998).
Countries:
Native:
Canada; Estonia; Finland; Greenland; Japan; Latvia; Norway; Russian Federation; Svalbard and Jan Mayen; Sweden; United States
Vagrant:
China; Denmark; Faroe Islands; France; Germany; Iceland; Lithuania; Poland; Portugal; United Kingdom
FAO Marine Fishing Areas:
Native:
Arctic Sea
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: P. h. hispida
The world-wide population size of arctic ringed seals is not accurately known. Citing many factors such as the vast geographic area occupied by the species, its highly variable distribution within areas that have been surveyed, the unknown relationship between the numbers of seals observed versus those not seen, and other factors, Frost and Lowry (1981) state that it is “unwise to attempt an estimate of the world population of this subspecies” (P. h. hispida). Despite numerous surveys at specific locales conducted since, Reeves (1998) believes that “this conclusion remains appropriate.”

Nevertheless, published world-wide population estimates exist including 6-7 million (Stirling and Calvert 1979) and 2.5 million (Miyazaki 2002). Some recent survey and pup production data are available from parts of the arctic ringed seal’s range (e.g. Frost and Lowry 2004, Bengtson et al. 2005, Moulton et al. 2005, Krafft et al. 2006), but these data are limited in spatial scope. Little information is available from large parts of the ringed seal’s arctic range, such as the eastern parts of the Russian Federation (but see Ognetov 1993). Decreased pup production and survival have recently been documented in some areas that have been attributed to climate change (e.g. Ferguson et al. 2005, Stirling 2005).

P. h. botnica
During the past century Baltic ringed seals declined precipitously from 190,000-220,000 to approximately 5,000 by the late 1970s (Harding and Härkönen 1999). The principle reason for the decline was over-harvesting, but low fertility caused by organochlorines and other contaminants may also have inhibited natural population growth during the decades following protection. The population of P. h. botnica was estimated to be between 5,000 and 8,000 individuals in the late 1990s; during 1998-2006 the number of ringed seals in Bothnia Bay, where about 75% of the population resides, has increased at a rate of 4.3 % per year (Karlsson et al. 2007). However, in the Gulf of Riga it is thought that the 1,400 seals counted in 1996 have been experiencing a steady decline since that time. The small subpopulation in the Gulf of Finland (~300 animals) has showed no increase since 1994. Current sea ice trends in the Baltic and future projections for the next 30 years pose a major threat to all southern populations in the Baltic; only the Bay of Bothnia is likely to retain fairly good winter sea-ice habitat for ringed seals (Meier et al. 2004).

P. h. ladogensis
The size of the P. h. ladogensis population was thought to be about 20,000 at the start of the 20th century, but bounties were paid to reduce the population and by the 1970s there were approximately 10,000 animals remaining (Agafonova et al. 2007). In 2001, the aerial survey of the basking population counted 2,000 (+-70) individuals on the ice (Verevkin 2002), which suggests a total population size of 3,000 to 5,000 seals (Agafonova et al. 2007).

By-catch in fishing gear is the major source of mortality in this population. Deaths due to this source alone account for 10-16% of the population annually (Verevkin et al. 2006), which is clearly unsustainable. The Ladoga ringed seal is listed in the Red Data Book of the Russian Federation.

P. h. saimensis
The number of P. h. saimensis in Lake Saimaa fell below 200 individuals in the early 1980s (Sipilä and Hyvärinen 1998). Thereafter, for a short period the population was increasing (to 240 in 2000, Sipilä 2003, Auvinen et al. 2005), reaching a maximum estimate of 280 in 2005 individuals for a brief time (Sipilä and Kokkonen 2008). A population viability analysis conducted by Ranta and Lundberg (2006, unpublished) suggested a potential for optimism regarding the survival of this population, as did projections in Sipilä (2006). But climate change impacts on Saimaa seal habitat were not incorporated into these predictions (Sipilä and Kokkonen 2008), nor was much attention paid to the fact that the population within the lake system is geographically subdivided (Sipilä at al. 2005), and the subdivision could markedly increase the future rate of inbreeding (Palo et al. 2003). Currently, mortality induced by fisheries by-catch is significant (Kokko et al. 1998, Sipilä and Hyvärinen 1998, Sipilä 2003). This mortality source, in addition to very high pup mortality during 2005-2007, is expected to cause this population to once again decline (Sipilä and Kokkonen 2008).

