Cymatogaster aggregata Gibbons 1854

Shiner perch swim primarily using their pectoral fins, which is called labriform swimming. One pectoral fin beat cycle is comprised of three phases: (1) abduction, when the fins are moving away from the body; (2) adduction, when the fins are moving towards the body; and (3) the refractory period, when the fins are tucked against the body.

Thrust and lift forces are generated during both abduction and adduction. The proportion of the fin cycle occupied by these two phases increases as the fish swims faster; accordingly, the proportion occupied by the refractory period decreases. Both frequency and amplitude of the fin beat increase as the fish swims faster (Webb 1973).

Shiner perch also show evidence of synchronizing mouth opening for ventilation with adduction (Webb 1975).

Distinguished by the rather deep, compressed body, the large scales, and the three spines in the anal fin (Ref. 27547). Lateral line slightly arched, complete (Ref. 27547). Generally silvery, with back dusky to greenish; middle of sides toward head are scales with groups of fine black dots on them, forming about eight longitudinal stripes; the stripes are often interrupted, especially in females, by three pale yellow, vertical bands; paired fins colorless; dorsal and caudal fins plain or dusky; anal fin usually colorless, sometimes with a yellow blotch toward the front (Ref. 27547). Breeding males may be almost solid black and develop fleshy lobes on both sides of anal fin (Ref. 27547).

Viviparous. Mating is preceded by courtship. The male moves slowly toward the female, who retreats. Her flight stimulates pursuit by up to 10 males. During the pursuit, males attempt to bring their anal regions in contact with that of the female. One male heads off the female, urging her away from the group of males and also driving them away. The female is conducted to the shelter of a rock or other object, where the courtship dance begins. In this dance, the male, with dorsal fin fully erect, swims by means of his pectoral fin in a figure eight pattern over the female, udulating in both the horizontal and vertical planes. The male then stops, faces the female head to head, quivers, then moves his jaws and undulates his dorsal fin. He then moves beside the female, facing in the same direction, and repeats the movements. Finally, the male tilts on his side, the female tilts slightly away from hin, and the anal regions are brought in contact with each other. Copulation lasts less than a second. Gestation takes five to six months. Bears 3 to 36 young. Female carries the developing young (Ref. 205). Males are mature and ripe at birth. Juvenile females are mated soon after being born (Ref. 27547).

Dorsal spines (total): 8 - 11; Dorsal soft rays (total): 19 - 22; Analspines: 3; Analsoft rays: 22 - 25; Vertebrae: 33 - 37

Feeds on zoobenthos and plants (Ref. 27547).

Usually in shallow water, around eelgrass beds, piers and pilings and commonly found in bays and quiet back waters (Ref. 2850). Also in calm areas of exposed coast (Ref. 2850). Enter estuaries and brackish waters (Ref. 114138) [noted from freshwaters in Ref. 2850, but it is unlikely or rarely]. Found in loose schools or aggregations (Ref. 2850, Ref. 114138). Young feed mainly on copepods, while adults eat various small crustaceans, mollusks, and algae (Ref. 27547). Viviparous, female carries the developing young (Ref. 205). Exhibit seasonal onshore-offshore movements (Ref. 27547).

fisheries: minor commercial; gamefish: yes; bait: occasionally; price category: unknown; price reliability:

The shiner perch (Cymatogaster aggregata) is a common surfperch found in estuaries, lagoons, and coastal streams along the Pacific coast from Alaska to Baja California. It is the sole member of its genus. The shiner perch is also known as seven-eleven and shiner seaperch.

Dissected pregnant female

Shiner perches are similar to tule perches, deep-bodied with a dusky greenish back and silvery sides that have a pattern combining fine horizontal bars with three broad yellow vertical bars. Breeding males turn almost entirely black, the barred pattern being obscured by dark speckles. Shiner perches are distinguished from tule perches by having fewer dorsal fin spines, just 8–9 vs the 15–19 of the tule perch. The rayed part of the dorsal fin has 18 to 23 rays. The anal fin has 3 spines followed by 22–25 rays.

They are one of the most common fish in the bays and estuaries of their range, favoring beds of eelgrass, and often accumulating around piers as well. They feed on zooplankton such as copepods, but have been observed to bottom feed as well.

They are often found with parasitic isopods such as the Elthusa californica feeding off of them from their opercular cavity of the gill chamber.