Mythical sea monsters aren’t all that different from some of the real-life creatures of the deep – but being lily-livered humans (with compressible lungs), few of us get to see them in real life. Every now and then we do get an opportunity to spot an ocean giant in the flesh as their bodies wash ashore. Dead animals are gassy beasts, meaning even enormous animals can achieve buoyancy and float around on ocean currents. When these currents deliver them to our doorstep, it triggers a flurry of investigation as teams work against the clock – very necessary with decaying animals – to find out how and why the animal died, and what on Earth it is.
This is often easier said than done when dealing with decomposing carcasses that have been at sea for a while, acting as a floating buffet for hungry fish and seabirds alike. You can understand, then, why the Marine Environmental Monitoring (MEM) team – an Environmental Conservation Organization scheme partnered with the UK Cetacean Strandings Investigation Programme – first thought they might have a whale on their hands when an eight-meter (23-foot) blob emerged on the coast of Wales.
Having decomposed a fair bit, “blob” really was the best word for what remained of the unidentified sea creature. The MEM team got to work photographing whatever features they could find so that, in partnership with the London Natural History Museum, they could positively ID the mess of cartilage and tissue. Investigations confirmed the deceased beast was in fact a basking shark (Cetorhinus maximus), an enormous species of filter-feeding shark.
“Anything that gets stranded and dies on a beach we get notified and then what we’ll try and do is investigate what the cause of death is,” said Strandings Coordinator for Wales Mat Westfield in a call with IFLScience. “Unfortunately, we can only normally do that in really fresh animals… With this one it was not possible so we went along to confirm what the creature actually was.”
When fresher dead animals are found, Westfield and his team organize the transport of specimens to London Zoo, where a necropsy can be conducted to work out what killed them. While it’s of course too late for the animal being dissected, the outcome can arm conservation organizations with the information they need to bring about better protection for marine species. As an endangered species, gathering information on basking sharks is crucial work, but they are a very rare find for strandings teams in the UK even though they are often sighted alive at sea.
“We get reports from fishing boats that have seen them out in the water,” said Westfield. “They get their name basking shark because they basically sit just below the surface and feed on zooplankton… They only travel at about one to two miles per hour so they just slowly cruise along which makes them look like they’re basking in the sunlight.
“It’s very rare for them to actually get washed up onto the coastline like this. We did get a report of one last year in Newport but we weren’t quick enough to arrive so the tide took it away before we could get it. It was in the same condition as this one having been out at sea for quite a while before washing up on the shoreline.”
This latest specimen, which is estimated to weigh around four to five tons, poses a logistical challenge as it chose one of the more remote beaches in Wales to land on. Without vehicle access, removing the animal is near-impossible. Since we’ve hopefully all learned by now that blowing up whale carcasses is a recipe for disaster, Westfield says they’ll most likely bury it on site.