Wednesday July 20, 2011

The growth an individual fish can depend on many factors, including the water temperature, the amount of food available, and the sex of the fish. Accordingly, the growth rate of hitch (Lavinia exilicauda), a native Californian cyprinid, varies throughout the state. In Clear Lake hitch can reach 40-50 mm fork length (FL) by 3 months of age (Geary and Moyle 1980), whereas at higher elevation in Beardsley Reservoir they do not reach this length until the end of their first year (Nicola 1974, as cited in Moyle 2002).  By the end of their second year in Clear Lake a hitch will be between 150-300 mm FL, in contrast a hitch in Beardsley will only have grown to be 90-110 mm FL. These differences may attributed to temperature or the productivity of the lake systems (Geary and Moyle 1980). Additionally, female hitch throughout the state grow faster than males, so at a comparable age, females will be larger. Although, male hitch can mature by Age 1, while females mature by the end of their 3rd year (Murphy 1948). While this type of information may seem unexciting or trivial, life history information is vital to understanding and managing populations of fish.

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