Yellowbelly Rockcod

• Its blood and tissues contain antifreeze glycoproteins that bind to microscopic ice crystals and stop them growing, a mechanism without which the fish would freeze from the inside.
• It has no swim bladder and makes up for the lack of buoyancy by storing lipids and reducing the mineralisation of its skeleton.
• It is one of the keystone species of the Antarctic coastal food web and regular prey for seals, shags and penguins.
• Its antifreeze glycoproteins evolved from a trypsinogen gene, a digestive enzyme: a much-cited case of how a gene changes function completely.
• Those proteins do not lower the freezing point the way car antifreeze would: they bind to ice microcrystals and stop them from growing.
• It is a red-blooded fish, which is why it is constantly used as the point of comparison against the icefishes: almost everything we know about their loss of haemoglobin has been measured against this species.
• The notothenioids make up around 90% of the fish fauna of the Antarctic continental shelf, a dominance with almost no equivalent in other seas.

Skeleton type

Vertebrate - internal bony skeleton (bony fish)

Habitat and environment

Rocky bottoms and kelp beds of Antarctica, from 0 to 550 m

Sources consulted: Chen, DeVries y Cheng (1997), PNAS · Cocca et al. (2000) · Lista Roja de la UICN · FishBase

The pins mark the parks and dive sites where its presence is documented.