Habitat Severity and Internal Ice in Antarctic Notothenioid Fishes

Notothenioid fishes live in the world's coldest marine waters surrounding Antarctica and have evolved strategies to avoid freezing. Past studies have shown that most Antarctic notothenioids produce special antifreeze proteins that prevent the growth of ice crystals that enter the body. While these proteins help prevent individuals from being killed by growing ice crystals, it is unclear how these fish avoid the accumulation of these small ice crystals inside their tissues over time. This project will observe how ice crystal accumulation relates to the harshness of a fish's environment within different habitats of McMurdo Sound, Antarctica. The researchers collected fishes and ocean observations at different field sites that cover a range of habitat severity in terms of temperature and iciness. The researchers installed an underwater ocean observatory near McMurdo Station (The McMurdo Oceanographic Observatory, MOO; Nov. 2017 - Nov. 2019) which included a conductivity-temperature-depth sensor (CTD), a high-definition video/still image camera and a research quality hydrophone. The observatory produced oceanographic data, time-lapse images of the immediate environs, and a high-resolution hydroacoustic dataset from the entire deployment. Seawater temperature data loggers were also deployed at other shallow, nearshore sites around McMurdo Sound to provide context and assessment of environmental conditions experienced by the fishes.