Induced reproduction and reproductive characteristics of Rhinelepis aspera Agassiz, 1829 (Osteichthyes: Siluriformes, Loricariidae)

Abstract

Rhinelepis aspera is the largest Loricariidae species found in the São Francisco river basin where it is now rarely caught. Brooders kept in tanks were hypophysed with crude carp pituitary extract (CCPE). Approximately 82% of the females responded positive to the treatment. The egg was opaque, demersal, round, yellow and adhesive. Egg stripping was done at 212 hour-degrees (= 8.2 h) after application of the second dose of CCPE (water temperature = 25-26°C). Hatching of the larvae occurred at 1022 hour-degrees (= 42.2 h), after fertilization of the eggs (water temperature =24-25°C). Fertilization rate of the eggs was 72%. Absolute fecundity (AF), initial fertility (IF) and final fertility (FF) in relation to the females' body weight are expressed, respectively, by the equations: AF = - 33993 + 122308 Wt (r2 = 0.88), IF = - 14823 + 58619 Wt (r2 = 0.71) and FF = -6553 + 29741 (r2 = 0.61) © 1998, Paraná Institute of Technology Publication.