Depth zonation and latitudinal distribution of deep-sea scavenging demersal fishes of the Mid-Atlantic Ridge, 42 to 53°N

Scavenging fishes of the Mid-Atlantic Ridge (MAR) were investigated using a baited autonomous lander equipped with a time-lapse camera between 924 and 3420 m water depth along 3 east–west transects at 42, 51 and 53°N across the MAR. We photographed 22 taxa at bait. Community structure analysis revealed 3 main assemblages, shallow (924 to 1198 m), intermediate (1569 to 2355 m) and deep (2869 to 3420 m), dominated by 3 species,Synaphobranchus kaupii,Antimora rostrataandCoryphaenoides(Nematonurus)armatus, respectively. Abyssal species in the axial valley region wereC. armatus,Histiobranchus bathybiusandSpectrunculussp. Compared with continental margin regionsA. rostratawere abundant and grew to a large size in the 2 northern transects, whereasS. kaupiiwere reduced in abundance and maximum depth of occurrence. The size, abundance and depth distribution ofC. armatuswas consistent with the hypothesis that these fish are part of a population mixing freely across the deep North Atlantic Basin. Temperature and latitude influenced distribution. (1) Five taxa were found only in the southern transect:Pseudotriakis microdon,Centroscymnus coelolepis,Simenchelys parasitica, Anguilliformes sp. andLepidion1 sp. (guentheri?). (2) Eight taxa were confined to the 2 northern transects:Bathyrajasp.,Coryphaenoides1 sp. (leptolepis?/mediterraneus?),Coryphaenoides2 sp. (leptolepis?/mediterraneus?),Macrourus berglax, young macrourids,Lepidion2 spp. (schmidti?),Anarhichas denticulatusand an unidentified zoarcid (Lycodonusn. sp.?/Lycenchelys alba?). (3) Eight species were ubiquitous across all 3 transects:Etmopterus princeps,Hydrolagus affinis,H. bathybius,S. kaupii,C. armatus,A. rostrata,Lepidion equesandSpectrunculus1 sp..