 Shiner Perch (Cymatogaster aggregata )
 Distribution of shiner surfperch in San
Francisco Bay
Shiner perch range from Baja California to Port Wrangell, Alaska. Shiner perch are
common in bays around eel grass beds and pilings and along the open coast in protected
areas. In the Bay, they are most abundant in the shallow areas of South, Central, and
San Pablo bays. Juveniles are polyhaline; most collected by this study were from
salinities greater than 20‰. Shiner perch live to eight years and reach a maximum
length of approximately 178 mm. A small bait fishery exists for shiner perch, but
otherwise they are not commercially important. Due to their small size, they are a
minor component of the Bay's sportfishery.
As with all Embiotocids, shiner perch are viviparous. Mating occurs in the spring and
summer and females store sperm until winter, when fertilization takes place.
Development of the young takes approximately six months, with parturition usually
occurring in June or July. Females immigrate from nearshore coastal waters to the
Bay prior to giving birth. Soon after birth, males mature and emigrate to the ocean,
while most females spend their first year in the Bay and give birth before emigrating
to the ocean.
Shiner perch are omnivores, preying upon algae, copepods, amphipods and polychaetes.
They are eaten by many species of larger marine fishes, including sturgeon, salmon
and striped bass. They are also important prey for harbor seals and piscivorous birds
such as cormorant.
Abundance indices of young-of-the-year (YOY) shiner perch have been low since 1988,
with relatively little variation in the annual indices the other years. As for
walleye surfperch, low fecundity combined with a seasonal migration shallow waters
may make shiner perch vulnerable to overfishing, although they are not a highly sought
after commercial or sport species due to their smaller size. Shiner perch may have
been impacted by loss of tidal marshes in the Bay, as salt and brackish marshes and
other shallow water habitats are important nursery areas. Of the estimated 200,000
acres of tidal marsh that existed in San Francisco Bay in the 1850's, approximately
36,000 acres of remain. However, most of this loss occurred prior to 1965, after
which stricter fill regulations were enforced.
Annual abundance indices for YOY shiner perch are generated
from the San Francisco Bay Monitoring Program using
otter trawl data.
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