P. h. ochotensis
In the Sea of Okhotsk estimates for ringed seal abundance in 1968 and 1969 were 818,000 and 865,000 respectively (Reeves 1998). The population of P. h. ochotensis was estimated to be 800,000-1,000,000 by Miyazaki (2002). However, in reality no recent data are available and current population trends are unknown.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Arctic ringed seals are in many respects the “classic” ice-seal. The subspecies P. h. hispida and P. h. ochotensis use sea ice exclusively as their breeding, moulting and resting (haulout) habitat, rarely if ever coming onto land (Smith and Stirling 1975, Frost and Lowry 1981, Kelly 1988). Their ability to create and maintain breathing holes in sea ice using the well-developed claws on their fore-flippers allows them to thrive in areas where even other ice-associated seals cannot reside. Although ringed seals are quite small they deal with the thermal challenges posed by the arctic winter by having a very thick blubber layer, and by building lairs (small caves) in the snow on top of sea ice during the winter. The lairs are particularly important for neonatal survival (e.g., Lydersen and Smith 1989). Each seal builds several lairs so that they can escape if a predator attacks one of their structures; ringed seals have co-evolved with their principal predator, the polar bear (Ursus maritimus) over the last tens of thousands of years (Stirling and Øritsland 1995). Arctic foxes (Alopex lagopus) are also an important predator in some coastal areas (Smith 1976, Lydersen 1998). In addition to the constructed holes and lairs, ringed seals also use natural cracks along pressure ridges and leads in the sea ice for breathing.

Reported mean age at sexual maturity (MAM) for ringed seals females varies in the literature from 3.5 – 7.1 years (Holst and Stirling 2002, Krafft et al. 2006). Males likely do not participate in breeding before they are 8 and 10 years old. The average size of adults 10 years and older varies between locations and different age cohorts, but averages of 115-136 cm in length and 40-65 kg in weight have been reported, with males being slightly larger than females (Smith 1973, Frost and Lowry 1981, Smith 1987, Lydersen and Gjertz 1987). Ringed seals are long lived, with ages close to 50 reported (e.g. Lydersen and Gjertz 1987). Reproductive rates of adult female ringed seals vary between 0.45-0.86 (see Reeves 1998), with a maximum of 0.91 (Lydersen and Gjertz 1987). Regional production rates are variable; reproductive success depends on many factors including prey availability, the relative stability of the ice, sufficient snow accumulation prior to the commencement of breeding, etc. (e.g., Lukin 1980, Kelly 1988, Smith 1987, Lydersen 1995).

A single pup, weighing 4.0-4.5 kg, is born in the spring (March to May), with most pups being born in early April (Frost and Lowry 1981). In Lake Saimaa and in the southern part of Baltic Sea pups are born somewhat earlier, in late February or early March (Pälsi 1924, Sipilä 2003). Births occur in subnivean lairs excavated in snow that accumulates upwind and downwind of ice ridges (Smith and Stirling 1975, Furgal et al. 1996), or in cavities occurring between blocks of ice in pressure ridges (McLaren 1958, Kelly 1988). Lairs provide thermal protection against cold air temperatures and high wind chill and afford at least some protection from foxes and polar bears (Smith 1976, 1980, Smith and Stirling 1975, Gjertz and Lydersen 1986). A female will move a young pup between lairs within her complex of lairs (usually 4-6 per female) if one lair is attacked by a predator; older pups are able to shift between structures independently as they develop swimming skills in the first weeks of life (Lydersen and Hammill 1993a,b). Lactation lasts an average of 39 days and pups are weaned at approximately 20 kg (Lydersen and Kovacs 1999). Females mate towards the end of the lactation period, similar to other phocid seals. Shore-fast ice is considered to be the most important habitat for pupping, although the importance of pack ice is not well known; this habitat is used at least in the Davis Strait and in the Barents Sea (e.g. Wiig et al. 1999).

