The Tasman Sea Monster

On April 25, 1977, a fishing vessel named the Zuiyo-maru of the Taiyo Fishery Company Ltd. was trawling for mackerel about 30 miles east of Christchurch, New Zealand, when a large animal carcass became entangled in its nets at a depth of 275 m (900 ft). As the massive creature, weighing about 4000 pounds, was drawn toward the ship and then hoisted above the deck, assistant production manager Michihiko Yano announced to the captain (Akira Tanaka), “It’s a rotten whale!” However, as Yano got a better look at the creature, he became less sure. 

Photo: Robert Tyndall via the Newcastle Herald

About 17 other crew members also saw the carcass, some of whom speculated that it might be a giant turtle with the shell peeled off. However, no one on board could say for sure what it was. Despite the possible scientific significance of the find, the captain and crew agreed that the foul-smelling corpse should be thrown overboard to avoid spoiling the fish catch. However, as the slimy carcass was being manoeuvered over the ship in preparation for disposal, it slipped from its ropes and fell suddenly onto the deck. This allowed the 39-year-old Yano, a graduate of Yamaguchi Oceanological high school, to examine the creature more closely. 

Although he was still unable to identify the animal, Yano felt it was definitely unusual, prompting him to take a set of measurements, along with five photographs using a camera borrowed from a shipmate. The total length of the carcass measured 10 meters (about 33 feet). Yano also removed 42 pieces of “horny fiber” from an anterior fin, in hopes of aiding future identification efforts. The creature was then released over the side and sank back into its watery grave. 

All of this took place within about an hour On July 20, 1977, as excitement and speculation about the find began to spread, officials from the fish company held a press conference to publicly announce their mysterious discovery. Although scientific analysis of the tissue samples and other data had not yet been completed, company representatives played up the sea-monster angle. The same day several Japanese newspapers published sensational front-page accounts of the find, soon followed by many other radio and television stories throughout Japan. Despite the creature’s size, scientists suggested the creature could be a dead sea lion, an adolescent whale, a decayed leatherback turtle or a blue shark. Creationists all encourage the plesiosaur.

After detailed analysis of the pictures and samples, several lines of evidence now strongly indicate that the Zuiyo-maru carcass was a large shark, and most likely a basking shark, rather than a plesiosaur.

In the case of monster carcasses washed ashore, they are often the decaying bodies of whales or sharks. The basking shark is one creature that is more likely to be mistaken for a sea monster after it is dead, rather than when it was alive. The basking shark, Cetorhinus maximus, is the second largest fish in the sea (surpassed only by the whale shark). It can grow to more than 30 feet in length, and specimens over 40 feet have been reported. Like the great blue whale, they are harmless filter feeders with enormous mouths.

The shark skims the surface of ocean eating tiny floating plankton. The water exits the shark’s mouth through large gill slits on the side of the head. Interestingly, basking sharks seem to have a propensity to mimic sea serpents while alive as well as dead. Often they feed in groups at or near the surface (hence their name), sometimes lining up two or more in a row. When they do this, the dorsal and tail fins protruding from the water can be, and sometimes have been, mistaken for multiple “humps” and head of a long-bodied sea-monster.

When the basking shark decays, the first areas to decompose are the cartilage areas around its face and gill area, causing the jaw to drop off and leaving the appearance of a long neck and small head. Its fins would become frayed and one of the two lobes of its tail would decompose first. The resulting mass could unwittingly be mistaken for a long necked sea creature with a long pointed tail.

In 1808 a body with a small head, mane, and a long neck reportedly was stranded on a beach in the Orkney Islands. Some of its vertebrae were kept at the Smithsonian Institute. When examined years later, they were almost identical to those of the basking shark.

As recounted by cryptozoologist Bernard Heuvelmans (1968), over a dozen supposed “sea serpent” carcasses of years past were later shown to be definite or probable shark carcasses, in most cases basking sharks.

These include the famous “Stronsa Beast” of Orkney Islands, England (1808), the Raritan Bay carcass of New Jersey (1822), the Henry Island, British Columbia carcass (1934) and the Querqueville monster, France, also in 1934.

These were followed by the Hendaye carcass in France (1951), the New South Wales carcass, (1959), and two more cases in 1961 (Vendee, France, and Northumberland, England). In 1970 another supposed “monster” washed up at Scituate, Massachusetts.

This 30-foot beast was said to look remarkably like a plesiosaur; however, it also turned out to be a decayed basking shark. In 1996 yet another supposed sea serpent was stranded on Block Island. Despite deep enthousiasm (the monster was nicknamed the “Block Ness Monster”), it was later evaluated as a probable basking shark.