JOANNA STOCKILL and STEWART EVANS consider evidence that whale sightings off the Northumberland coast are on the increase.
UNCONTROLLED hunting for whales during the 19th and 20th centuries is surely one of the worst environmental near-disasters of modern times. These magnificent creatures were once the undisputed rulers of the oceans.
Imagine, for example, the greatest of them all, the blue whale. It is probably the largest animal ever to exist on Earth, dwarfing modern land-lubbing giants such as the elephant, or even prehistoric ones such as the dinosaurs. The statistics of a new-born blue whale calf are frightening enough, since it is already about eight metres/26 feet long and weighs 3,050 kg/three tons! However, the average adult, weighing an astonishing 111,750 kg/110 tons and reaching some 25 metres/82 feet in length, almost beggars belief.
There were believed to be some 200-300,000 blue whales before whaling started. They were spread over all of the world's oceans, mating and calving in warm temperate or tropical waters in winter but feeding on rich supplies of plankton in polar regions in summer. They are remarkably fast swimmers for such large animals, being capable of speeds of up to 50 kph/30 mph. This was to their advantage during the early days of whaling because they were too fast to be captured by whalers using hand-held harpoons and operating from open boats.
Unfortunately, the invention of the exploding harpoon gun and its use from steam- or diesel-driven catcher boats in the latter part of the 19th century spelt disaster for them. They were now easy prey, and the carnage was unbelievable. It reached its peak in the early 1930s, with roughly 30,000 blue whales (equivalent to 10 per cent or more of the original population) being slaughtered in 1931 alone.
This level of exploitation was clearly unsustainable and the species became so scarce that whalers were forced to turn their attention to other species - especially the large ones, decimating their numbers too. Belatedly, the international body which had been formed in the late 1940s to regulate whaling, the International Whaling Commission, introduced a ban on hunting the blue whale in 1965. It was followed by a worldwide moratorium on all whale species from 1985/86.
Although the ban has now been in existence for almost 40 years for the blue whale and almost 20 years for all species, recovery has been a slow process. Scientific evidence has been slow to accumulate, not surprisingly in view of the expense of boat or plane surveys and the vastness of the oceans which need to be surveyed. Indeed, many scientists would argue that it is still too early to be certain that whales are on the increase at all. However, there are other - perhaps equally valid but far less expensive - sources of information than those provided by science.
Marine biologists from Newcastle University's Dove Marine Laboratory have been talking to fishermen and others, such as sailing enthusiasts and tour boat operators, who spend considerable amounts of their time at sea, about their sightings of whales. These scientists believe that we have a lot to learn from such people who may have decades of first-hand experience at sea and come from families whose livelihoods have depended on the marine environment for generations. Their surveys provide what may be early evidence of recovery.
The majority of people interviewed think that numbers of whales are at least holding their own, and roughly a quarter of them believe that sightings off the Northumberland coast are on the increase. One species at least - the minke whale - is now seen reasonably often, occasionally in large numbers. For example, Billy Shiels, who operates boat trips from Seahouses to the Farne Islands, recalled one trip chartered by a group of enthusiastic ornithologists who were intent on studying seabirds, on which he sighted minkes on 25 occasions.
Minke whales have even been seen by observers from the shore. One was reported off Souter lighthouse near South Shields last summer and volunteer wardens, who monitor various aspects of bird and sea life on and around the Farne Islands, recorded four sightings of minkes. The most unusual discovery was made by a Blyth fisherman. He captured part of the skeleton, including the intact skull, of a minke whale while trawling the seabed off the local coast.
While it is excellent news that minke whales are seen so often in the North Sea, increased sightings of this one species may not indicate a more general recovery of whale populations. Due to its smaller size, weighing in at about 10,160 kg/10 tons, the minke was less exploited than other species by whalers. There were still reasonable numbers of them in the seas when the ban on whaling came into force.
So what about the real giants of the oceans? Sightings of them in the North Sea are certainly less frequent than those of minkes, but here too the news is positive. Almost a third of fishermen and other sea-goers claim to have seen killer whales and longfinned pilot whales on their trips to sea. Still more exciting, there are claims that fin whales and sperm whales have been seen off our coast. Such sightings may raise questions of the reliability of the data: are they just misidentifications? For example, according to a recently published atlas of whales and dolphins in British waters, sperm whales do not occur in central parts of the North Sea.
However, credibility can be given to the fishermen's reports because three sperm whales were stranded off the east coast of England in 1997, and more recently, in 2004, two separate strandings have occurred in The Wash. So, although scientists have not yet recorded them in their surveys, they have certainly occurred here in the recent past.
The most tantalising of all claims was that a blue whale has been seen in our waters. Again, this species has not been 'officially' recorded here, although small numbers certainly occur off the Hebridean coast of Scotland. The significance of one North Sea observation is difficult to assess, even assuming that it was a correct identification. Perhaps this was a sighting of a stray blue whale, a one-off sighting unlikely to be repeated? Hopefully, it is more than this.
We feel that there is more than a realistic chance that further sightings will be reported in future years. Blue whales are unlikely ever to be common in the North Sea, but maybe they will recover to something like their former numbers in the world's oceans, and occasional visitors will grace our own part of the North Sea. Future generations of sea-going Northumbrians will not be too surprised if they do get a glimpse of one of them, nor will they be greeted with disbelief when they return to land with stories that 'the one that got away' was well over 20 metres/65 feet long! •
Picture: Kate Sutton