Common names: shad (English), sábalo (Espanol), sardina (Espanol)
Dorosoma petenense (Günther, 1867)
Body deep, compressed; snout projecting, rounded; mouth small, at front, with a deep central notch between front of upper jaws, lower jaw enclosed by upper when mouth is closed; sides of lower jaw curved in below when viewed from front; ventral profile strongly convex, with complete scuted keel; last dorsal fin ray long, filamentous in adults; anal fin short, 17-27 rays, origin just behind base of dorsal fin; scales large (41-48 lateral rows), regularly arranged.
Grey-brown to blue-black above; sides silver; a black spot a little behind upper edge of operculum.
Size: 33 cm.
Habitat: common in mouths of rivers; lives in rivers and freshwater lakes.
Depth: 0-10 m.
A west Atlantic species introduced into rivers of the NE Gulf of California.