Uranoscopus scaber (Stargazer) | INFORMATION

Scientific Classification

Rank	Scientific Name
Kingdom	Animalia animals
Phylum	Chordata chordates
Subphylum	Vertebrata vertebrates
Class	Actinopterygii ray-finned fishes
Order	Perciformes
Family	Uranoscopidae Stargazers
Genus	Uranoscopus
Species	Uranoscopus scaber Stargazer

By Alex Letulle

Geographic Range

The Atlantic Stargazer is widely distributed along marine waters of the Atlantic coast of Europe to Portugal, the Gulf of Guinea, the Black Sea, the Red Sea, the Mediterranean Sea, along the northern coast of Africa, and infrequently distributed amongst the Bay of Biscay.

Habitat

Atlantic stargazer, a benthic species, are usually found in warm, subtropical waters at depths of 15 to 400 m. The demersal adults spend most time burrowed into the sand and mud substrates of the continental shelf and upper slopes, while the life stages from egg to juvenile are pelagic.

Habitat Regions
tropical
saltwater or marine

Aquatic Biomes
benthic
reef
coastal

Physical Description

Atlantic Stargazers and other members of Uranoscopus are easily recognized by a large, dorsally-flattened and square head with dorsolaterally placed eye. A protractible and tooth-filled mouth opens vertically with the lower jaw extending past the upper jaw. The lower mandible possesses unique processes such as tiny sensory appendages called cutaneous cirri that line the bottom lip and a long, slender outgrowth of the oral valve at least as long as eye diameter. A poisonous cleithral spine four times the head length located dorsoposterior to the gill cover. Long, somewhat compressed body extending posteriorly from the broader head with two dorsal fins and an anal fin; the first dorsal fin has 3 to 4 spines, the second dorsal fin has 13 to 15 soft ray, and the anal fin has 1 spine and 12 to 14 soft rays. The Atlantic stargazer has a white mottled greyish-brown dorsal and lateral scales with a yellowish underside. Average size of the Atlantic stargazer is 25 cm; females typically attain a larger size than males with an average maximum length of 30 cm and 26 cm.

Other Physical Features
bilateral symmetry
poisonous

Sexual Dimorphism
female larger

Development

No information found for this species

Reproduction

No information found for this species

Atlantic stargazers migrate to more open waters during a spawning period from March to September with a peak in May. As the length and weight of the female Atlantic Stargazer increases, so does the amount of viable eggs produced during the spawning period. The pelagic eggs range from 0.62 mm up to a maximum of 1.86 mm after fertilization. The individuals inhabit pelagic waters throughout larval, post larval and juvenile stages.

No information found for this species

Lifespan/Longevity

Recent studies of Atlantic Stargazer in the Eastern Mediterranean Sea determine lifespans do not exceeding 5 years while earlier studies in the Western Mediterranean Sea reported fish reaching 6 years.

Behavior

Being nocturnal predators, the Atlantic Stargazer spends much of the day motionlessly buried in the sand or mud and are more active at night. The stargazer leaves only the eyes and mouth above the sand and lie in wait for small fish, yet are known to react to inanimate objects such as rocks and trash. For reasons that still remain unknown, studies consistently report Atlantic Stargazer and a species of Mediterranean Sea croaker, Sciaena umbra, to congregate in clusters.

Key Behaviors
natatorial
motile

Communication and Perception

No information found for this species

Perception Channels
tactile
chemical

Food Habits

The Atlantic Stargazer buries itself with only the eyes and mouth above the substrate. As ambush predators, they lie in wait for prey to come within a certain distance before attacking. The protractible appendage of the mouth is used as a lure to attract small fish by waving it around. The major prey of the Atlantic stargazer are small teleosts with a contributing diet of crustaceans, molluscs, echinoderms, and annelids. The Atlantic Stargazer shows an increased feeding activity during the Fall which decreases until it reaches a low in the Summer.

Primary Diet
carnivore
- piscivore

Animal Foods
fish
aquatic crustaceans

Predation

While the only recorded natural predators of the Atlantic stargazer are Bottlenose Dolphins, they are often caught as bycatch in gillnets.

Anti-predator Adaptations
cryptic

Ecosystem Roles

The Atlantic Stargazer is a host to many parasites such as common intestinal/stomach parasite Hysterothylacium aduncum, and nematode species Philometra globiceps. A reduction in populations of the Atlantic Stargazer in the Northwestern Mediterranean Seas was due to the invasive alga species Caulerpa taxifolia that reduce the sandy groundcover.

Economic Importance for Humans: Positive

The Atlantic Stargazer is not commercially important in the Eastern Mediterranean Sea, while it makes up 2.6% of total caught fish by trawls in the Western Mediterranean.

Positive Impacts
food

Economic Importance for Humans: Negative

No information found for this species

Conservation Status

Studies show that Atlantic stargazer has a low exploitation rate, even in comparison to other bottom dwelling fish in the area, therefore, it is assessed as a species of “Least Concern” by the International Union for Conservation of Nature Red List with no plans to manage the species in place.

