Fish
Emerald Rockcod
Trematomus bernacchii · also called emerald notothen
Rarely straying far from a small home patch of seafloor, an emerald rockcod is one of the most common fish species found anywhere along the Antarctic coastline, its narrow tolerance for cold water making it a closely watched indicator of change in the Southern Ocean.
Overview
The emerald rockcod, Trematomus bernacchii, is a Least Concern fish native to ocean and polar habitat across shallow coastal waters surrounding Antarctica. Its abundance as a model species for Antarctic fish research, its unusually small home range, and its extreme sensitivity to water temperature make it one of the more scientifically important fish species found anywhere in Antarctic waters.
A fish that stays close to home
While many fish species range widely in search of food, the emerald rockcod instead settles into a small patch of seafloor and rarely leaves, a stable, site-faithful lifestyle that has made it unusually convenient for researchers tracking the effects of a changing Southern Ocean.
Status
Least Concern, remaining abundant across most of its shallow coastal Antarctic range, though its narrow temperature tolerance makes it a species of ongoing scientific interest amid a warming Southern Ocean.
Emerald Rockcod: common questions
Why is the emerald rockcod important to Antarctic research?
This species is one of the most commonly encountered fish species along the Antarctic coastline, and its abundance and small home range make it a frequently studied model species for understanding Antarctic fish biology.
How far does the emerald rockcod travel during its life?
This species spends almost its entire life within a small home range on the seafloor, rarely moving far from a preferred stretch of shallow coastal habitat.
How does the emerald rockcod survive freezing water?
This species produces natural antifreeze glycoproteins that circulate in its blood, preventing ice crystals from forming even in the sub-zero temperatures typical of Southern Ocean coastal water.
Why is the emerald rockcod considered vulnerable to climate change?
This species is adapted to an extremely narrow range of cold water temperatures, making it especially sensitive to warming trends in its coastal Antarctic habitat compared with fish tolerating a wider temperature range.