Ringed seals moult from around mid-May to mid-July when they spend quite a bit of time hauled out on ice at the edge of the permanent pack ice, or on remnant land-fast ice along coastlines (Reeves 1998). Feeding intensity is at a minimum at this time (Ryg et al. 1990).

Outside the breeding and moulting seasons, arctic ringed seals are distributed in waters of nearly any depth; their distribution is strongly correlated with seasonally and permanently ice-covered waters and food availability (e.g. Simpkins et al. 2003, Freitas et al. 2008).

Many studies of the diet of arctic ringed seal diet have been conducted and although there is considerable variation in the diet regionally, several patterns emerge. Most ringed seal prey is small, and preferred prey tends to be schooling species that form dense aggregations. Fishes are usually in the 5-10 cm range and crustacean prey in the 2-6 cm range. Typically, a variety of 10-15 prey species are found with no more than 2-4 dominant prey species for any given area. Fishes are generally more commonly eaten than invertebrate prey, but diet is determined to some extent by availability of various types of prey during particular seasons as well as preference, which in part is guided by energy content of various available prey (Reeves 1998, Wathne et al. 2000). Polar cod (Boreogadus saida) is often reported to be the most important prey species for ringed seals (see Labansen et al. 2007 for review). Young polar cod (≤2 yrs) are often found closely associated with sea ice, living under and even in spaces within sea ice (Falk-Petersen et al. 1986). Ringed seals also eat a variety of other members of the cod family, including arctic cod (Arctogadus glacialis; Holst et al. 2001), and saffron cod (Eleginus gracilis) with the latter being particularly important during the summer months in Alaskan waters (Lowry et al. 1980). Redfish (Sebastes spp.), capelin (Mallotus villosus) and herring (Clupea harengu) are also important in the diet of arctic ringed seals in some regions. Invertebrate prey seems to become more important to ringed seals in the open-water season and often dominates the diet of young animals (e.g. Lowry et al. 1980, Holst et al. 2001). Large amphipods (e.g. Themisto libellula), krill (e.g. Thysanoessa inermis) mysids (e.g. Mysis oculata), shrimps (e.g. Pandalus spp., Eualus spp., Lebbeus polaris, Crangon septemspinosa) and cephalopods (e.g. Gonatus spp.) are all eaten by ringed seals and can be very important in some regions at least seasonally.

Ringed seals in the Baltic sea as well as in Lakes Saimaa and Ladoga use ice for breeding and moulting, but are forced to haul out on islands and shorelines during the summer season when ice is not available. Their general season patterns are similar to those of arctic dwelling ringed seals. One notable difference in social structure is that Ladoga ringed seals form large herds during the open water period; this behaviour of mass haulouts is concentrated in the Valamm Nature Park (Agafonova et al. 2007).

Saimaa and Ladoga ringed seals are confined to freshwater lakes where they prey on a wide variety of fish and some invertebrates, especially smelt (Osmerus eperlanus), vendace (Coregonus albula), burbot (Lota lota), perch (Perca fluviatalis), roach (Rutilus rutilus), whitefish (Coreogonus lavaretus) and other fishes in small quantities (Sipilä and Hyvärinen 1998, Agafonova et al. 2007).
Systems: Terrestrial; Freshwater; Marine

Threats [top]

