Growth and survival of silver catfish larvae, Rhamdia quelen (Heptapteridae), at different calcium and magnesium concentrations

Abstract

Since the relative ratios of Ca 2+ and Mg 2+ can vary greatly from one water body to another, and lime used for the increase of water hardness or pH can have different ratios of Ca 2+ and Mg 2+ in its composition, the objective of this study was to analyze the growth and survival of silver catfish, Rhamdia quelen, larvae at different calcium and magnesium concentrations. After fertilization, eggs were randomly divided into 4 treatments (three replicates per treatment) with different concentrations

Interaction of Water Hardness and pH on Growth of Silver Catfish, Rhamdia quelen, Juveniles

“…The 30-180 mg/L CaCO 3 water hardness range did not change the growth of silver catfish juveniles raised in neutral pH water. This range is wider than the 20-70 mg/L CaCO 3 water hardness range suggested for the growth of larvae of this species (Silva et al , 2005Townsend et al 2003). The juveniles kept at pH 9.0 had a better growth rate in soft water (30 mg/L CaCO 3 ), whereas a water hardness of 120 mg/L CaCO 3 reduced the deleterious effect of acidic water (pH 5.5) on growth in these fish.…”

“…Growth of silver catfish juveniles is higher at pH 7.0 compared to acidic (pH 5.5) or alkaline (pH 9.0) soft water and dietary Ca 2+ supplementation does not protect against changes in pH (Copatti et al 2005). As described previously, the effect of pH and water hardness is well studied in silver catfish larvae growth (Lopes et al 2001;Townsend et al 2003;Silva et al 2005), but juveniles are much more resistant to acute changes of pH and water hardness (Townsend and Baldisserotto 2001) and the effect of water hardness on the growth of juveniles of this species has not been investigated. Consequently, the objective of this study was to determine the optimal water hardness at different pH levels for survival and growth in silver catfish juveniles.…”

Water parameters affect anaesthesia induced by eugenol in silver catfish, Rhamdia quelen

“…Silver catfish juveniles can be transferred from soft water to solutions containing 600 mg CaCO 3 L −1 (higher levels were not tested) without mortality, and survival under very acidic or alkaline pHs is improved by the addition of Ca 2+ to the water (Townsend & Baldisserotto 2001). The best water hardness range for larval growth and survival is 30–70 mg CaCO 3 L −1 (Silva, Golombieski & Baldisserotto 2003, 2005; Townsend, Silva & Baldisserotto 2003). The mean water temperature in southern Brazil is 16–28 °C in the summer and 14–17 °C in the winter (Garcia, Copatti, Wachholz, Pereira Filho & Baldisserotto 2008), which are suitable temperature ranges for silver catfish survival and growth (Chippari‐Gomes, Gomes & Baldisserotto 1999; Piedras, Moraes & Pouey 2004).…”

Freshwater parameters in the state of Rio Grande do Sul, southern Brazil, and their influence on fish distribution and aquaculture

“…The increase of water hardness from 30 to 60 mg L -1 CaCO 3 also improved the growth of R. quelen juveniles exposed to a pH of 5.5, but decreased growth in those kept at a pH of 9.0 (Copatti et al, 2011a). Larvae of this species kept at a pH of 8.0 to 8.5 showed the highest survival and growth at both 30 and 70 mg CaCO 3 L -1 (Townsend et al, 2003), but 70 mg CaCO 3 L -1 is the best level for incubation and larviculture irrespective of the proportions of Ca 2+ and Mg 2+ used to increase water hardness (Silva et al, , 2005. Consequently, considering the water hardness, the southern region of Rio Grande do Sul is the best area for incubation and larviculture of R. quelen because at least the maximum values (except the city of Cidreira) are within the best range for this species.…”