Additional Links

Encyclopedia of Life

Contributors

Alex Letulle (author), Louisiana State University, Prosanta Chakrabarty (editor), Louisiana State University.

tropical: the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

saltwater or marine: mainly lives in oceans, seas, or other bodies of salt water.

benthic: Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

reef: structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

coastal: the nearshore aquatic habitats near a coast, or shoreline.

bilateral symmetry: having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

poisonous: an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

cryptic: having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

food: A substance that provides both nutrients and energy to a living thing.

carnivore: an animal that mainly eats meat

piscivore: an animal that mainly eats fish

natatorial: specialized for swimming

motile: having the capacity to move from one place to another.

tactile: uses touch to communicate

chemical: uses smells or other chemicals to communicate

References

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Carpenter, K., L. de Morais, W. Smith-Vaniz, G. de Bruyne. 2015. "Uranoscopus scaber, Atlantic Stargazer" (On-line). The IUCN Red List of Threatened Species 2015. Accessed October 01, 2017 at http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T198722A42691994.en .

Coker, T., S. Leblebici, S. Ozaydin, O. Akyol, Z. Tonsunoglu. 2008. Determination of batch fecundity in Uranoscopus scaber Linnaeus, 1758 from the Aegean Sea, Turkey. Journal of Applied Ichthyology , 24: 85-87. Accessed October 01, 2017 at http://rdcu.be/Adtx/ .

Deudero, S., G. Morey, N. Polunin, J. Pinnegar, B. Morales-Nin. 2004. Spatial variation and ontogenic shifts in the isotopic composition of Mediterranean littoral fishes. Marine Biology , 145: 971-981. Accessed October 01, 2017 at Springer-Verlag .

Gladilina, V., P. Gol'din. 2014. NEW PREY FISHES IN DIET OF BLACK SEA BOTTLENOSE DOLPHINS, TURSIOPS TRUNCATUS (MAMMALIA, CETACEA). The Journal of National Academy of Sciences of Ukraine, Schmalhauzen Institute of Zoology , 48: 83-92. Accessed October 01, 2017 at https://www.degruyter.com/downloadpdf/j/vzoo.2014.48.issue-1/vzoo-2014-0009/vzoo-2014-0009.pdf .

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Kishimoto, H. 2001. Uranoscopidae, Stargazers. Pp. 3519-3531 in Bony fishes part 4 (Labridae to Latimeriidae), estuarine crocodiles, sea turtles, sea snakes and marine mammals , Vol. 6. Rome: FAO. Accessed October 01, 2017 at ftp://ftp.fao.org/docrep/fao/009/y0870e/y0870e16.pdf .

Linnaeus, C. 1767. Systema Naturae, per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, Cum Characteribus Et Differentiis . Leiden: Lugduni Batavorum. Accessed October 01, 2017 at https://ia800503.us.archive.org/8/items/mobot31753000798865/mobot31753000798865.pdf .

Pavlov, D., A. Kasumyan. 2002. Feeding Diversity in Fishes: Trophic Classification of Fish. Journal of Ichthyology , 42: S137-S159. Accessed October 01, 2017 at https://www.researchgate.net/profile/A_Kasumyan/publication/264976995_Feeding_Diversity_in_Fishes_Trophic_Classification_of_Fish/links/53f9ec0d0cf20a45496ab33a.pdf .

Relini, G., M. Relini, G. Torchia. 2000. Fish population changes following the invasion of the allochthonous alga Caulerpa taxifolia in the Ligurian Sea (N-W Mediterranean) . Copenhagen: International Council for the Exploration of the Sea. Accessed October 01, 2017 at http://www.ices.dk/sites/pub/CM%20Doccuments/2000/U/U1700.pdf .

Rizkilla, S., S. Bakhoum. 2009. Some Biological Aspects of Atlantic Stargazer Uranoscopus scaber Linnaeu. Turkish Journal of Fisheries and Aquatic Sciences , 9: 59-66. Accessed October 01, 2017 at http://www.trjfas.org/uploads/pdf_730.pdf .

TEPE, Y., M. OGUZ. 2013. Nematode and acanthocephalan parasites of marine fish of the eastern Black Sea coasts of Turkey. Turkish Journal of Zoology , 37: 753-760. Accessed October 01, 2017 at http://journals.tubitak.gov.tr/zoology/issues/zoo-13-37-6/zoo-37-6-13-1206-18.pdf .

1981. Eastern Central Atlantic Fishing Area 34 and Part of 47. Pp. 267-270 in FAO Species Identification Guide for Fishery Purposes , Vol. IV. Rome: Food and Agricultural Organization of the United Nations. Accessed October 01, 2017 at http://libreria.landive.es/AG419e04.pdf .

2017. "Uranoscopus scaber Linnaeus, 1758" (On-line). Global Biodiversity information Facility Secretariat. Accessed October 01, 2017 at https://www.gbif.org/species/2394370 .