Diplodus argenteus
Diplodus argenteus, the silver porgy, is an ocean-going species of sparid fish (seabream/porgies) in the genus Diplodus. It is also called the South American silver porgy and the white bream in Uruguay, plus the silver seabream and the sargo though the latter three names are also used for other fish species as well.Nión, H., C. Ríos and P. Meneses, 2002. Peces del Uruguay: Lista sistemática y nombres comunes. Montevideo, DINARA, Infopesca.

Taxonomy and naming
The silver porgy was originally desrcibed in 1830 by the French zoologist Achille Valenciennes as Sargus argenteus, but it was later moved from the genus Sargus into Diplodus. Fricke, R., D. Golani and B. Appelbaum-Golani, 2016. Diplodus levantinus (Teleostei: Sparidae), a new species of sea bream from the southeastern Mediterranean Sea of Israel, with a checklist and a key to the species of the Diplodus sargus species group. Scientia Marina 80(3):1-16.Cuvier, G. and A. Valenciennes  1830 (Sept.) Histoire naturelle des poissons. Tome Sixième. Livre sixième. Partie I. Des Sparoïdes; Partie II. Des Ménides. v. 6: i-xxiv + 6 pp. + 1-559, Pls. 141-169. [Valenciennes is author of pp. 1-425, 493-559; Cuvier 426-491. i-xviii + 1-470 in Strasbourg ed.] Another binomial name, Sparus sargo, was erected by Dámaso Antonio Larrañaga in 1923 to describe fishes that are now considered to be silver porgies as well, meaning that Sparus sargo is considered a junior synonym for D. argenteus.  Larrañaga, D. A.  1923 Escritos de Don Dámaso Antonio Larrañaga. Los Publica el Instituto Histórico y Geográphico del Uruguay. Edición Nacional. v. 2: 1-512 [Atlas published in 1930. See also Devincenzi 1925 

Etymology
The genus name, Diplodus means "double toothed", a description which was not well-explained, but may have been done in reference to the species' two types of teeth: incisor-like and molar-like, or to the double incisor-like tooth shape common to this genus. The species name argenteus comes from the Latin word for silver, which is a reference to the fish's coloration, rather than its origin near Argentina, or anything to do with Argentina's etymology.

Description
As its name suggests, this D. argenteus''' silvery coloration (often with a yellowish tint on the scales and fins) is a significant characteristic of its appearance.  Wells, V. Carpenter, C. 2011. A Field Guide to Coastal Fishes from Maine to Texas. Baltimore. Johns Hopkins University Press. In addition to its main coloring, there are nine dark, narrow bars that can be faintly visible on the anterior portion of its body (especially in younger individuals, as they fade with age), there is also a large, black blotch on the caudal peduncle, and the opercular membrane is also very dark in color. Chute, W. 1953. Guide to the John G. Shedd Aquarium. 4th edition, 4th printing. Pg. 114-115 Randall, J.E., 1996. Caribbean reef fishes. Third Edition - revised and enlarged. T.F.H. Publications, Inc. Ltd., Hong Kong. 3nd ed. 368 p. The silver porgy's dorsal fin is made up of 12 spines, and 13-15 soft rays; it's anal fin is consists of only 3 spines, but 12-14 soft rays. Mature silver porgies achieve about 20 to 23cm in length, while the maximum known length for this species is 37.8cm in length and the largest weight reported was 2.5kg.David, G.S., R. Coutinho, I. Quagio-Grassiotto and J.R. Verani, 2005. The reproductive biology of Diplodus argenteus (Sparidae) in the coastal upwelling system of Cabo Frio, Rio de Janeiro, Brazil. Afr. J. Mar. Sci. 27(2):439-447.

Distribution and habitat
The silver porgy is known primarily from the western Atlantic Ocean, where it can be found in the waters of southern Florida as well as the Antilles and Bahamas.Smith, C.L., 1997. National Audubon Society field guide to tropical marine fishes of the Caribbean, the Gulf of Mexico, Florida, the Bahamas, and Bermuda. Alfred A. Knopf, Inc., New York. 720 p. Along the coast of South America, it is known from coasts of Colombia and Venezuela to Argentina - as far south as the coast of northern Patagonia.Galván, D. E., Venerus, L. A., Irigoyen, A. J., Parma, A. M., & Gosztonyi, A. E. (2005). Extension of the distributional range of the silver porgy, Diplodus argenteus (Valenciennes 1830), and the red porgy, Pagrus pagrus (Linnaeus 1758)(Sparidae) in northern Patagonia, south-western Atlantic. Journal of Applied Ichthyology, 21(5).Randall, J.E. and R. Vergara, 1978. Sparidae. In W. Fischer (ed.) FAO species identification sheets for fishery purposes. Western Central Atlantic (Fishing Area 31). FAO, Rome. Vol. 5. pag.var. They are also found in the Bay of Campeche, which is part of the Gulf of Mexico.  They can even be found in the waters around Bermuda, but are not especially common. 
thumb|left| 300px|Seagrass beds such as this one in the Caribbean Sea often inhabited by subadult silver porgies.

Adult silver porgies usually inhabit clear but turbulent waters over rocky or coral bottoms, especially on unsheltered coasts that are heavily affected by surf. Robins, C.R. and G.C. Ray, 1986. A field guide to Atlantic coast fishes of North America. Houghton Mifflin Company, Boston, U.S.A. 354 p. Juveniles, on the other hand, can be found in much shallower water, such as in pools between rocks, though mid-sized individuals up to 10cm can be also found in beds of seagrass from the genus Thalassia.'' Cervigón, F., 1993. Los peces marinos de Venezuela. Volume 2. Fundación Científica Los Roques, Caracas,Venezuela. 497 p.

Biology
Silver porgies eat mostly shellfish especially crustaceans and mollusks, however the remains of algae and polychaete worms have also been found in the stomachs of specimens collected from the Brazilian coast. 

Relationship with humans
The silver porgy is fished commercially, but only traded locally. Able to be caught via angling or through trapping, it makes up a major portion of the catch in the Cabo Frio region of Brazil, but is generally caught incidentally, and is even reported rare from fisheries in other parts of its range such as Cuba. Catches are generally very small and come from Argentina, Brazil, and Uruguay, through fishing for this species off the United States East Coast and Brazil once dominated the silver porgy catch for most of the late 20th Century. 

Because of its habitat and distribution, this species is often encountered by recreational SCUBA divers and snorklers.  Despite its fairly high probably of being encountered in certain ecosystems, the silver porgy is seldom approaches divers, and generally moves away from divers when approached.

References

External links
IUCN RedList Entry
FishBase.org Entry

Category:Sparidae
Category:Fish described in 1830
Category:Taxa named by Achille Valenciennes
Category:Fish of the Caribbean
Category:Fish of South America
Category:Fish of the Atlantic Ocean