The cultivation of the lambari, Deuterodon iguape, supplies much of the Brazilian market with live bait for sport fishing. The high densities used to maximize production can increase the concentration of ammonia. In order to evaluate the sublethal and lethal effects of different concentrations of ammoniacal nitrogen (non-ionized ammonia plus ionized ammonia), D. iguape were exposed to this xenobiotic. The LC50 values for 24, 48, 72, 96 h of ammonia-N were 6.17, 5.57, 3.88 and 2.90 mg/L at 23°C. The LC50 values of 24, 48, 72, 96 h of NH3-N (non-ionized ammonia with nitrogen) were 0.015; 0.013; 0.009; 0.007 mg/L. The specific oxygen consumption increased at the ammonia-N concentrations tested. The values for the concentrations of 0.1; 0.25; 0.5 and 1.0 mg/L were: 0.25, 0.33; 0.31 and 0.44 mgO2/g/hr. At the concentration of 1.0 mg/L of ammonium chloride there was a 41.33% increase in the consumption level in relation to the control. Ammonia excretion also increased with increasing ammoniacal nitrogen concentration. The fish excreted, on average, 0.0320, 0.0364, 0.0368 and 0.0370 mg/g/h of ammonia. Comparing these results with the means of ammonia excretion of the control (0.0 mg/L), it was observed that these values represent an increase in the excretion of 146%, 177%, 189% and 184%, respectively. After 24 h of exposure to ammonia, the O:N ratio decreased by 43.46%. Our results indicate pronounced metabolic effects and increased toxicity with increasing ammonia concentrations. We recommend avoiding concentrations higher than 0.25 mg/L NH3-N in the culture water.
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Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atribuição 4.0 Internacional (CC BY 4.0). O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.
This note documents the first record of a Bryde’s whale (Balaenoptera edeni) in the South Coast Marine Environmental Protection Area (APAMLS), State of São Paulo, Brazil. This observation was made during the environmental monitoring activity of the Center, on December 7, 2016. A single specimen was sighted and photographed near the Island of Cardoso, south coast of the State of São Paulo. This species occurs between parallels of 40 ° N and 40 ° S, however, Bryde’s whale observations are still very limited on the Brazilian coast. These records represent important sources for knowing the biology and ecology of the species, besides subsidizing policies of environmental planning for the South Coast Marine (EPA).
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