Newfoundland Seals

Swiling, An Industry of Yesteryear

In 1850, "swiling", the annual Newfoundland sealing industry, was worth between $1.0 and $1.25 million, rising to $10 to $12 million by 1982, from the sale of fur, leather, meat (carcasses and flippers), and oil valued as fuel for lamps, cooking oil, and lubricant. In 1983, a European Communities Directive prohibiting seal imports reduced the hunt to a minor sport carried out by local coastal landsmen.

Seals are pinnipeds of the scientific suborder Pinnipedia. They are "fin-footed" marine mammals that have evolved from earlier land animals. There are three families of living pinnipeds, the Otaridae ("eared seals" and sea lions of the Pacific coast), the Phocidae (hairy or "true seals"), and the Odobenidae (walrus).

"True seals" are distinguished from the "eared seals" by having no visible ears, and by the shape of the body and limbs. "Eared seals" are able to walk on land while "true seals" are further evolved for an aquatic life, and move on land only by undulating body motions. Included in the "true seals" are elephant seals, monk seals found in Hawaii and the Mediterranean Sea, the harbor seal, and several species of ice seals including those on the Atlantic coast of Canada, and Newfoundland, described below.

ADAPTED FOR LIFE AT SEA

Like other marine mammals, pinnipeds have adapted for survival in the sea. They have large bodies, to take advantage of a low surface-area-to-body mass ratio, thus minimize heat loss due to conduction into the water. A thick layer of insulating fat called blubber acts as an energy reserve for the seal during times of fasting. Seals also hold their limbs close to the body to prevent heat loss. Their body temperature remains approximately 37.8 degrees Celsius with the skin about one degree warmer than the surrounding water. The heat-generating metabolic rate of seals is higher than land mammals of the same size. On land, blood vessels in the seal's skin dilate to release excess heat.

Seals' eyesight have evolved for swimming in dark water. Their eyes are large and contain a great number of low light photoreceptors (rod cells). They also have a well-developed tapetum lucidum, a layer of plates behind the retina that reflect light back through the retina a second time. Underwater, the pupils expand to let in the maximum amount of light available. In air, the eyesight of the seal is significantly reduced. Seals have lost the duct for draining eye fluids into the nasal passages like most land mammals in favour of a mucous that continually washes over the eyes to protect them, thus giving them a teary-eyed look out of water.

In all species, the external ears are small or absent. However, seals have evolved excellent hearing underwater, but diminished ability in air.

The seal's whiskers or vibrissae are its vibration detectors connected directly to the brain for homing in on prey. A seal can move each vibrissa individually by pushing the upper lip in and out.

The external genitalia and nipples are hidden in slits or depressions in the body, and the tail is very small. The forelimbs and hindlimbs are transformed into paddles with the humerus and femur limb elements within the body. Other aspects of the limbs, limb girdles, and spine are highly specialized for swimming. Most species have a relatively short rostrum. The teeth are usually all shaped like simple cones.

SEALS EXHALE TO DIVE

These animals can dive to extreme depths (over 1900 ft or 600 m for the Weddell seal) and remain underwater for up to an hour. Their heart rate is reduced while diving and more blood is supplied to the heart, lungs and brain by reducing the flow to the limbs. The amount of blood in a seal is greater than a land animal of the same size, so retains more oxygen. Also, seals have more of the protein myloglobin to store more oxygen and help prevent muscle oxygen deficiency. This gives seal meat its dark colour. Thus, unlike a land mammal, when a seal dives, it exhales to reduce air in the lungs because its oxygen is stored, instead, in the blood and muscle tissue.

Although seals have adapted to their marine environment and may stay at sea for several months at a time, they come ashore to breed, moult, give birth and nurse their young.

