Biofiltração da água e tipos de substrato na larvicultura do pacamã

Abstract

cinco tratamentos e cinco repetições, durante 16 dias. Para íon amônio, nitrito, nitrato e ortofosfato, houve interação entre sistemas x dias de cultivo. Os sistemas SF, CMe e CB registraram menores concentrações de íon amônio e nitrito; o sistema SB, maiores concentrações de íon amônio e menores concentrações de nitrato; o SF, concentrações de ortofosfato superiores. A sobrevivência de L. alexandri foi inferior no SF. O crescimento não foi afetado pelos diferentes sistemas. Os biofiltros melhoraram a qualidade da água quanto aos compostos nitrogenados em função do tipo de substrato.Termos para indexação: Artemia, Lophiosilurus alexandri, qualidade da água, resíduo orgânico, sistema de recirculação de água. Water biofilter system and biofilter media on pacamã larvicultureAbstract -The objective of this work was to investigate the use of different biofilter systems and biofilter media on water quality and performance of Lophiosilurus alexandri larvae. The treatments used were: no biofilter system (SB); internal biofilter with 1.6 cm average diameter shingle media (CMe); internal biofilter with 2.1 cm average diameter shingle media (CMa); a mix of 70% of grit (1.3 cm average diameter) and 30% of shell media (1.1 cm average diameter) (CB); and a closed recirculating system with external biofilter with 70% grit and 30% shell media (SF). The experiment was carried out in a completely randomized design, with five treatments and five replicates, during 16 days. Interaction between the rearing systems x rearing days affected the ammonium ion, nitrite, nitrate and orthophosphate concentrations. The SF, CMe and CB systems showed lower ammonium and nitrite concentrations; the SB system, higher ammonium ion concentrations and lower nitrate concentrations; the SF system, higher orthophosphate concentrations. L. alexandri survival was worst in the SF system. Fish growth was not affected by the different systems used. The biofilters provide better water quality in terms of nitrogenous waste depending on the biofilter media.

Effect of daily Artemia nauplii concentrations during juvenile production of Lophiosilurus alexandri

“…Nevertheless, despite the high ammonium ion levels registered in the higher Artemia nauplii concentrations, the animal performance was not negatively affected. These results corroborate with other studies which registered L. Alexandri capacity in tolerating high levels of nitrogen compounds (CARDOSO et al, 1996;LUZ and SANTOS, 2008;SANTOS and LUZ, 2009;PEDREIRA et al, 2009). This fact can be considered another positive aspect in this species choice.…”

“…Some researches focusing on the juvenile production using Artemia nauplii has been done with success for this species (LUZ and SANTOS, 2008;PEDREIRA et al, 2008PEDREIRA et al, , 2009SANTOS and LUZ, 2009;LUZ et al, 2011).…”

Larviculture of two neotropical species with different distributions in the water column in light- and dark-colored tanks

“…Water quality parameters (Table 2) were similar to those observed by other authors for the culture of larvae of pacamã (Pedreira et al, 2008a;Pedreira et al, 2009) and curimatá-pioa , and were similar between treatments, not interfering with the observed differences. The luminosity (L*) differed between tanks with different colors, which influenced the development and survival of pacamã and curimatá-pioa larvae alike.…”

Effect of water temperature and prey concentrations on initial development of Lophiosilurus alexandri Steindachner, 1876 (Siluriformes: Pseudopimelodidae), a freshwater fish

“…This practice improves Artemia nauplii consumption by fish larvae. These prey concentrations were chosen based on previous studies for L. alexandri larvae (Pedreira et al, 2009). In order to feed the larvae, Artemia cysts were hatched daily.…”