CONTROLLED SPAWNING OF LONGNOSE DARTERS

Temperature (5-25 degrees C) and photoperiod (daylight of 10-14 h) wer e manipulated to induce spawning in groups and individual pairs of lon gnose 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 betwee n June 1994 and February 1996. Eight females released over 3,400 eggs, of which 73% were deposited on Spawntex mats. Various incubation meth ods were used, and 706 fry (20% hatch) were produced. Fry were offered brine shrimp Artemia sp., copepods, and cladocerans (0.053-0.212 mm i n diameter) and rotifers (0.053-0.106 mm in diameter) under various cu lture conditions. Mortality of fry was 100% within 9 d.