Deepest squid

The deepest squid observed in situ is a magnapinnid squid, or bigfin squid (genus Magnapinna) recorded close to the seafloor at a depth of 6,212 metres (20,381 feet) in the Philippine Trench in the western Pacific Ocean. This extends the bathymetric range of any squid species by 1,477 metres (4,846 feet) and is the first squid known to inhabit the hadal zone, the deepest region of the ocean starting at 6,000 metres (19,685 feet) below the surface. The observations were documented in a paper published in Marine Biology on 2 December 2021.

The previous depth record also belonged to a bigfin squid, spotted by a crewed submersible at 4,735 m (15,535 ft) in the western Atlantic Ocean.

First scientifically documented from a specimen caught off the Azores in 1907, bigfin squid (or long-arm squid) are characterized by their very large fins and very long, spaghetti-like arms and tentacles, both of which uniquely reach the same length.

This is not the first cephalopod sighted in the hadal zone. A dumbo octopus (genus Grimpoteuthis) was observed foraging at a depth of 6,957 m (22,825 ft) in the Java Trench in the Indian Ocean, as detailed in Marine Biology on 26 May 2020. This extended the previous bathymetric extreme among octopuses by 1,812 m (5,945 ft) and was the first irrefutable evidence of a cephalopod living in the hadal zone, although it had previously been conjectured this might be possible.

Both the bigfin squid and dumbo octopus papers were co-authored by Professor Alan Jamieson of the University of Western Australia's Deep Sea Research Centre (formerly of Newcastle University, UK) and Dr Michael Vecchione of the National Museum of Natural History in Washington, DC, USA.