Ringed Seal
(Phoca hispida)
| Distribution and Numbers So named because of the ring-shaped marks on its coat, there are generally recognised to be five separate subspecies of the ice-inhabiting ringed seal, which some scientists refer to as Pusa hispida. The most numerous subspecies, P.h. hispida - referred to here as the Arctic ringed seal, is found in all of the Arctic Ocean seas and the Bering Sea, ranging as far south as Newfoundland and northern Norway. There is no up-to-date accurate estimate of Arctic ringed seal abundance due to its widespread and remote distribution. However a crude total estimate for all of the subspecies of 2.3-7 million was made in the late 1980s. |
| There are approximately 800,000 - 1,000,000 of the
subspecies P.h. ochotensis, referred to here as the Okhotsk ringed seal, distributed in the
Okhotsk Sea and northern Japan. There are also estimated to be about 5,500 Baltic ringed seals (P.h.
botnica) inhabiting the northern and central Baltic Sea, mostly in the Bothnian Bay.
Around 2,000 Ladoga seals (P.h. ladogensis) are found in Lake Ladoga in western Russia, while
only about 220-250 Saimaa seals (P.h. saimensis) remain in Lake Saimaa in eastern Finland. The retreat
of ice during the last glaciation caused the Baltic ringed seal to become separated from
the Arctic ringed seal about 11,000 years ago, and also caused the Saimaa and Ladoga seals
to be trapped in their respective freshwater lakes about 8,000-9,000 years ago. |
 P.h. botnica Photo: Anna Roos, Swedish Museum of Natural History |
| Status Arctic and Okhotsk Ringed Seals The effects of natural events and human-caused activities on these subspecies are difficult to determine due to the lack of accurate population data. There is concern however that oil and gas exploration and extraction in many parts of their respective ranges, particularly in the Chukchi and Beaufort Seas, may cause disturbance as well as possible pollution of the seals, their habitat and food supply. It has also recently been reported that the waters off Sakhalin Island in the Okhotsk Sea are about to be opened up to massive oil and gas development, and that tanker traffic and the extreme weather conditions in the area may lead to a major spill there. Potential disturbance and pollution from vessel traffic on the proposed Northern Sea Route is also a cause for concern. |
| Ringed seals are one of the most important subsistence prey for native hunters throughout their range, but it is difficult to determine the extent of this hunting. Available figures show however that the annual kill in Alaska was about 3,000 seals in the 1990s, 50,000 per year were killed in Canada in the 1970s and 1980s, 50,000 - 70,000 are killed each year in Greenland, and 7,300 were commercially hunted in Russia in 1988. It has been reported that Inuit natives from the Canadian territory of Nunavut, in a move towards commercial rather than subsistence hunting, are planning to undertake a hunt of up to 2,000 ringed seals a month, mostly for export to Japan, China and Taiwan. Plans have been announced to market sealskins as well as to process ringed seal meat into food products, organs and bones into health products, and to render fat into oil capsules for sale as a dietary supplement. A pilot hunt was planned for the summer of 1999, the seals being shipped to Newfoundland for processing until a plant could be built in the Arctic. In a related move it was reported that the Inuit Tapirisat of Canada and the Nunavut government are working together to overturn the section of the U.S. Marine Mammal Protection Act which bans the import of sealskins from Canada. Hunting may have an affect on the viability of local populations. |
| Arctic climate change may be affecting the seals' ice habitat, populations having been shown in the past to be very sensitive to changes in the ice conditions. Rising pollutant levels in ringed seals, even in the more northerly locations, have also recently been reported, indicative of a general rise in pollution of the marine environment on a global scale. Russia's Emergency Situations Ministry reported in December 1998 that leaking radioactive waste in the country's Arctic seas is resulting in excessive radiation levels, reaching 100 times normal levels in some places. The radioactive waste is held in Arctic dumps used by the Soviet Union in the 1960s. |
