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TOXICIDADE AGUDA DA AMÔNIA E DO NITRITO PARA JUVENIS DO PAMPO Trachinotus marginatus (CUVIER, 1832) EM DIFERENTES SALINIDADES.

by Fonseca Costa, Luiza Dy

Abstract (Summary)
The present study was conducted to estimate the acute toxicity of ammonia-nitrogen (NH3-N) and nitrite-nitrogen (NO2--N) to juvenile pompano Trachinotus marginatus(0.86 ± 0.21 g) at different salinity levels: 5, 10 (equivalent to its isosmotic point), and 30?. Fish were acclimated to the different salinities for 10 days and fed in excess daily. Groups of five fish (0.86 ± 0.21 g) were exposed to five concentrations of NH3-N and NO2--N for 96 h plus control groups for each salinity in three replicates where no toxicant was added, measured concentrations ranged from 0.28 to 3.53 mg NH3-N/L and 24.8 to 191.1 mg NO2 --N/L. Tests were run using a standard semi-static system with 100% daily renewal of water and toxicants. The results were based on mortality data registered in different concentrations tested, using the software Trimmed Spearman Karber method. The median-lethal concentrations (LC50) after 96 h of exposure to NH3-N were 0.66 (0.53-0.81), 1.87 (1.65-2.12) and 1.06 (0.94-1.20) mg NH3-N/L for 5?, 10?, and 30?. The LC50 -96 h to NO2--N were 39.94 (36.39-43.84), 116.68 (112.52-121.00) and 37.55 (20.91-67.44) mg NO2--N/L for?, 10?, and 30 ?. Acute toxicity of NH3-N and NO2--N to pompano was affected by salinity. Results of the present study show that pompano reared at an isosmotic environment are less sensitive to NH3-N and NO2- -N. Tolerance to NH3-N is compromised at reduced salinities, while toxicity of NO2--N is similar at 5 and 30 ?.
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Wilson Francisco Britto Wasielesky Junior; Luís André Nassr de Sampaio; Kleber Campos Miranda Filho; Bernardo Baldisserotto

School:Fundação Universidade Federal do Rio Grande

School Location:Brazil

Source Type:Master's Thesis

Keywords:trachinotus marginatus toxicity ammonia nitrite pompano salinity

ISBN:

Date of Publication:01/24/2008

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