A couple of monkfish surprised in the abyss: a first

Nathalie Mayer Journalist

It is off Portugal, 800 meters deep, that images of a couple of monkfish were filmed. Unpublished images of a certain scientific value.

LULA1000 : the small name of a submersible specially designed to film in the ocean depths in high definition. And he has just brought back to scientists, priceless images of a couple of abyssal monkfish - known scientists under the name Caulophryne jordani - living some 800 meters deep. "Never seen," says Ted Pietsch, world expert at the University of Washington (USA).

Because although there are about 160 species of monkfish, it is rare. It is known by only 14 individuals preserved in natural history museums. Still, it's all about females. Never had any male been observed before. And even less alive! On the one hand because these animals do not support being extracted from their natural environment . On the other hand because the males, tiny, live little free time. They spend their lives fixed on the body of their female, like parasites. The observation of a couple is a bargain, to appreciate to its true extent.

This abyssal monkfish has fin radii independent of each other and emitting light by bioluminescence. © Rebikoff-Niggeler Foundation

Inestimable observations in the wild
"To understand the biology and ecology of a species , nothing replaces observations in the wild," says Ted Pietsch. And indeed, these unpublished images revealed body structures and behaviors also never seen before.

Thus, usually, the fin rays of fish are joined by membranes. Here, they move independently. " To form a kind of network of sensory antennas similar to cat whiskers , " Ted Pietsch assumes. As for the luminous points scattered along these rays, they could help the monkfish to attract prey or, on the contrary, to calm the ardor of the predators by making the fish pass for more formidable than it is.

To know more

A strange monkfish found in the abyss

Discovered more than a thousand meters deep in the Gulf of Mexico, this small fish looking like angler is a new species. However, we see him as a cousin of monkfish and his family is well known in the abyss.

Article by Jean-Luc Goudet published on 09/08/2015

"Every time we go for deep-sea research , there's a good chance we're bringing something new , " says Tracey Sutton in a statement from Nova Southeastern University ( NSU ). This young PhD researcher is working at the Halmos College of Natural Science and Oceanography and presents the find of the latest expedition to the Gulf of Mexico: a representative of a new species of fish (new to the eyes of humans ...). Three individuals were observed between 1,000 and 1,500 m depth, ranging in size from 3 to 9.5 cm.

It looks strange, with a rather deformed body and a kind of fishing rod above the head. These characteristics are known: they are those of monkfish (or monkfish, once decapitated and reached on the fishmonger's stall), also called fish-fishers. This appendage (actually the first spine of the dorsal fin) actually serves to fish and, in passing. The fish moves it in all directions (the joint is remarkable), which moves the flap of skin that ends it, passing the bait for an appetizing little animal in the eyes of other fish. If the size of this potential victim suits him, monkfish suddenly opens his huge mouth, swallowing the water and its contents.

A female Lasiognathus , less than 10 cm long, with its long fishing rod and a huge mouth as a net. © Theodore Pietsch, Ph.D., University of Washington

This monkfish can only be a female

The newcomer is therefore a lophiiform. It is also a ceratiid (or ceratoid), a superfamily of fish living at great depth. In the dark waters of the abyss where animals are rare, this fishing rod, complete with luminous lures, is a very advantageous instrument for finding prey. The authors, who publish their discovery in the journal Copeia , classify the fish in a known genus, Lasiognathus .

We can even say that it is a female because, in lophiiformes, the males are tiny and cling by the mouth to a female when they find one. In terms of bite , the skin of both partners is gradually digested, as the organs of the male who eventually reduces to his testicles , which, when the time comes, respond to female hormones by ejecting sperm .

This is not the first time an observation of this kind has been publicized. On November 17, 2014, Bruce Robison, from the MBARI Ocean Research Center, was filming a "sea dragon" (English nickname for ceratiids) in Monterey Bay on the California coast of the United States.

Source: https://www.futura-sciences.com/planete/actualites/zoologie-couple-baudroies-surpris-abysses-premiere-59290/