Notothenioidei
| Notothenioidei | |
|---|---|
 |
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| An icefish off the coast of Antarctica. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Perciformes |
| Suborder: | Notothenioidei |
| Families | |
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Bovichtidae |
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Bovichtidae
Pseudaphritidae
Eleginopsidae
Nototheniidae
Harpagiferidae
Artedidraconidae
Bathydraconidae
Channichthyidae
See text for genera.
Notothenioidei is one of 18 suborders from the order Perciformes and includes Antarctic fish and sub-Antarctic fish. Notothenioids are distributed mainly throughout the Southern Ocean around the coasts of New Zealand, South America, and Antarctica. The main seawater temperatures between −2 and 4 °C (28 and 39 °F), but some the subpolar species inhabit waters that may be as warm as 10 °C (50 °F) around New Zealand and South America. Seawater temperatures below the freezing point of fresh water (0 °C or 32 °F) are possible due to the dissolved salts.
Notothenioids have a depth range of about 0–1,500 m (0–4,921 ft).
Comparison studies between sub-Antarctic and Antarctic notothenioids have revealed different ecological processes and genetic differences between the two groups of fish, like loss of hemoglobin and changes in buoyancy.
The notothenioids lack a swimbladder, and the majority of species are therefore benthic or demersal in nature. However, a depth-related diversification has given rise to some species attaining increased buoyancy, using lipid deposits in tissues and reduced ossification of bony structures. Reduced ossification of the skeleton in the notothenioids changes their weight and henceforth has created neutral buoyancy in the water, where the notothenioid neither sinks nor floats, and can thus adjust depth with ease.
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Wikipedia