Acute ammonia toxicity during early ontogeny of chub, Leuciscus cephalus (Cyprinidae)

¹ Department of Ichthyology, University of Warmia and Mazury, Oczapowskiego 2, 10-917 Olsztyn, Poland
² Department of Lake and River Fisheries, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, pok.325, 10-957 Olsztyn, Poland

^a Corresponding author: pgomulka@uwm.edu.pl

Received: 21 October 2010
Accepted: 4 May 2011

Abstract

Acute toxicity of ammonia was investigated in four life stages of juvenile chub, Leuciscus cephalus (cyprinid fish): 1, 10, 20 and 30 days after the first feeding. The fish used for the toxicity test were reared intensively in a closed recirculation system. Each acute toxicity test duration was 96 h and lethal concentration LC₁, LC₅₀ and LC₉₉ values were calculated for 24, 48, 72 and 96 h. The susceptibility of chub to acute ammonia toxicity decreased linearly with age and stage of development. The LC₅₀ (48 h) values ranged from 0.62 mg L^-1 of unionized ammonia nitrogen for one day after first feeding larvae to 1.73 mg L^-1 for 30 days after first feeding ones. A significant linear relationship between chub larvae susceptibility to ammonia toxicity and both body weight and length was found. The critical level of unionized ammonia nitrogen for chub larvae was suggested as 0.49 mg L^-1.