Fish Identification Photos: Jacksmelt, Atherinopsis californiensis: The Jacksmelt has a compressed head and body that is green on top, a silver stripe along the flank, and silver coloration on the sides and bottom. The head has small eyes and a short snout with an elongated mouth at the front, and the top lip folded down. The pectoral fins of the Jack Smelt are short and the gill covers are bright yellow in color.

Three keys to identification of the Jacksmelt include: size, this is the largest of the silversides; the anal fin commences well behind the end of the first dorsal fin; and the distance between the two dorsal fins is large.

The Jacksmelt is a schooling surface fish that reaches a maximum length of 18 inches and is normally found in the first 100 feet of the water column in murky waters, over sandy bottoms, and around piers. It is an active day feeder, eating algae primarily, and is quiet at night.

The Jack Smelt can be easily confused with the Topsmelt, Atherinops affinis, which is smaller in size, with a small gap between the dorsal fins, and the anal fin originating directly under the end of the first dorsal fin.

The Jacksmelt is found all along both sides of Mexico's Baja California peninsula and along the coast of the Mexican mainland north of Guaymas. It is are absent from along most of the coast of the Mexican mainland and from around Mexico's oceanic islands. In California the Jacksmelt is a major catch off piers and is a targeted commercial species deemed to be of great food value. It was a staple food item of early Native Americans.

The Jacksmelt is a member of the Atherinidae Family and of the Atherinopsis Genus, which are the Silversides. Globally, there is only one member of the Atherinopsis Genus: this species. The Silversides are small, schooling fish found inshore or over reefs. They are characterized by having two dorsal fins, the first of which has only six slender spines, long pectoral fins that are high on the body, pelvic fins with one spine ray and five rays on the abdomen, no lateral line, and a broad silver stripe on the side. They provide an excellent food source for birds, fish, and marine mammals.

Jacksmelt, Atherinopsis californiensis: Caught off the municipal pier, Oceanside, California, May 2006, in 60-degree water, on a Sabiki Rig, using size-4 hooks. Size, approximately 9 inches. Photo courtesy of John Snow.