| Baltic Ringed Seal It is estimated that there were a minimum of 200,000 Baltic ringed seals at the start of the 20th century. Intensive hunting and pollution however have reduced their numbers considerably. Hunting reduced the population size to about 25,000 in the 1940s, while reproductive failure caused numbers to crash to about 10,000 in the 1970s. Hunting of the species was gradually limited in several countries, and then banned altogether throughout the Baltic Sea in 1988 by Recommendation 9/1 of the Helsinki Commission (HELCOM). Recently however there has been mounting pressure, especially from Finland and Sweden, for the Recommendation to be changed in order to re-allow hunting of the various seal species in the Baltic Sea, and there are concerns that this may lead to Baltic ringed seals being hunted once more. Scientific research published in 1997 calculated that the level of hunting that the Baltic ringed seal population could sustain was close to zero. Baltic ringed seal numbers are only now starting to recover gradually, and particular concerns are still being expressed regarding the viability of the Gulf of Finland population. |
| Toxic chemicals and metals in the heavily-polluted Baltic Sea have been blamed for pathological changes, disease and lowered reproductive capability in ringed seals. Although measures have been taken and this problem has been reduced to some extent, environmental contaminants remain a great threat to the health of the ringed seal population. Pollution-caused uterine occlusions, which severely reduce reproductive rates and which are probably caused by organochlorines such as PCBs, peaked at the end of the 1970s but are still quite common in the Bothnian Bay population. A significant percentage of females in the Bothnian Bay are sterile as a result. An unknown but considerable proportion of the small population in the Gulf of Finland died of drowning and suffocation in 1991-92. Although the most probable cause of this mortality was some form of neurotoxic compound, this has not yet been verified. Russia's Emergency Situations Ministry reported in December 1998 that chemical weapons dumps in the Baltic Sea are causing heavy metal and arsenic contamination. |
| Several tens of ringed seals, mostly young seals, die each year from entanglement in fishing nets and gear, while seal predation also causes some conflict between fishermen and seals. An additional threat to the population comes from the disturbance of ringed seal breeding sites by ship traffic through the ice. There is currently concern that the construction and development of oil and chemical terminals in the Gulf of Finland, along with increased vessel traffic in the area, may cause disturbance to the small ringed seal population there as well as increase the potential risk of oil spills and pollution. The Baltic ringed seal is listed as Vulnerable on the IUCN Red List and as an Appendix III species under the Bern Convention. The subspecies is also protected through legislation by various countries within its range. |
|
Ladoga Seal It is estimated that there were about 20,000 Ladoga seals at the start of the 20th century, but hunting up to the 1940s severely depleted the population. Hunting was banned in 1980 but illegal hunting and some killing of seals by fishermen still occurs. Since the 1950s the Ladoga seal has suffered from entanglement in fishing nets, 200-400 seals per year dying in this way in the early 1990s. Fishing effort in the lake has decreased at present, and the resultant bycatch of seals has probably also declined, although the actual bycatch figures are difficult to determine. The threat remains however of increased fisheries bycatch in the future. Recent studies by scientists have concluded that the pollution of Lake Ladoga, caused mainly by increased industrialisation around the Lake, is a serious threat, high levels of mercury being found in the seals and high levels of toxic chemicals in the water. |
| A serious threat to the population comes from disturbance caused by increasing recreational activities during the summer on the rocky islets in the northern parts of the lake, favourite haulout sites for the species. Increased vessel traffic is also a concern as it may result in disturbance and pollution, at least two large fuel spills occurring in 1997. The Ladoga seal is listed as Vulnerable on the IUCN Red List and as an Appendix II species under the Bern Convention. The species is also included in the Russian Red Data Book. |
| Saimaa Seal It is estimated that there were about 700 Saimaa seals at the beginning of the 20th century. Hunting subsequently killed many of the seals, and the subspecies was also eradicated from some parts of the lake by fishermen. In danger of extinction, the Saimaa seal was protected by Finnish law in 1955. However its numbers continued to decline rapidly, numbering as few as 180 by the early 1980s, before stabilising to some extent at current levels. The subspecies' high pup mortality was an important factor in the decline and it is thought probable that mercury pollution in the lake was also partly responsible. Hunting of the Saimaa seal is forbidden. |
