THE GREENLAND RIGHT WHALE

The Greenland right whale is a large baleen whale. It can be up to 18m in length and weigh up to 100 tonnes. The females are a little larger than the males. As opposed to other species of baleen whale, the Greenland right whale lives in the Arctic its whole life.

It lives in open seas, along the ice edge, but also far into the drift ice. It lives mostly on small crustaceans such as shrimp and krill (3-30mm in size). These are filtered out of the water with the help of the up to 5m long baleens. The Greenland right whale lacks a dorsal fin and has the blowhole high up on the head, something assumed to be an adaptation to living in tightly packed ice.

Greenland right whales are extremely fat with over 30 cm thick layers of blubber. They swim slowly compared with other species of whale. This made them an ideal prey for the early whalers. Because they swam slowly they were easy to approach in the boats of the day. They were so fat they floated when killed. Nearly everything is slow about these animals; they become sexually mature around the age of 25; they are fully grown at the age of 40-50, have a gestation period of around 14 months, have a calf every fourth year and can live to be over 200 years old. This makes them the longest lived species of animal that we know of.

THE RINGED SEAL

The ringed seal is the most abundant seal species in Svalbard. It can also be found in all areas of the Arctic, north right to the Pole. Ringed seals grow to about 130 cm; adult body mass varies widely with season, but most animals weigh between 50-100 kg. The sexes look quite similar except that adult males having a darker face during the breeding period.

Ringed seals can make breathing holes in the ice using the claws on their front flippers. This enables them to occupy areas deep into the fast-ice where no other seal species can penetrate. They excavate lairs in the snow over some of these breathing holes. Here, they haul-out and rest and the adult females give birth in such lairs in the spring. Most pups on Svalbard are born during the first week of April. The lair gives the pup protection against harsh weather conditions and to some degree also against predation. It takes some time for a polar bear or an arctic fox to dig through the lair roof, giving the seals a chance to escape to another lair or breathing hole. In Svalbard, ringed seals become sexually mature when they are about 4-5 years old, and the females can then produce one pup each year for the rest of their lives. Thus far the oldest ringed seal on record is a 45 year old male from Svalbard. Ringed seals are generally shallow divers that do not routinely dive deeper than 100m or for longer than about 10 minutes. However, maximum recorded dive performances from instrumented ringed seals from Svalbard are deeper than 500 m and over 45 min duration. Ringed seals feed on a variety of prey organisms, including both fish and invertebrates, but polar cod is by far the most important prey species. Ringed seals are the most important prey for polar bears, and the pups are important food for arctic foxes.

By Christian Lydersen