Slightly saline water increases the larviculture efficiency of freshwater Neotropical fish

Abstract

The objective of this work was to evaluate the effect of slightly saline water in an intensive larviculture of tambaqui, matrinxã, apaiari, and piau, during the initial days of active feeding. Larvae were reared in artificial saline water, at concentrations from 0 (freshwater) to 14 g L^‑1 NaCl (at a 2.0 g L^‑1), and fed with two portions of Artemia nauplii, following a specific protocol for each species, in a completely randomized design, with 3 replicates. Tambaqui, matrinxã and apaiari larvae can be reared at saline concentrations till 2 g L^‑1 without impairing growth and survival. Piau larvae were more tolerant and endured saline water until 4 g L^‑1. At saline concentrations above that, fish mortality increased and reached 100% at 6 g L^‑1, for matrinxã and apaiari, and at 10 g L^‑1, for tambaqui. Saline water at 2 g L^‑1 provided a higher survival for matrinxã, and higher growth for tambaqui, apaiari and piau. These last two species showed a better growth performance with the highest quantity of nauplii. Slightly saline water at 2 g L^‑1 is beneficial to these studied species, as it optimizes larval growth potential and the use of Artemia nauplii as live food.