| Lake Saimaa is characterised by several exposed water areas, connected to each other by narrow sounds. There are about 10 breeding areas and it is possible, because of the lake's sub-divided nature, that the population is divided into two or more sub-populations. Some seal sanctuaries have been set aside since 1982. Two national parks currently cover areas within the seals' range, while a national shoreline conservation programme is intending to establish extra protection for 6-8 of the breeding areas by the year 2006. Metsähallitus (the Finnish Forest and Park Service), the agency that is responsible for the monitoring and protection of the subspecies, is aiming to raise the number of Saimaa seals to a minimum of 400 by the year 2025. The population is currently slowly growing at about 2% per year due to protection measures. |
 P.h. saimensis Photo: Jouni Koskela, Finnish Forest and Park Service |
The most serious threat to the Saimaa seal is now from subsistence fishing, and there has been a significant mortality of seals, especially of juveniles, due to entanglement and drowning in fishing nets and traps. In an attempt to alleviate this problem, voluntary agreements now exist which forbid fishing around the main breeding sites from 15 April to 30 June, covering about 325km². This area covers approximately 50% of birth lair locations. The other main threats at present are house building along the shoreline, snowmobile traffic, and recreation around the lake which destroy suitable habitat for the subspecies and cause disturbance, particularly during the winter breeding season. Pollution of the lake by toxic chemicals and heavy metals has been a serious problem in the past, but lake pollution levels and concentrations of pollutants in Saimaa seal tissues have both decreased significantly in the last 15-20 years. |
| There have been problems in the past with Saimaa seal birth lairs
collapsing due to changes in the water level in winter, causing high pup mortality and
lowered weight of weaned pups. Until 1991 this was caused by regulation of the water for a
hydro-electric plant, but such artificial lowering of the lake's levels is not now
permitted during the period of permanent ice cover. Natural lowering of the lake's levels
occurs from time to time, but the effects of this have been reduced in recent years by the
artificial regulation of two lakes which empty into Lake Saimaa. The Saimaa seal is listed
as Endangered
on the IUCN Red List and as an Appendix II species under the Bern Convention. |
| Lifestyle Arctic and Okhotsk Ringed Seals The behaviour of these subspecies varies quite widely between regions. The seals however generally remain in contact with drifting pack ice or shorefast ice for most of the year and rest, pup and moult there. In autumn and early winter, as openings in the ice start freezing over, the seals create breathing holes in the ice. They continue to maintain these holes, sometime through ice up to 2m thick, with their strong claws. During winter and early spring the Arctic ringed seals dig caves or lairs into the drift snow that has gathered above the breathing holes, these often multi-chambered lairs offering protection from the extreme cold and polar bear predation. Seals typically maintain two or more lairs simultaneously, the distance between these lairs ranging up to 4.5km. |
| Pups are generally born in the lairs from mid-March to mid-April. They are born with a white coat which they shed within 4-6 weeks for a coat that is silver on the front, dark grey on the back, and with only a few spots. Nursing is thought to last 5-7 weeks, the nursing mothers occasionally foraging for food but still losing quite a lot of weight. Little is known about the subspecies' mating system, but mating is thought to take place in mid- to late May, presumably under the ice near the birth lair. Moulting generally takes place in mid-May to mid-July, the seals basking on the ice. Quite a lot of weight is lost by the moulting seals as they virtually stop feeding during this period. The adult coat varies widely but is generally dark grey to silver with numerous rings and spots, especially on the back. There has not been a great deal of research carried out into the Okhotsk ringed seal. However the subspecies is known to haul out sometimes on land and, unlike the other subspecies, it does not give birth in lairs. |
| Many seals are reported to migrate (e.g. north-south or inshore-offshore) on a seasonal basis in response to ice availability and there is evidence of long-distance migration and dispersion, particularly for juvenile seals. Arctic ringed seals, mostly pups and subadults, are the major prey of polar bears and arctic foxes. Other predators include wolverines, wolves, dogs, killer whales, walruses and large birds. Diet varies widely but the seals are known to eat cods, smelt, herring, crustaceans, zooplankton, squid and sculpins. |
