Fatty acid composition and energy allocation in muscle and gonad tissues indicates that the female mackerel icefish Champsocephalus gunnari is an income breeder

The energy density and fatty acid composition profiles of the muscle and gonad tissues of female mackerel icefish Champsocephalus gunnari from Subarea 48.2 (the South Orkney Islands) were investigated throughout ovarian development to better understand the reproductive allocation strategy and the role of specific fatty acids in the reproductive process. Energy density in gonads increased from resting to spawning stages as the ovaries developed (19.60–25.10 kJ g⁻¹ DM). In contrast, energy density in muscles remained constant throughout ovarian development (20.13–22.87 kJ g⁻¹ DM), suggesting that the spawning events of the C. gunnari relies on energy income from feeding rather than on the energy stored in body. Additionally, the variation in fatty acid composition between muscle and gonad tissues may reflect the role of main FAs as energy source. These results suggest that C. gunnari may utilize an income breeding strategy. We highlight the importance of fish bycatch from krill fishery in elucidating ecology of Antarctic fish and therefore the dynamics of the Southern Ocean ecosystem. We further highlight the importance of sample and data from finfish fishery in understanding of fish ecology and the role of fish in the food web. We recommend the scientific contribution from fisheries in the Convention Area to the understanding of ecology of target and related fish species and the role of fish in the food web should be reviewed regularly to better conserve fish resources in the Convention Area.