A new species of three-bearded rockling has been described from one specimen collected using a grab sample from the Tanoûdêrt Canyon off Mauritania at a depth of 595 m.
Gaidropsarus mauritanicus seeking shelter under the branched, whitish bryozoan Celleporina cf. lucida. Image credit: Tomas Lundälv, University of Gothenburg.
The order Gadiformes encompasses some of the most important species for today’s commercial fisheries.
There are also smaller species, such as the three-bearded rocklings of the genus Gaidropsarus, with nearly no commercial value but a remarkable distribution range.
“Over a quarter of the commercially caught marine fish worldwide belong to the cod family Gadidae, including Atlantic cod, Alaska pollock, and haddock, which are of particular economic importance,” said Dr. Alexander Knorrn, a researcher at Senckenberg am Meer and the University of Bremen.
“However, the order Gadiformes also includes much smaller, mostly unknown and poorly studied fish families, such as the rocklings (Gaidropsaridae), which are of little commercial value but have a remarkably wide range.”
The newly-described species inhabits the deep-water coral reefs off the coast of Mauritania.
“This is the location of the world’s largest deep-water coral reef complex, the Mauritanian Wall, which extends for at least 580 km, with a height between 80 and 100 m,” the biologists said.
Scientifically named Gaidropsarus mauritanicus, the new species is only about 7.3 cm long.
It is closely related to a Gaidropsarus species from Tasmania, a geographical point furthest among the samples studied by the team.
“Gaidropsarus mauritanicus could be distinguished from its congeners based on a combination of different characteristics, including the large eyes and the head, which takes up a quarter of the animal’s body length, elongated ventral fins, and the pink coloration,” Dr. Knorrn said.
“Genetic analyses confirm that this is a previously undescribed species.”
“Gaidropsarus mauritanicus was caught with the help of a grab, along with a variety of live deep-sea animals, including corals such as the framework-forming stony coral Desmophyllum pertusum or the red deep-water gorgonian Swiftia phaeton, as well as larger sponge colonies, bryozoans, brittle stars, annelids, decapod crustaceans, snails, and bivalves.”
“Also the video footage shows that Gaidropsarus mauritanicus exclusively lives in the deep-water coral ecosystems. One of the individuals we saw had whitish spots on its skin. It was the only fish we observed seeking shelter under a branched, whitish bryozoan, Celleporina cf. lucida.”
A paper describing the discovery was published in the Journal of Fish Biology.
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Alexander H. Knorrn et al. Gaidropsarus mauritanicus (Gadiformes, Gaidropsaridae) a new three-bearded rockling from a deep-water coral ecosystem with a genetically verified biogeographical distribution of the genus and notes to its ecology and behavior. Journal of Fish Biology, published online August 16, 2024; doi: 10.1111/jfb.15859
Source : Breaking Science News