Using baited camera landers, the first images of living fishes were recorded in the hadal zone (6000-11000m) in the Pacific Ocean. The widespread abyssal macrourid Coryphaenoides yaquinae was observed at a new depth record of approximately 7000m in the Japan Trench. Two endemic species of liparid were observed at similar depths: Pseudoliparis amblystomopsis in the Japan Trench and Notoliparis kermadecensis in the Kermadec Trench. From these observations, we have documented swimming and feeding behaviour of these species and derived the first estimates of hadal fish abundance. The liparids intercepted bait within 100-200min but were observed to preferentially feed on scavenging amphipods. Notoliparis kermadecensis act as top predators in the hadal food web, exhibiting up to nine suction-feeding events per minute. Both species showed distinctive swimming gaits: P. amblystomopsis (mean length 22.5cm) displayed a mean tail-beat frequency of 0.47Hz and mean caudal:pectoral frequency ratio of 0.76, whereas N. kermadecensis (mean length 31.5cm) displayed respective values of 1.04 and 2.08Hz. Despite living at extreme depths, these endemic liparids exhibit similar activity levels compared with shallow-water liparids.
|Number of pages||9|
|Journal||Proceedings of the Royal Society B: Biological Sciences|
|Publication status||Published - 22 Mar 2009|