Stomach content analysis of mesopelagic fish from the southern Kerguelen Axis

Mesopelagic fish gut content data from the Kerguelen Axis ecosystem study (AAS_4344): These data are based on samples collected as part of the Kerguelen Axis marine ecosystem study (AAS_4344), chief scientist Andrew Constable. This research was supported by the Australian government under the (i) Cooperative Research Centre Program through the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC), (ii) Australian Antarctic Science Program (Projects 4343, 4344, 4347 and 4366), and (iii) Australian Research Council’s Special Research Initiative for Antarctic Gateway Partnership (Project ID SR140300001). The preferred citation is: Riaz, J., Walters, A., Trebilco, R., Bestley, S., Lea, M-A. (2019) Stomach content analysis of mesopelagic fish from the southern Kerguelen Axis. Deep Sea Research Part II: Topical Studies in Oceanography. Samples for gut content analysis were collected on board the R.S.V Aurora Australis during the austral summer of 2016 (22 January-17 February) during the Kerguelen Axis marine ecosystem survey (AAS_4344). Analyses focused on four of the most common and widespread Southern Ocean mesopelagic fish species: three myctophids (Electrona antarctica, Gymnoscopelus braueri, Krefftichthys anderssoni), and one bathylagid (Bathylagus antarcticus). Species were sampled across a broad range of size classes to investigate the influence of predator size on predator and prey size relationships. Fish were collected from six sampling stations along the major south-to-north transect of the Kerguelen Axis. Three sampling sites were located in subpolar waters south of the Southern Boundary (SB) of the Antarctic Circumpolar Current (ACC) over the Princess Elizabeth Trough. The other three sampling sites were located north of the Southern Antarctic Circumpolar Circulation Front (SACCF) over the Banzare Bank on the southern Kerguelen Plateau.The contribution and relative importance of prey taxa to stomach contents was quantified with four traditional metrics of dietary composition (Hyslop 1980). These were calculated for each fish species separately at northern and southern sampling stations, and across species within all stations. Hyslop, E. J. (1980) Stomach contents analysis-a review of methods and their application. Journal of Fish Biology 17:411.