How to Identify Jacksmelt

To identify Jacksmelt (Atherinopsis californiensis), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Dorsal surface is typically olive-green to bluish-gray, fading to silvery on the sides and ventral surface. A prominent, iridescent silver stripe runs laterally along the body, from the operculum to the caudal fin base. Fins are generally translucent or dusky.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Two widely separated dorsal fins, the first with flexible spines and the second with a spine and soft rays., A small, terminal mouth with small, conical teeth., Large eyes., A prominent lateral silver stripe.

Dorsal fin

First dorsal fin with 5-9 flexible spines; second dorsal fin with 1 spine and 9-14 soft rays. The two dorsal fins are distinctly separated.

Tail fin

Moderately forked caudal fin.

Pectoral fin

Pectoral fins are relatively high on the body, with 13-17 rays.

Distinctive fins

Pelvic fins are abdominal, located well behind the pectoral fins, with 1 spine and 5 soft rays. Anal fin has 1 spine and 21-27 soft rays.

Identification Tips

1. 1

   Body Shape and Coloration

   Look for the elongated, slender, silvery body with a distinct iridescent silver stripe along the side. The back is darker (olive-green to bluish-gray).

2. 2

   Dorsal Fins

   Note the two widely separated dorsal fins. The first is spiny, and the second is soft-rayed. This is a key differentiator from many other 'smelt-like' fishes.

3. 3

   Mouth

   The mouth is small and terminal, not extending past the anterior margin of the eye.

4. 4

   Size

   Jacksmelt are relatively large for a silverside, commonly reaching 25-35 cm (10-14 inches) and up to 45 cm (18 inches) in length.

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