Growth and Reproduction of Yearling Tilapia Aurea in Iowa Ponds

Tilapia aurea were introduced in three Iowa ponds with the knowledge that they would not overwinter. Differential growth of the sexes and aggressive behavior interfered with tests on effects of crowding tilapia in pens. Females began reproducing at 31 g in mid-July and offspring were up to 179 mm total length or 82 g in October. Stomachs were usually empty in females brooding eggs, and condition factors were lower for females brooding fry than for other females. Males grew faster and had higher condition factors than females. Yearling tilapia 89-162 mm total length in May, added an average of 0.86 to 2.71 g per day from June 1 to early September in the 3 ponds. In Bailey\u27s Pond, the population in late September was estimated at 1450 kg of black bullheads, 37 kg of channel catfish, and 550 kg of tilapia per hectare