Ringed seal - WikiHQ

The ringed seal (Pusa hispida) is a small earless seal species found in Arctic and sub-Arctic regions. Its common name is derived from a distinctive patterning of dark spots surrounded by light gray rings.

The ringed seal is the most abundant and wide-ranging ice seal in the Northern Hemisphere; they can be found throughout the Arctic Ocean, into the Bering Sea and Okhotsk Sea as far south as the northern coast of Japan in the Pacific, and throughout the North Atlantic coasts of Greenland and Scandinavia as far south as Newfoundland. Two freshwater subspecies live in northern Europe.

Description

left|thumb|Back flippers

thumb|Photograph of head

The ringed seal is the smallest and most common seal in the Arctic, with a small head, short cat-like snout, and a plump body. Its coat is dark with silver rings on the back and sides and a silver belly, giving this seal its vernacular name. Depending on subspecies and condition, adult size can range from and adult weight can vary from . Its average length is about long, with an average weight of about . Currently, five distinct subspecies are recognized: P. h. hispida in the Arctic Ocean and Bering Sea, P. h. ochotensis in the Sea of Okhotsk, P. h. saimensis in Lake Saimaa in Finland, P. h. ladogensis in nearby Lake Ladoga in Russia and P. h. botnica in the Gulf of Bothnia. Together with the remaining northern latitude ice seals (ribbon seal, bearded seal, harp seal and hooded seal), these seals constitute the subfamily, Phocinae.) ||The Baltic Sea, especially in the Bothnian Bay where there is a large population, but there are also populations in the Gulf of Finland, the Gulf of Riga and the Archipelago Sea.

|120px|| Pusa hispida ladogensis<br/>(Ladoga ringed seal) ||Lake Ladoga

|120px|| Pusa hispida saimensis<br/>(Saimaa ringed seal) ||Lives only in Lake Saimaa in Finland and is one of the most threatened seals in the world, with a total population of approximately 500 individuals as of late 2024.

The three last subspecies are isolated from the others, like the closely related Baikal seal and Caspian seal.

Range and habitat

Ringed seals occur throughout the Arctic Ocean. They can be found in the Baltic Sea, the Bering Sea and the Hudson Bay. They prefer to rest on ice floe and will move farther north for denser ice.

Ringed seals reside in arctic waters and are commonly associated with ice floes and pack ice. While feeding, ringed seals dive to depths of . During the pupping season, Arctic fox and glaucous gulls take ringed seal pups born outside lairs while killer whales, Greenland sharks and occasionally Atlantic walruses prey upon them in the water.

Human interactions

thumb|Preparation of the ringed seal

thumb|Skin of the ringed seal.

Ringed seals have long been an important component of the diet of Arctic indigenous peoples throughout their range, and continue to be harvested annually by many communities.

In 2012 the Government of Nunavut warned pregnant women to avoid eating ringed seal liver due to elevated levels of mercury, although they stressed eating traditional "country food" is still healthy for adults.

Bycatch in fishing gear, such as commercial trawls, is a threat to ringed seals. Climate change is potentially the most serious threat to ringed seal populations since much of their habitat is dependent upon pack ice.

Climate change

Ringed seals reside within 35°N and the North Pole, and are thus known as a circumpolar based species. Climate change is projected to affect both polar regions more than anywhere else. This means a changing climate and life for all those residing in these polar regions. As for ringed seals, two potential outcomes lie ahead in this ever-changing climate.

Threats

In the past decade, the Arctic region has faced some of its highest temperatures within the instrumental record. Furthermore, within the past 2000 years, summer temperature highs have never been harsher, based on paleo-climate reconstructions. This warming is due to climate feedback mechanisms based on sea-ice melt. As sea ice melts, it frees up more open ocean water to be further heated, thus bringing about a positive feedback. Ocean water retains more heat than sea ice; additionally the albedo of sea ice is much higher than that of ocean water.

Ringed seals require sea ice to live and reproduce. They live most of their lives alone, only grouping together into colonies when they are on sea ice to molt, mate, or rest. Without access to sea ice, ringed seals are unable to sustain life, which further affects trophic levels both above and below.

Ringed seals are both predators and prey. A predator to zooplankton and fish, the ringed seal is considered a primary consumer as well as a secondary consumer. But the tertiary consumer, or top predator, in the Arctic is the polar bear, feeding mostly on seals, including the ringed seal. Yet through further exploration, the potential fates of this Arctic food web seem to be ambiguous, leading to a very important trade off of polar bear mortality and ringed seal sustenance.

Research

Most research on ringed seals is focused on their requirement of sea-ice to live and reproduce. With climate change projected to occur most dramatically at the poles, the Arctic is fated to extremely change, mainly with the melting of ice and changes in snowfall. Ferguson et al. studied ringed seal recruitment in western Hudson Bay with a focus on six environmental variables, including: snow depth, snowfall, rainfall, the temperature when pups were born, North Atlantic Oscillation (NAO) mechanisms, and lastly the spring break-up. The results of Ferguson et al. determined that decreases in snowfall had a negative effect on ringed seal recruitment, most likely from the occurrence of earlier break up of sea ice. The main process driving this break up is albedo, with less snowfall and more ocean exposed the ice melts more quickly. With seal pups being forced into the water sooner due to lack of ice, recruitment numbers dropped and resulted in a downward trend of the population. Ringed seals are not the only animals that require sea-ice in the Arctic and Sub-Arctic to thrive. Trophic levels come into play in terms of the food web and the reliance of one population on another or many others for survival. Most of this research is actually studied through simulations, since this requires future projections and interactions between many population, physical ocean, and biological mechanisms. Meier et al. studied current and future projections of climate in regards to sea-ice in the Baltic Sea by means of atmosphere-ocean models. Firstly, the ringed seal relies on sea-ice for breeding and is unable to breed on land, meaning, as ice melts away in the future, breeding grounds will become much scarcer. Only one bay, Bothnia Bay in the Baltic Sea, will be able to be used by ringed seals for breeding, vastly limiting their options. Ringed seals are only able to be successful with strained conditions in areas of 90%-100% ice cover probability. (Meier et al. 2004) The changes in ice scarcity projected for the future seem to greatly hinder the ability for ringed seals to reproduce in the Baltic Sea. Hoover et al. The lower ice coverage means more open water swimming for the ringed seals, which caused higher stress (cortisol) rates.

External links

Seal Conservation Society – Ringed Seal
SOS. Save our seals, thisisFINLAND
Inuit Tapiriit Kanatami page on the ringed seal
Pusa hispida - Animal Diversity Web
Smithsonian Institution - North American Mammals: Pusa hispida
Voices in the Sea - Sounds of the Ringed Seal