Controlled Spawning of Longnose Darters

Temperature (5–25°C) and photoperiod (daylight of 10–14 h) were manipulated to induce spawning in groups and individual pairs of longnose darters Percina nasuta. The fish were maintained in tanks for up to 6 years and were fed blackworms, zooplankton, and aquatic insects harvested from hatchery ponds. The fish were spawned four times between June 1994 and February 1996. Eight females released over 3,400 eggs, of which 73% were deposited on Spawntex mats. Various incubation methods were used, and 706 fry (20% hatch) were produced. Fry were offered brine shrimp Artemia sp., copepods, and cladocerans (0.053–0.212 mm in diameter) and rotifers (0.053–0.106 mm in diameter) under various culture conditions. Mortality of fry was 100% within 9 d.