New maximum depth record for bony fish: Teleostei, Scorpaeniformes, Liparidae (8336 m, Izu-Ogasawara Trench)

A new maximum depth record for bony fish (Teleostei) has been set at 8336 m deep in the Izu-Ogasawara Trench (NW Pacific Ocean) represented by video imagery of a snailfish probably Pseupodoliapris belyaevi or a new, endemic species since no physical specimen was captured. Sampling by trap and video was undertaken between 4534 and 9773 m and snailfish (Liparidae) were observed between 6824 and 8336 m, the deepest being a solitary juvenile. In the neighbouring Japan Trench, 31 deployments were made between 4913 and 8022 m and P. belyaevi was observed in 22 of the 24 deployments >6579 m. Two specimens, identified as P. belyaevi, were collected from 8022 m and represent the deepest fish ever caught. In the Japan and Izu-Ogasawara trenches at 6579-7001 m and 6824-7050 m, respectively, two other snailfish species were observed (Liparid sp. indet. 4-JPT and Liparid sp. indet. 4-IOT). A species of snailfish belonging to the putative 'ethereal' morphotype was also observed in the Japan Trench at 7621 and 8022 m (Liparid sp. indet. 3-JPT), but its identification beyond family is still obscure. This study also documents the first hadal fish from the Ryukyu Trench (Liparid sp. indet. 1-RKT) at 7079 and 7339 m.