The effect of water pH on the incubation and larviculture of curimbatá Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae)

Abstract

Different pH levels of water in the incubation and larviculture of 'curimbatá' (Prochilodus lineatus) were tested to evaluate the effect of this variable on the survival and development of eggs and larvae. During incubation, pH of 5.0, 6.0, 7.0, 8.0, and 8.5 was tested. To observe the effects of pH on larvae with different hatchery histories, the following experimental design was utilised (pH incubation - pH larviculture): L 6-6; L 6-7; L 7-6; L 7-7; L 7-8; L 8-7; L 8-8; L 8.5-7, and L 8.5-8.5. At pH 5.0 and four hours after incubation, an almost total mortality of incubated eggs was seen. Eggs incubated at pH 6.0 to 8.5 had similar fertilization and survival rates at the end of incubation, although eggs and larvae incubated at pH 6.0 had a smaller diameter and total length than larvae incubated at neutral and alkaline pH. During larviculture, it was observed the highest post-larvae survival rates with incubation at pH values of 7.0 (93 ± 7%) and the largest post-larvae lengths from the L 8.5-7 treatment (9.29 ± 0.8 mm). It can be concluded that hatchery and larviculture pH directly affects the initial developmental stages of P. lineatus.