Reproduction and fecundity of tucunaré,Cichla kelberi(Perciformes: Cichlidae), an exotic species in Três Marias Reservoir, Southeastern Brazil

Abstract

Summary To evaluate the reproductive cycle and fecundity of tucunare´ (Cichla kelberi Kullander & Ferreira, 2006), 697 specimens were captured in Tres Marias Reservoir, Sao Francisco River, Brazil during 1994-1995 and 2005-2006. Reproductive activity was recorded throughout the sampling periods, with females exhibiting asynchronous oocyte development and multiple spawnings with a peak in September-October. Vitellogenic oocytes of the tucunarewere elliptical in shape with the longest diameter approximately 1230 lm and the shortest 700 lm, yolk globules with ellipsoid inclusions, lipid vesicles, small cortical alveoli and thin zona radiata (9.3 ± 2.0 lm thick- ness). Follicular cells were prisma-shaped (49.0 ± 16.4 lm) in the vegetative pole, progressively becoming cubic cells in the animal pole toward the micropyle. Histochemical analyses indicated the presence of mucosubstances in the outer zona radiata and follicular cells that could be contributors to egg adhesiveness. Batch fecundity ranged from 4450 to 13 900 oocytes for females 31.5-43.5 cm total length, respectively, and correlated to gonadal weight (r 2 = 0.80) and body weight (r 2 = 0.70). Mean relative fecundity was 10.6 vitellogenic oocytes per gram body weight. As tucunareis an exotic piscivorous species well-adapted to the Tres Marias Reservoir, the present work may be considered a contribution toward future strategies for population control.