Dozens of sea turtles have been found dead off a beach of a remote Japanese island, with many having been stabbed in the neck. Japanese media has reported that the grisly scene may have been caused by fishermen who attempted to free the trapped animals from their nets but decided to put them out of their misery. 

People on Kumejima island in Okinawa discovered the bodies of around 30 green sea turtles last week after a low tide revealed their bodies, Osaka-based newspaper the Asahi Shimbun reports. Several of the turtles had stab wounds on their necks and a number of others had bloody slash marks on their flippers.

Police are investigating the incident as a possible case of animal cruelty and are reportedly in the process of questioning witnesses. While authorities are yet to comment on the deaths, one anonymous source "close to the matter" said that a local fishing company might be to blame. 

“A lot of them were tangled up in fishing nets. I disentangled some of them and released them into the sea, but I couldn't free heavy ones, so I stabbed them to get rid of them," said the fishery operator, according to a source speaking to The Mainichi.

The green sea turtle (Chelonia mydas) can be found in waters across the world, with their natural range extending throughout the tropical and subtropical seas of the planet. However, the species and their home are facing mounting problems.

The species is considered to be endangered with extinction, according to the IUCN Red List. 

Their current population numbers are decreasing and they face a myriad of threats, most of which are the result of human activity. The degradation of their natural habitat is a major issue, but one of the most detrimental factors is the intentional harvests of eggs and adults from nesting beaches. 

As this latest incident shows, they also come into conflict with fishermen who frequently catch them in fishing nets as accidental by-catch. 

Their diet mainly consists of algae and seagrasses, but they also forage on sponges, small invertebrates, and discarded fish. Sadly, their food supply is becoming increasingly contaminated with plastics. In 2018, scientists looked at seven species of sea turtles living in three different oceans and found that all individuals – every single one – had microplastics in their guts.