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The Virgin spinedace is primarily an insectivore (Rinse 1971, Gregor and Deacon 1988, <br />Angradi et al. 1991), and its feeding habits are dependent on food availability. Angradi et <br />al. (1991) found that spinedace fed continuously throughout the day. Spinedace position <br />themselves in the midwater column and rise to the surface to feed on floating plant material, <br />aquatic and terrestrial invertebrates (primarily dipteran and coleopteran larvae), and debris <br />(Rinse 1971, Rinse and Minckley 1991) . The amount that each food category is eaten is <br />dependent on season and size of fish. However, Rinse (1971) found that when the fish fed <br />predominantly on plant material they were in poor physical condition. <br />Virgin spinedace generally live about three years and are sexually mature at one year of age. <br />Rinse (1971) reported that in the Santa Clara River spinedace spawn from April to June at <br />mean daily water temperatures of 13 to 17°C (55 to 63°F) with maximum temperatures at <br />21 °C (70°F), and when photoperiod was greater than about 13 hours/day. Additionally, <br />peak spawning was closely correlated with peak discharge. Spawning occurs at depths of 15- <br />30 cm (5-12 in) over gravel and sand substrates at the shallow downstream end of deep pools <br />where a single female deposits eggs that are fertilized by several males. As with many <br />fishes, the important factors controlling spawning appear to be photoperiod and temperature. <br />Rinse (1971) found that one year old fish had the lowest mean relative fecundity with an <br />average of 459 eggs, while two year olds averaged 788 eggs, and three year olds averaged <br />693 eggs. Although two and three year old females produced a greater number of eggs than <br />one year olds, the two and three year olds often represented less than 10 percent of the <br />population. <br />23 <br />