| Baltic Ringed Seal Baltic ringed seals usually associate in small groups during the moult and during ice formation. Groups of ringed seals are found hauled out on rocks in the Gulf of Riga and the Gulf of Finland from May to November. During the winter however the seals are found alone, spread out in the ice fields, and are often aggressive to other individuals. Seals are also found alone, rather than in groups, during the ice-free period in the Bothnian Bay. The pups are born in lairs on the pack ice in late February - early March. Baltic ringed seals feed mainly on fish such as herring, smelt, whitefish, sculpin and perch. Crustaceans also form part of their diet and they feed heavily on these species, particularly isopods, during the winter. Peak moulting takes place from mid-April to the beginning of May. Sea eagles are known predators of Baltic ringed seal pups. |
| Ladoga Seal The Ladoga seal differs in appearance from the Baltic and Saimaa seals, being smaller, darker and having longer whiskers. During ice-free periods Ladoga seals gather together in herds on skerries and rocky island shorelines, the herds consisting of up to 300 seals. The seals use a rich repertoire of sound communication within these herds, both in air and underwater. The breeding behaviour of the Ladoga seal has not yet been documented, but it is thought that the pupping season lasts from March to the beginning of April. The birth lairs of the Ladoga seal are typically situated 40-60km from the shore, near hummocked or ridged ice, although in northern areas of the lake they are mostly found in snowdrifts along the shoreline. The pups are normally born with white coats, although some dark pups with black hairs in their coats have recently been observed. It is thought that lactation lasts 1.5-2 months and that mating takes place during early lactation. In the summer the seals concentrate in small areas in the northern part of the lake. Most of the seals have a dark brown coat, some with light rings and others with light vein-like patterns. Some seals however have a light coat with a black belt around the body and indistinct rings and brown spots. Ladoga seals feed mainly on prey such as smelt, vendace, ruffe and burbot. Lairs in the northern part of Lake Ladoga have sometimes been attacked by dogs, red foxes and wolves. |
| Saimaa Seal Saimaa seals are solitary animals and are usually found hauled out alone or in pairs along shorelines. The mating behaviour of the subspecies has not yet been documented, but the females are known to give birth to their grey-coated pups from late February to early March. The pups are born in lairs constructed in snow-drifts on the ice, the lairs having been built close to the shore of small islands and islets in late December. Pups are weaned after 7-9 weeks and start to look for their own food from mid-April to late June. Adult seals appear to remain in the vicinity of the same area year-round, often using the same shoreline or even the same rock. There is a great variety in coloration among Saimaa seals, but individuals are usually fairly dark. |
 P.h. saimensis Photo: Jouni Koskela, Finnish Forest and Park Service |
| Underwater visibility in Lake Saimaa is very poor due to high
concentrations of humus, in some areas visibility being as low as 2m, and the seals tend
to feed on fish in total darkness. The longest dive so far measured for a Saimaa seal has
been 23 minutes. Moulting takes place on land in late May - early June. Saimaa seals feed
on small schooling fish such as vendace, roach, smelt and perch. The subspecies has no
natural predators. |
| Statistics The measurements of Arctic and Okhotsk Ringed Seals vary greatly between regions and also during the year. Most adults measure 1.1-1.5m in length and 50-70kg in weight, males tending to be longer than females. Pups are born measuring 60-65cm in length and weighing 4.5-5.5kg. Females reach sexual maturity at 4-8 years, males at 5-7 years. Individuals have been known to live up to 43 years of age. |
| The Baltic Ringed Seal is the largest of the subspecies, adults weighing 110-124kg and measuring 1.5-1.75m in length. Females reach sexual maturity at 3-6 years, earlier than males. Baltic ringed seals have been known to live to 40 years of age. Adult Ladoga Seals weigh 32-56kg (47kg on average), while pups are born measuring 50-60cm in length and weighing 4-5kg. Females reach sexual maturity at 4-5 years, males at 6-7 years. Adult Saimaa Seals measure up to 1.5m in length and weigh 45-100kg (62kg on average). Males reach sexual maturity at 5-6 years, females probably one year earlier. About 50 Saimaa seal pups are born every year and little over half of them reach the age of sexual maturity. |
|
 |
