Antarctic butterfish

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Antarctic butterfish
Drawing by Dr Tony Ayling
Drawing by Dr Tony Ayling
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Centrolophidae
Genus: Hyperoglyphe
Species: H. antarctica
Binomial name
Hyperoglyphe antarctica
(Carmichael, 1819)

The Antarctic butterfish, deepsea trevally, blue eye trevalla, bluenose sea bass, or deep sea trevalla, Hyperoglyphe antarctica, is a medusafish of the family Centrolophidae found in all the southern oceans, at depths of between 40 and 1,500 m. Its length is up to about 140 cm, with a maximum published weight of 60 kg. These fish are normally found in deep waters out of reach to the majority of recreational anglers. However there is increasing effort targeting these fish recreationally using droplines or deep-water handlines.

The Antarctic butterfish is similar to the hapuku - it is completely unrelated but the confusion has given rise to another common name, blue-nose grouper, in New Zealand.

[edit] General characteristics

The Antarctic butterfish has an abruptly blunt snout, long dorsal and anal fins, and a forked caudal fin. They are blue-black on the back, sometimes with a brownish tinge, and silver-blue flanks and belly. There are a number of small cream coloured dots around the mouth and lower jaw and the eyes are golden with an inner black ring. The mouth is large with a single row of small teeth in each jaw and it is a voracious carnivore, feeding on squid, crabs, lantern fish, and small ling.

Antarctic butterfish have a dark blue body above and lighter blue below with large eyes (another name for this fish is big eye). Larger individuals have a bronze sheen along the flanks.

They can grow to 1.4 m in length and over 50 kg in weight. Studies have shown that fish between 62 and 72 cm are mature and range in age between 8–12 years respectively. Mature females can produce between 2 million and 11 million eggs prior to spawning.

Blue eye mainly feed on the tunicate Pyrosoma atlantica. However they will feed on a range of fish, molluscs, squid and crustaceans, they are also cannibalistic.

[edit] Reproduction and distribution

Spawning appears to occur in an area north east of Tasmania during March and April.

Little is known about the egg and larval stages of blue eye. Recently Antarctic buttefish of approximately 10 cm have been found living in association with large masses of floating kelp. It is believed that as these juveniles reach 50 cm they become semi-bottom dwelling.

These young fish form schools over hard bottom at depths of around 350–450 m, moving to deeper waters as they grow.

[edit] References

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