Illustrated here are the larval and
adult forms of deep sea angler fish. Deep sea anglers, suborder
Ceratioidea, are represented by about 120 species, belonging
to eleven different families. Note that the larval form (? Melanocetus
sp.) is surrounded by a gelatinous epidermal layer, possibly providing
protection, and has not yet developed the lure. In comparison
the adult (Melaoncetus sp.) obviously displays its fishing
pole lure. Both images were taken by Dr Peter Herring while on
board the RS Discovery Vessel.
Deep sea anglers differ from other
anglers by the absence of ventral fins. Whereas other anglers
live on the bottom from shallow to deep water or, in a few cases
such as the Sargassum
Angler Fish (Histrio histrio), at the surface, the
deep sea ceratioid anglers are mostly midwater forms, ranging
in depth from from perhaps one thousand to several thousand feet.
Only the females have fishing poles. Since in the depths it would
be difficult to see the lure, the tip is usually equipped with
a light-producing organ of some kind. It is not known for certain
how this light is produced; one suggestion is that luminescent
bacteria are responsible.