Icefish
Icefish
‘Icefish’ covers many species including members of the Channichthyidae, or Chaenichthyidae family. Also known as Crocodile Icefish and White Blooded Fish their blood has less oxygen - they lack red blood cells and haemoglobin.
Conservation status
They are vulnerable to rising sea temperatures which melt the ice covering their nests - exposing young fish to predators. Shifting algal patterns also affect their food sources. Moreover, Icefish create localised and concentrated communities so local environmental changes could destroy an entire colony.
Pike Icefish Champsocephalus esox is listed as Vulnerable by The IUCN Red List. The species has declined by up to 80% since the 1980s along the Chilean coast of the southern Patagonian Sea. Less is known about the population living in the Argentinian region. The species are limited to seas with low temperatures and high oxygen content and are vulnerable to climbing sea temperatures as well as to bycatch and invasive salmon.
Overview
The majority of the 16 species of crocodile Icefish can be found in the Antarctic and live on crustaceans and small fish. They create vast communities – millions of nests distributed close by to one another on the ocean floor (each guarded by a single Icefish). In 2021, scientists found a colony of Neopagetopsis ionah icefish with around 60 million active nests (each containing around 1,735 eggs) on the seabed of the Weddell Sea (Antarctica).
Icefish have large hearts and gill blood vessels which allow a large volume of blood to circulate around their bodies - from which the fish can extract the oxygen they need. Icefish have evolved to survive in cold and icy waters (their ancestors adapted to the freezing of the Antarctic Seas – 30 million years ago). They have large heads and mouths, a slow metabolism, transparent bodies, and can live up to 40 years. Icefish play a key part in Atlantic ecosystems and their ability to adapt to extreme conditions, high pressures, and icy temperatures could provide insights for scientists searching for medicines for human disease.
Sources
https://www.britannica.com/animal/icefish
https://www.popsci.com/animals/icefish-nests-found-in-antarctica/
https://en.wikipedia.org/wiki/Channichthyidae
https://www.iucnredlist.org/species/159100452/159404825