Stories of sea serpents and other ocean-dwelling monsters are long-standing myths. Now, in research published in the journal Fish and Fisheries, one scientist has uncovered the culprit behind historical sea serpent sightings in the British Isles.

After parsing through over 200 reports of sea-serpent sightings made between 1809-2000, Robert France from Dalhousie University concluded that accounts of a “many-humped” monster lurking near the water's surface in the British Isles were actually early sightings of marine animals entangled in fishing gear. 

France scoured sightings published in historical newspapers, scientific journals, natural history books, cryptozoology texts, and even legally sworn testimonials. While sightings varied substantially, there were some common threads: The sea-serpent body stretched for tens of meters in length (up to 100m), formed many coils or humps at the surface, and frequently had hair or whiskers. Many reports suggested the serpents were capable of moving rapidly or reported them thrashing at the surface of the water. 

But France argues these descriptions conflict with all known  (living and extinct) marine animals and can be more easily explained when considering the possibility of a marine animal pulling lines of rope and buoys behind them. 

Today, the synthetic materials that impart strength and durability to fishing gear weave a tight cocoon around unfortunate animals tangled within their grasp. But before the advent of these materials, fishing gear was made of natural products that would have allowed for animals to move more freely while attached to fishing gear. Instead of succumbing to more instantaneous deaths we associate with entanglements today, animals may have simply carried their entrapment devices around with them until the natural materials eventually degraded. 

Beyond solving an age-old mystery that has enchanted sea-goers, France points to a more insidious narrative: marine entanglements have long been a pervasive problem, plaguing the oceans far longer than scientists expected.