The spiny-back eel, ''Notacanthus sexspinis'', is a deep-sea spiny eel of the genus ''

Notacanthus Notacanthus is a genus of spiny eels in the family Notacanthidae. Species It currently contains these recognized species: * '' Notacanthus abbotti'' Fowler, 1934 (Mindanao spiny eel) * '' Notacanthus bonaparte'' A. Risso, 1840 (Shortfin spi ...

'', found in all the Southern Hemisphere oceans at depths between . The length of this fish is up to .

Description

The spiny-back eel is a slender, laterally compressed, elongated fish that can reach a length of . The snout projects above a small mouth on the underside of the head, and head and body are clothed in tiny

cycloid scales A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as we ...

. As with other members of the family Notacanthidae, there are no teeth on the maxillary bones and the premaxillary teeth form a comblike cutting edge. The dorsal fin takes the form of between six and fifteen isolated spines, with no soft rays. The anal fin is very long; it has ten to eighteen spines at the front and one hundred and fifty or more soft rays behind. The pelvic fin is in the middle of the abdomen and has one to three spines, and the caudal fin is minute. The general colour of this fish is brown, with darker brown around the mouth and on the soft-ray section of the anal fin.

Distribution

The spiny-back eel is a deep sea,

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occ ...

, living at depths between about in the Southern Hemisphere, in subtropical, temperate and subpolar waters. Its range includes the continental slope of South Africa, from Walvis Bay to Durban, the continental slope of South America from Brazil to Chile, and the continental slope to the south of Australia from Western Australia to Tasmania and New South Wales, as well as New Zealand. It is also found on knolls and

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

Ecology

As a

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

fish, the spiny-back eel feeds on the seabed, consuming

polychaete worms Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...

, small crustaceans and

coelenterates Coelenterata is a term encompassing the animal phyla Cnidaria (coral animals, true jellies, sea anemones, sea pens, and their relatives) and Ctenophora (comb jellies). The name comes , referring to the hollow body cavity common to these two phyl ...

. There are many more females than males, and mature males in breeding condition can be recognised by their darkened nostrils.

Description

Distribution

Ecology

References

Further reading