About Atherina boyeri Risso, 1810
Atherina boyeri Risso, 1810 is a small pelagic fish species that lives near the surface in the littoral estuarine zone, including lagoons, salt marshes with 77 psu salinity, shallow brackish areas with 2 psu salinity, and inland waters that are too high in ionic strength and salinity to support most other fish species. Its body is relatively long, slender, and moderately flattened, with large eyes. Both the head and body are covered in scales. The mouth is protractible, oriented upward, and lined with small teeth. The lower jaw has an upper expansion inside the mouth, formed by a high dentary bone. This species has two separate dorsal fins; all rays of the first dorsal fin, and the 1–2 anterior rays of the second dorsal fin, are unsegmented. The first dorsal fin has 6–10 flexible spines. The anal fin has a similar structure to the second dorsal fin, and the caudal fin is forked. It is an omnivorous species that feeds on zooplankton and small bottom-dwelling animals, specifically gammarid crustaceans, polychaete worms, and molluscs. Its range extends across the eastern Atlantic Ocean from Portugal and Spain south to Nouadhibou, Mauritania, and also includes Madeira. It also lives throughout the Mediterranean Sea, including in inshore lagoons such as Trasimeno and Lesina in Italy, Hyères near Marseille in southern France, and Lake Qarun in Egypt. An isolated population occurs near the coasts of England and the Netherlands. In the Black Sea, it is widespread across all coasts, in lagoons and estuaries, and in the downstream reaches of the Danube, Dniester, Southern Bug, Inhulets, and Dnieper rivers; a permanent population lives in the Kakhovka Reservoir. The isolated population found in the Caspian Sea is classified as the subspecies A. b. caspia (Eichwald, 1838).