Major Threat(s): Humans have hunted ringed seals in the Arctic since the arrival of people to the region millennia ago (e.g. Murdoch 1893, Riewe and Amsden 1979). They are a fundamental subsistence food item for most coastally dwelling northern peoples. Reeves (1998) reported an annual quota for shore-based hunters in the Sea of Okhotsk of 7,500 and a combined estimate of 10,000 taken per year from the Bering, Chukchi, and Western Beaufort Sea by Russians and Native Alaskans. Further, Reeves (1998) estimates that the annual removal of ringed seals in the Canadian Arctic is in the “high tens of thousands” at present, and that in 1980s, including animals killed and lost, the harvest was between 60,000 and 80,000, and may have exceeded 100,000 in some years. Another substantial annual harvest occurs in Greenland with nearly 100,000 taken per year in the 1970s and approximately 70,000 taken annually in the early 1990s (Teilmann and Kapel 1998).

Commercial harvests of ringed seals in the early to mid-20th century at southern latitudes were sometimes large and probably had significant local impacts on the respective populations. Annual harvests of 72,000 from 1955 to 1965 in the Sea of Okhotsk, 20,000 in the Baltic Sea, as well as commercial harvests in Lakes Ladoga and Saimaa (Reeves 1998, Sipilä and Hyvärinen 1998) all provide examples of the negative effect of localized over-harvesting on ringed seal populations. Kokko et al. (1997) have suggested that the sustainable harvest level for Baltic ringed seals at the end of the 1990s was close to zero (Kokko et al. 1997). Harvest statistics reported for Western Russia by Belikov and Boltunov (1998) suggest that maximum catches earlier in this century exceeded the total allowable catches (TACs) significantly, with harvests of up to 8,900 in the White Sea (1912), 13,200 in the Russian Barents Sea (1962), and 13,200 in the Kara Sea (1933). These harvests are thought to have dropped considerably in recent decades, though there are no available data. Reporting of harvest statistics and enforcement of TACs is difficult to manage in outlying areas, and the harvest of ringed seals in eastern Russia is largely unknown.

Ringed seals carry loads of organochlorine and heavy metal contaminants from human industry and agriculture which have been implicated in uterine pathology in Baltic seals (Bergman and Olsson 1986), and high concentrations of mercury in Saimaa seals is thought to have reduced pup production in the 1960s and 1970s (Sipilä and Hyvärinen 1998, Kostamo et al. 2002). However, following restrictions on the use and release of persistent organic pollutants (POPs) into the environment, levels are dropping rapidly in the Baltic (e.g. Kostamo et al. 2002). The same is true with regards to POPs in Arctic populations (e.g. Wolkers et al. 2008). Oil contamination poses poorly known risks to ringed seal populations. The greatest impacts would likely result if spills occurred during the pupping season or if food resources were negatively effected (Smith 1987, Reeves 1998).

Manipulation of water levels, recreational snow machine operation, net-fishing, boating, tourism and development of cottages on the shoreline at Lake Saimaa have been noted as threats to the ringed seals in Lake Saimaa, and industrial pollution, net fishing and poaching, as well as disturbance of on-shore summer haulout groups have been highlighted as threats for the Lake Ladoga ringed seals (Sipilä and Hyvärinen 1998, Agafonova et al. 2007). Predation by red fox (Vulpes vulpes), wolves (Canis lupus), feral and domestic dogs and even birds of prey are also risks for these lake seals (e.g. Kunnasranta et al. 2001). By-catch in fisheries and other negative impacts associated with fisheries conflicts seem at present to be the major threat to the two subspecies of ringed seals occupying Lakes Saimaa and Ladoga (Kokko et al. 1998, Sipilä and Hyvärinen 1998, Verevkin 2002, Sipilä 2003, Agafonova et al. 2007).

