The Atlantic stargazer (''Uranoscopus scaber'') is a marine, subtropical fish of family Uranoscopidae. Its body is suited for living on the sea floor, and is one of few fish capable of bioelectrogenesis, or the ability to generate an electric charge.

Distribution and habitat

It is widespread along the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe a ...

coast of Europe and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, is very common in the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

and

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Ro ...

, and somewhat rare in the

Bay of Biscay The Bay of Biscay (), known in Spain as the Gulf of Biscay ( es, Golfo de Vizcaya, eu, Bizkaiko Golkoa), and in France and some border regions as the Gulf of Gascony (french: Golfe de Gascogne, oc, Golf de Gasconha, br, Pleg-mor Gwaskogn), ...

. It is a

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 o ...

, which lives in sandy or muddy sand sediments along the upper slope of the continental shelf, between depths of 14–400 meters. It is not an economically important fish, primarily caught as by-catch, but is ecologically important.

Description

Typical of stargazers, its body is somewhat dorso-ventrally flattened, lacks a swimbladder, and has been found as large as 35.0 centimeters in length, but is usually between 20 and 30 cm. Its head and jaws are rotated upward, and has very large eyes and mouth. Its body is brown in color and can have numerous small light spots, with a lighter belly. It lives to about 5 or 6 years, and females are larger in size than males.

Biology

Feeding

Like other stargazers, it is an ambush predator which lies buried under sand with only its eyes showing. It has a large mouth, with a small strip of skin protruding from its lower jaw, which it moves in and out rapidly to act as a lure for prey. When a prey item comes near, the fish lunges toward the prey using a specially adapted vertebral column to generate the force by bending 60°, which takes less than 30

milliseconds A millisecond (from '' milli-'' and second; symbol: ms) is a unit of time in the International System of Units (SI) equal to one thousandth (0.001 or 10−3 or 1/1000) of a second and to 1000 microseconds. A unit of 10 milliseconds may be call ...

to engulf the prey. It feeds primarily on fish larvae and smaller fishes, such as

gobies Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising more than 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than in length, and the ...

, picarels, and small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s, but has also been known to eat

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...

echinoderms An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the se ...

annelids The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecolo ...

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular m ...

and plant material.

Reproduction

They can spawn between April and September, depending on the region, and produce pelagic eggs, about 2 millimeters in diameter. After hatching, the larvae, post-larvae, and juveniles remain pelagic. Males are slightly more common than females, but this can vary within local populations.

Electric organ

All species within the genus '' Uranoscopus'', along with those in '' Astroscopus'', have evolved electric organs, but lack receptor organs. These were both independently evolved, and are the only two genera within the order

Perciformes Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means ...

to produce electric organ discharges (EODs). The Atlantic stargazer, like other bioelectrogenic stargazers, produces pulse-type EODs while feeding and when it is disturbed. The Atlantic stargazer produces EODs with the electric organ, derived from sonic muscles. In other fishes, sonic muscles are used to produce sound by agitating the swim bladder.

References

{{Taxonbar, from=Q744000 Atlantic stargazer Fish of Western Asia Marine fauna of West Africa Marine fish of Europe Fish of the East Atlantic Fish of the Mediterranean Sea Fish of the Black Sea Fish of the North Sea Atlantic stargazer Taxa named by Carl Linnaeus