Hot off the Press: A vast icefish breeding colony discovered in the Antarctic

During the RV Polarstern expedition to the southern Weddell Sea, in Feb 2021, a breeding colony of notothenioid icefish (Neopagetopsis ionah, Nybelin 1947) of globally unprecedented extent has been discovered. The colony, at time of survey, covered at least ~240 square kilometres of the eastern flank of the Filchner Trough and was comprised of fish nests at a density of 0.26 nests per square metre, representing an estimated minimum total of ~60 million active nests, and an associated fish biomass of > 60,000 tonnes. The majority of nests were each occupied by 1 adult fish guarding 1735 eggs (±433 SD). Bottom water temperatures adjacent to the nests were up to 2 °C warmer than the surrounding bottom waters, indicating a spatial correlation between the modified Warm Deep Water (mWDW) upflow onto the Weddell Shelf and active nesting.