 Splittail(Pogonichthys macorlepidotus)
 Distribution of Splittail in San
Francisco Bay
Splittail are somewhat large (40 cm FL) Cyprinids endemic to the Sacramento and
San Joaquin river systems and other drainages of San Francisco Bay. Historically,
splittail inhabited all valley portions of the Sacramento and San Joaquin river
systems. Presently their upstream range is restricted by permanent dams and
diversions. Splittial spawn in the late winter, spring and early summer. They spawn
in freshwater portions of the Delta, the lower Sacramento and San Joaquin rivers and
possibly other rivers. Splittail spawn adhesive eggs which are believed to be laid
on aquatic and flooded terrestrial vegetation. Young remain near shore initially,
then move to deeper water with growth. Year class strength, as measured by trawl
sampling in the Delta, is positively related to freshwater outflow during the spawning
season. After spawning, adults appear to return to the Delta, Suisun Bay and Suisun
Marsh to forage during the summer and fall. Some portion of the young-of-the-year
population also migrates to the Delta. Splittail of both sex mature at age-2, with
some males maturing as early as age-1 and some females as late as age-3. They are
believed to live up to seven years, spawning annually once mature. Splittail are
eaten by striped bass and Sacramento squawfish. They also support a recreational
fishery near the city of Sacramento during the winter.
Annual abundance indices for the
juveniles is generated by the Midwater Trawl Survey.
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