Five sperm whales have been found washed up on the east coast of England, and their deaths point to a worrying trend: beachings such as these are on the rise. The young males were discovered at Wainfleet, Skegness and Hunstanton; some scientists have suggested that confusion or hunger forced them to make a wrong turn from the Atlantic into the shallow waters of the North Sea.
While their reasons for being in such unsuitable waters is uncertain, post-mortem examination would suggest the whales died when the weight of their bodies crushed their internal organs. It is still unclear whether these stranded males are from the same pod as the 12 found beached earlier in January at the Wadden Islands archipelago, close to Germany.
Worldwide, scientists are only able to determine the cause of strandings in about 50 per cent of cases: “It is very hard to generalize about strandings – individual sperm whales could become stranded because of poor health conditions or navigational disorientation from following prey into unfamiliar shallow water”, explained Professor Scott Baker, of the Marine Mammal Institute at Oregon State University, speaking directly to The Student. He continued: “Mass strandings of healthy individuals are harder to explain.” By the time pathologists could gain access, the corpses in question had decomposed to an extent that masked much useful information.
However, scientists did find, “some squid beaks and little fragments of plastic”, in their intestines, according to Rob Deaville, project manager at the UK Cetacean Strandings Investigation Programme (CSIP). Although this would suggest the whales suffered dehydration and near starvation before they died, it is still difficult to ascertain the exact cause of death in this case. Physical damage, such as a ship strike, would leave obvious traces on the body of an animal. However, “some things would never leave a pathological legacy, such as if they were startled and disoriented by noise”, says Andrew Brownlow, of the Scottish Marine Animal Stranding Scheme.
Of course, this raises an important question as to whether human activity is to blame. In the past, the use of sonar in military exercises has been criticised for interfering with the whale’s natural direction system.
“If there was a massive naval exercise off the coast of Norfolk at the weekend I would be hugely suspicious” said Brownlow, speaking to a reporter from The Guardian. Scientists are still seeking information from the Ministry of Defence about whether this is the case.
Although there has been a sizeable increase in the number of Cetacean strandings and sightings since the inception of the CSIP in 1990, there is not enough evidence to eliminate theories that this is simply a natural phenomenon. It has been suggested that the combination of natural selection and the ban on whaling over the past three decades (precipitating a large population increase) may be the root cause.
Nonetheless, sperm whales occupy an important ecological niche in the oceans, and if these strandings are a reaction to human activities we must realise it soon – before the death toll reaches a critical level.
Image: Gabriel Barathieu