Photo: Stephan Davies

On January 5th, Stephen Davies was out on his daily run at New Brighton Beach near Liverpool, UK when he came across what appeared to be the carcass of a sea monster that had washed ashore.  

He said: “I was running on the beach and thought ‘What’s that?’ because it looked quite big.

“I was talking to a fisherman who said it was a basking shark, which I don’t think are fairly common around here, but it could have been washed in by the tide.”

Others were not convinced that the carcass was from a shark, calling the remains the “New Brighton’s Nessie”.  It has often been suggested that the Loch Ness monster may be a wayward plesiosaur.  

Davies had every right to be surprised. The 15′ long decaying carcass looked remarkably like a  prehistoric plesiosaur. It just so happens that decomposing basking shark carcasses lose most of the lower head area and the dorsal and caudal fins first, making them resemble a plesiosaur.

There is a long history of decomposing basking shark carcasses being mistaken for sea monsters. In 1808, a large carcass washed ashore on the island of Stronsay in the Orkney Islands, Scotland. The Natural History Society of Edinburgh could not identify the carcass, dubbed the Stronsay Beast, and decided it was a new species, probably a sea serpent. On further examination, several biologists concluded that the carcass was of a decayed basking shark.

Over 150 years later, the Japanese fishing trawler Zuiyō Maru (瑞洋丸) caught the carcass of a large creature in its nets off the coast of New Zealand in 1977. The carcass’s peculiar appearance led to speculation that it might be the remains of a sea serpent or prehistoric plesiosaur. 

The crew was convinced it was an unidentified animal, but despite the potential biological significance of the curious discovery, the trawler captain decided to dump the carcass into the ocean again so not to risk spoiling the caught fish. However, before that, some photos and sketches were taken of the creature, nicknamed “Nessie” by the crew, measurements were taken and some samples of skeleton, skin and fins were collected for further analysis by experts in Japan. 

Several Japanese scientists were convinced that the remains were of a presumably extinct plesiosaur. Nevertheless, subsequent analysis of amino acids in the corpse’s muscle tissue later indicated it was most likely the carcass of a basking shark.

Thanks to Alaric Bond for contributing to this post.