ON FEBRUARY 15 last year, a woman walking along a beach in the Scilly Isles spotted a large whale close to shore.
The animal turned out to be an extremely rare visitor to these waters. Bowhead whales seldom venture far from the polar ice-cap but this one was 2,000km south of its normal range.
A sighting off Cornwall last May was probably of the same animal. Then it was our turn to be visited. The crew of a pilot boat spotted a strange-looking whale at Carlingford on May 29.
The Irish Whale and Dolphin Group identified it as a bowhead, the 25th cetacean species to be recorded off Ireland.
The bowhead is a bizarre creature.
Severe obesity comes to mind; this is a huge rotund animal. As with baleen whales generally, females are larger than males.
They can be up to 18m long and weigh 75 tonnes. Living in very cold water requires a layer of insulating blubber up to 60cm thick.
The head, with its enormous mouth, is out of all proportion to the body, extending to a third of the whale’s length.
The tongue may weigh up to two tonnes and the plates of baleen, the sieve used to trap krill and fish, are the longest of any whale.
The bowhead swims relatively close to the sea surface, with its mouth open like that of a basking shark.
Only when it has trapped enough prey will it swallow the contents. Very slow swimmers, bowheads don’t travel south to warmer waters to give birth as other whales do.
This species has a special claim to fame; it may be the world’s longest lived mammal.
In 1986, the International Whaling Commission banned the killing of whales worldwide but native hunters in Alaska, Greenland, and Russia were granted exemptions.
A strict quota is enforced and the numbers taken reported to the commission.
In May 2007, a male bowhead was harpooned off the Alaskan coast.
As the hunters set to work with chainsaws cutting it up, a 13cm long spike was found lodged in the victim’s neck.
Such spikes, with explosive containers attached to them, were fitted to spears or fired from heavy shoulder guns.
Having penetrated the victim’s body, the explosive would detonate, causing horrendous injuries.
Perhaps the charge failed to go off in this instance; the whale was lucky to survive. Since the original find, several more harpoon tips have been found in bowhead carcasses.
The harpoon had been manufactured in New Bedford, Massachusetts.
Up to the 1880s, such spikes were made from walrus tusks or stone, but metal ones were used from then on.
Inuit hunters never targeted calves; the animal would have been a teenager when attacked. If so, it was at least 130 years old in 2007.
Another bowhead, found with the remains of a harpoon in its body, is thought to have lived for 211 years.
As a whale ages, changes occur in the amino acids of its eye lenses.
By measuring the composition of these, an animal’s age can be estimated.
Most of the whales tested had died in their 60s or 70s, but such startling age results were obtained occasionally that scientists doubted them.
The harpoon finds have confirmed the amino acid findings. Very large females, without calves, are seen from time to time. These oldies seem to have gone through the menopause.
A thousand years ago, Norsemen hunted bowhead and right whales, approaching them in small boats and spearing them with hand-held harpoons.
The carcasses of both species were so buoyant with oil that they floated, making them ideal quarry.
In the 17th century, Dutch whalers specifically targeted bowheads.
Over 100,000 bowheads were slaughtered before stocks became exhausted in the Atlantic.
Following the 1966 moratorium, numbers have recovered.
The bowhead is now in the IUCN ‘least concern’ category.
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