The Northern Right Whale is on the edge of extinction, scientists say. A very small number were seen during the winter of 1998 off the coasts of Georgia and Florida in the US.

Only two mothers and their calves were spotted during the breeding season. Normally, several pairs of mothers with calves are seen, together with other single whales. Last year more than twenty visited the Georgia and Florida area.

"It's very scary," says Chris Slay of the New England Aquarium, a researcher who tracks whales. "Worldwide we believe that there are fewer than 400 Northern Right Whales."

These whales, which are found in the North Atlantic Ocean, are slow moving and dive in shallow waters. They became known as the ‘right’ whale to kill during whaling times. This was because they were easy to harpoon and floated for a long time after death. Their mouths contain huge plates of baleen that whalers called ‘whalebone’. They used it to make umbrella ribs, corsets, hoops in ladies dresses and whips. The rest of the whale was mostly turned into oil.

Adult Right Whales can grow to almost 18 metres long, and weigh up to 90 tonnes. They eat very small crabs and krill, filtering them with their baleen.

Despite their huge size, the whales' throats are so narrow that they are unable to swallow something the size of an orange. Their heads are covered in white growths called ‘callosities’. Researchers use these distinctive patches to recognise individual whales.

The biggest decline in whale numbers was during the 1800s. Whaling reduced the population from tens of thousands, to just a few hundred. Although protected by US law since 1935, the number of Right Whales has hardly changed since then.

Most Right Whales die from accidents with ships. The area of the sea where the whales give birth is now also one of the busiest shipping areas on the Florida coast. Nuclear submarines even use the area. Right Whales have no fin on their back, so they are very difficult to see. From a ship, only the flat of the whale's back is visible. But no whales have been killed in this way for two years, so this is not the only cause of their falling numbers.

Researchers say that the unusual weather caused by the 'El Niño' weather system is partly to blame for the lack of whale sightings. They think that it disturbs the deep ocean currents and so makes it more difficult for the whales to find food and each other. Scientists say that the next mating season will be the last chance for the Northern Right Whale.