Antarctic fishes |
Belgium's scientific exploration activities in Antarctica go back a long way, so it is no wonder that fish collected in this continent's waters should be on display at the Royal Belgian Institute of Natural Sciences. These animals were collected during various Belgian and French expeditions. Our Antarctic ichthyological faun collectiona comprises five orders, nine families, 35 genera and 54 species. Perciform fishes are the best represented order with the Zoarcidae (5 genera, 5 species), Nototheniidae (10 genera, 26 species), Bathydraconidae (7 genera, 7 species) and Channichthyidae (5 genera; 8 species) families. The Zoarcidae are found in both Arctic and Antarctic regions. The other three families belong to the Notothenioidei sub-order, which comprises most of the Antarctic coastal species. Although there is nothing spectacular about the shape or colour of these fishes, their physiology is quite remarkable.
Macrurus
lecontei Dollo,
1900 (-2800m).
Inventors of anti-freeze!
Several species are able to live at a temperature close to the freezing point of the sea water, owing to the glycoprotein in their blood (-1.9° C.). It is interesting to note that glomeruli (the main filtering structures of the kidney) are absent in these species.
Gerlachea
australis Dollo,
1900 (-450 m).
The Channichthyidae lack red blood cells so their blood is colourless. As water at low temperatures is 1.6 times more oxygenated than water at 20 °C, gas exchanges occur directly through the skin (cutaneous respiration).
Cryodraco
antarcticus Dollo,
1900 (-450 m).
Floating without a swim bladder
Antarctic cods, Nototheniidae, lack swim bladders and have developed another way of achieving buoyancy: their bodies are rich in fat and their skeletons poor in minerals.
Biblography
Gon, O. & Heemstra, P.C.(Editors), 1990, Fishes of the Southern Ocean., J.L.B. Smith Institute of Ichthyology, Grahamstown.
Miller, R.G., 1993, History and atlas of the fishes of the Antarctic Ocean., Foresta Institute for Ocean and Mountain Studies.