Global warming may pose the greatest threat to ringed seals in all subspecies if it leads to large losses of the stable ice habitat required by ringed seals for pupping and rearing their young (Tynan and DeMaster 1997, Learmonth et al. 2006, Kovacs and Lydersen 2008, also see Laidre et al. 2008). Early break-up of the ice results in poor condition of pups and higher mortality rates (e.g. Smith and Harwood 2001). Associated changes in precipitation and weather patterns could also negatively effect ringed seal populations if there is insufficient snow cover to protect pups in lairs in the spring (Stirling and Derocher 1993; Ferguson et al. 2005). Pups born outside lairs have a very low chance of survival; the pups are so small that even large gulls can be predators if they are exposed (e.g. Lydersen and Smith 1989). Declining trends in reproduction and survival of pups have already been noted in some regions that have been attributed to earlier break-up of the sea ice over recent decades and concomitant changes in the marine ecosystem (Ferguson et al. 2005, Stirling 2005).

Ice is also needed by ringed seals for moulting, resting, and in some populations foraging, but the type of ice and its stability is more flexible outside the breeding season, though northern ringed seals still exhibit a clear preference for areas with considerable ice coverage (Simpkins et al. 2003, Freitas et al. 2008). Reductions in arctic sea ice could have quite dramatic effects via prey availability if polar and arctic cod populations are negatively impacted. Climate change impacts could be particularly acute for ringed seals living in restricted habitats such as the Ladoga and Saimaa Lake populations (Learmonth et al., 2006), and possibly also for ringed seals in the Okhotsk and Baltic Seas (see Meier et al. 2004). In Lake Saimaa there was an abnormally high lair mortality of pups in 2006 and 2007 because of poor ice and snow conditions (Sipilä et al. 2007).

Reductions in sea ice cover will likely lead to increased human activity in the Arctic in the form of shipping and resource extraction industries, with associated increased threat of marine accidents and pollution discharge (Pagnan 2000). An increase in human created noise in the arctic environment could cause marine mammals, including ringed seals, to abandon areas (Tynan and DeMaster 1997). Disturbance seems to be disruptive to haulout groups in Lake Ladoga during summer and routine day-tourism seems to have caused the desertion of at least two previously used sites (Agafonova et al. 2007, Verevkin et al. 2007). However, it must be noted that Moulton et al. (2002, 2003, 2005) found no more than slight effects on ringed seals from construction, drilling and operation of the Northstar offshore island oil production facility in the Beaufort Sea, and other assessments of industrial activities in the Arctic suggest relatively minor impacts on ringed seals (Kelly et al. 1988, Davis et al. 1991, Blackwell et al. 2004), though over-flights by aircraft certainly cause disturbance to ringed seals if flights occur by helicopter at less than 1,500 m and by fixed-winged aircraft at closer than 500 m (Born et al. 1999).

Conservation Actions [top]

Conservation Actions: Ringed seals are protected by a variety of laws and quotas in different parts of their range, but even within Europe the legal provisions are not always being fully implemented in domestic law (Wilson et al. 2001). The population in Lake Saimaa has been protected since 1955, and additional protection has been afforded via the establishment of two national parks within the lake, and regulation of shoreline development. Similarly, the hunting of seals in Lake Ladoga was prohibited in 1980 (Sipilä and Hyvärinen 1998). In the United States the Marine Mammal Protection Act of 1972 allows ringed seals to be harvested only by Alaskan Native hunters for subsistence purposes, and that Act generally prohibits all other forms of taking except where specifically permitted (Angliss and Outlaw 2005). State Nature Reserves at Franz Josef Land and in the White and Kara seas protect large areas of ringed seal habitat in the western Russian Arctic (Belikov and Boltunov 1998). Quotas and licensing of hunting have been in place in various parts of the Russian Federation for decades (Belikov and Boltunov 1998), though this has done little to stop the decline of ringed seals in Lake Ladoga. Baltic ringed seals were protected from all killing by the Soviet Union in 1980, by Sweden in 1986, and by Finland in 1988 (Härkönen et al. 1998).

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Citation: Kovacs, K., Lowry, L. & Härkönen, T. (IUCN SSC Pinniped Specialist Group) 2008. Pusa hispida. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 22 September 2014.
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