Fishy Friday: Kroyer's deep-sea angler fish

Photo credit: Mary Levin

This is the first of a new series of posts called 'Fishy Friday.' On Fridays I'll search out, discover, explore, and explain species new to me, and hopefully, new to you...

Kroyers' deep-sea angler fish, Ceratias holboelli. Also called Northern seadevil.
Females are oblong, fleshy, with prickly skin, and fins set far back on the body. The eyes and pectoral fins are small, and the gill opening is oval in shape. Females also have a long, bioluminescent lure to attract prey, and two horny knobs on the back. The males are small and parasitic. They attach themselves to females where they remain throughout their lives. The two bodies form a two-bodied hermaphrodite - meaning, together they function as male and female simultaneously. Females grow to about 4 ft.

A rare, deep-dwelling fish, they occur worldwide in tropical to temperate seas from about 1,300 to 6,500 ft., but they may be found at the surface. They have been reported to feed on invertebrates.

Cool stats: Light only penetrates ocean water to about 1,000 feet. Below this photic zone, little to no plant life survives, making the deep sea a very unproductive mass of water. Many of the fishes living in the dark feed on organic prey that falls from above. The temperature can range from 50 to 37 degrees Farenheit. The pressure is intense, and there is very little oxygen. To adapt to the pressure, deepsea fishes have poorly-developed skeletal systems and lose, fleshy bodies. Many have complex bioluminescent lures and photophores to attract prey and mates. Most have large, gaping mouths.

Thoughts: I liken living in this environment to a game of hide-and-seek. If you can hide, you live. If you are found, you're eaten!