THE SEVEN SEALS OF NEWFOUNDLAND

The basis of the traditional sealing industry in Newfoundland was the harp seal (Phoca groenlandica), also known as the Greenland seal, saddle seal, and saddleback seal. This species is most abundant off the coast in late winter and early spring, estimated in 1990 at 3.1 million animals. Adult males may weigh 270 kg (400 lbs). Their irregular horseshoe-shaped dark band straddling the back give them their name. Harp seals accompany the Arctic ice southward and reach northern Newfoundland by mid-December, where one third go into the Gulf of St. Lawrence and the remainder continue down the east coast of Newfoundland. During January and February seals feed intensively on capelin, herring, polar cod, and crustacea such as shrimps to accumulate blubber.

Groups of seals called "patches" on the ice vary from 20 to 200 square kilometres (12-125 sq miles) and may contain as many as 2,000 adult harp females per square kilometre. Gestation is approximately 11.5 months including three months suspended development of the embryo to time all birthing to early March. A single yellowish pup is born on the ice, measuring about 80 cm (32 ins) long and weighing about 11 kg (24 lbs). In three days it becomes a fluffy white "whitecoat", grows rapidly into a "ragged jacket" on fat-rich milk for about 12 days, and by early April is a fasting "beater" swimming on its own, abandoned by the mother. After their April moult, adult harps and immature "bedlamers" (a corruption of the 15th century Breton phrase bêtes de la mer, "animals of the sea") migrate back to the Arctic before the ice has left the coasts of Newfoundland.

The hooded seal (Cystophora cristata) is much larger than the harp. The adult male may weigh 400 kg (900 lbs) and has an inflatable nasal cavity, which adds to its ferocious appearance in intimidatiog other males, and gives it its name. These seals also whelp on the Arctic ice, a little later than the harps. They will attack to defend themselves against humans. Like harp seals, they migrate back toward the Arctic when the ice breaks up. The population in 1990 was estimated at 500,000.

The grey seal (Halichoerus grypus) is an animal of considerable importance in the Gulf of St. Lawrence and in waters west of Newfoundland's Burin Peninsula. Grey seals are gregarious, sometimes forming large "patches" of several hundred on uninhabited offshore islands or secluded mainland beaches for springtime moulting. They are not, however, very sociable and keep a distance between one another. Occasionally males battle for females, and may sustain deep scars on their necks. Generally dark grey with few spots, grey seals have a wide variety of coat colours and patterns, and immature animals may have spotting that resembles the coat of a harbor seal. Pups are born with white coats and are unable to swim. In Newfoundland it is known as the host of the mature stage of the cod worm, which greatly detracts from the marketability of cod. It also eats a higher ratio of commercially valuable fish than do harp and hooded seals.

The smaller harbour seal (Phoca vitulina), only about five feet in length, is pale to dark grey with a pattern of rings or spots. Not migratory, but widely distributed within 20 km (13 miles) of the coasts as far north as Baffin Island and Greenland, this opportunistic feeder takes fish of commercial value as well as other species. Harbor seals congregate on islands, remote mainland coasts, or Arctic pack ice to breed, pup, and molt, but are also found relaxing in the warm sunshine on beaches, tidal mud flats, offshore rocks and reefs, buoys, wharves and even up fresh water river estuaries. They may live for up to 25 years, giving birth to one dark-coloured pup each spring. Mothers feed shrimp and other small prey items to their newly weaned pups.

The Inuit inhabitants along the Labrador coast and north make good use of the flesh, blubber, hides and viscera of two other species, the bearded seal or "square flipper" (Erignathus barbatus), and the ringed seal (Phoca hispida). The latter is smaller even than the harbour seal, and there is considerable variation in its colour. Its food is largely krill, crabs and prawns, but it also takes a variety of small fish such as smelts, herring and small cod.

Information adapted from Memorial University of Newfoundland, and the Federation for Animal Welfare.

Seal images, top to bottom: swilers at St. John's about 1900, Tyler the harp seal (Memorial U), bedlamer, harp seal, "whitecoat", hood seal in display, and Oscar the harbour seal (Memorial U).