Larval stages of the Antarctic dragonfish Akarotaxis nudiceps (Waite, 1916), with comments on the larvae of the morphologically similar species Prionodraco evansii Regan 1914 (Notothenioidei: Bathydraconidae).

The notothenioid family Bathydraconidae is a poorly understood family of fishes endemic to the Southern Ocean. There is especially little information on Akarotaxis nudiceps, one of the deepest-dwelling and least fecund bathydraconid species. Using genetic and morphological data, we document and describe the larval stages of this unique species, offer a novel characteristic to distinguish it from the morphologically similar bathydraconid Prionodraco evansii and use the sampling locations to infer a possible spawning area of A. nudiceps along the western Antarctic Peninsula. These results provide important baseline information for locating, identifying and studying the biology of A. nudiceps, an important component of the Southern Ocean ecosystem.

Climate drives long-term change in Antarctic Silverfish along the western Antarctic Peninsula.

Over the last half of the 20th century, the western Antarctic Peninsula has been one of the most rapidly warming regions on Earth, leading to substantial reductions in regional sea ice coverage. These changes are modulated by atmospheric forcing, including the Amundsen Sea Low (ASL) pressure system. We utilized a novel 25-year (1993-2017) time series to model the effects of environmental variability on larvae of a keystone species, the Antarctic Silverfish (Pleuragramma antarctica). Antarctic Silverfish use sea ice as spawning habitat and are important prey for penguins and other predators. We show that warmer sea surface temperature and decreased sea ice are associated with reduced larval abundance. Variability in the ASL modulates both sea surface temperature and sea ice; a strong ASL is associated with reduced larvae. These findings support a narrow sea ice and temperature tolerance for adult and larval fish. Further regional warming predicted to occur during the 21st century could displace populations of Antarctic Silverfish, altering this pelagic ecosystem.