On Monday, an oarfish measuring nearly four metres from snout to tail was found tangled in a fishing net off the port of Imizu, in the north-coast prefecture of Toyama. The fish was already dead but was later taken to the nearby Uozu Aquarium to be studied.

Two more of the slender, snake-like fish were discovered in Toyama Bay nine days earlier. A record four oarfish were found in Toyama Bay in 2015 but that could be surpassed this year.

The species – characterised by long silver bodies and red fins – usually inhabit deep waters and the fish are rarely seen from the surface…