Antarctic fishes

Antarctic fishes are species living in the Southern Ocean and surrounding cold waters. Many belong to the notothenioid radiation, which includes species with antifreeze proteins and, in some lineages, no hemoglobin.

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Southern Ocean: The ocean surrounding Antarctica, shaped by the Antarctic Circumpolar Current and distinct water masses. Its cold, connected waters define the main marine habitat of Antarctic fishes.
Antifreeze glycoprotein: A protein that binds ice crystals and inhibits their growth in body fluids. Several Antarctic notothenioids use these molecules to prevent ice growth in blood and tissues.
Antarctic toothfish: A large predatory notothenioid fish found in deep Southern Ocean waters. It is a major predator and a commercially harvested species in parts of the Southern Ocean.
Notothenioid adaptive radiation: The diversification of notothenioid fishes into ecological roles across Antarctic and sub-Antarctic waters. It accounts for the lineage’s extraordinary share of fish diversity around Antarctica.
Southern Ocean food web: The network of feeding relationships among organisms in the Southern Ocean. Antarctic fishes transfer energy from invertebrates and plankton to larger predators.
Notothenioidei: A suborder of percomorph fishes that includes most of Antarctica’s diverse bottom-associated fish species. This lineage accounts for much of the region’s fish diversity and many hallmark adaptations.
Ice-binding protein: A protein that binds ice surfaces and alters ice growth or recrystallization. This broader protein class includes the antifreeze molecules found in Antarctic fishes.
Patagonian toothfish: A large deep-water notothenioid fish distributed around sub-Antarctic and temperate southern waters. Its fishery and overlap with Antarctic toothfish make it central to Southern Ocean management.
Antarctic glaciation: The development and expansion of ice sheets on Antarctica over geological time. Cooling and habitat change helped shape the evolutionary setting of Antarctic fish diversification.
Antarctic marine ecosystem: The interacting organisms and physical environments of the seas around Antarctica. Fish populations form part of an ecosystem strongly shaped by sea ice and seasonal productivity.