102.
Ammonia toxicity tests were performed with
Labeo bata (bata) larvae of three different size groups. One hundred percent survival of larvae (500.0?±?4.0?mg) was recorded when exposed to ammonia concentrations of 1.0–13.56?mg?L
?1 at 96?h of exposure. Bata larvae exposed to ammonia concentrations of 15.8–25?mg?L
?1 showed 10–74% mortalities. The 96?h LC
50 value for 200 (±5), 250 (±2) and 500 (±4) mg bata larvae were 11.5, 16.8 and 22.5?mg?L
?1 un-ionised ammonia concentrations, respectively. When fish were exposed to different doses of ammonia, behavioural changes immediately occurred even at the lowest dose. At first, the fish became hyperexcitable, the skin darkened and they showed an increased ventilation frequency, fish behaviour became normal, 24?h after exposure. A 96?h LC
50 value of un-ionised ammonia showed direct relationship with the increasing size of bata larvae.
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