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Antarctic acanthomorphs peculiarities

 image: G. Lecointre
caught in a net in Antarctica
The studies on antarctic acanthomorphs conducted by the team follow a scientific framework - the search of the relationships between species and the understanding of their biology - and the works of predecessors in the MNHN. In 1961, Jean-Claude Hureau, researcher at the MNHN at that time, led the first works  on these animals. He sampled, recognized and gathered observations on these species, in winter and summer as well, at station Dumont d’Urville (Terre Adélie). 30 years later, these initial works are still conducted now  by the teams of the MNHN in collaboration with those of the IPEV.

Antarctic acanthomorphs belong to only 21 of of the more than three hundred acanthomorph families. Two groups actually represent the majority of species found in the Southern Ocean: the liparids and the eight families belonging to the sub-order Notothenioidei.

Neopagetopsis ionah
Neopagetopsis ionah, Channichthyidae.
 Cygnodraco mawsoni
Cygnodraco mawsoni, Bathydraconidae.
Trematomus pennellii
Trematomus pennellii, Nototheniidae.
Paraliparis antarcticus
Paraliparis antarcticus, Liparidae.
 Bovichtus diacanthus
Bovichtus diacanthus, Bovichthyidae.
(Photographs: S. Iglesias and C. Ozouf.)

Liparids (snail fishes) mostly live in deep waters, and these species are less exposed to freezing temperatures. However, some species do possess antifreeze proteins. Five of the eight notothenioid families can live in the coldest antarctic waters: nototheniids, harpagiferids, channichthyids, bathydraconids and artedidraconids. These very cold waters often have a temperature below 0°C, but freeze only below – 1,86°C because of their salt content. However, teleost fishes have less salt than sea water, and are at the same temperature as their environment. Their internal liquids would freeze, but notothenioids produce an antifreeze protein that then circulates in their blood. They inherited it from a common ancestor.

For more specific information: see Lecointre and Ozouf-Costaz (2004 [1]).

References

  1. Lecointre G, Ozouf-Costaz C.  2004.  Les poissons antigel de l'océan Austral. Pour la Science. 320:48-54.