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Daily variation in short‐term static toxicity of unionized ammonia in Litopenaeus vannamei (Boone) postlarvae
Author(s) -
Magallón Barajas Francisco,
Villegas Rosalía Servín,
Clark Guillermo Portillo,
Mosqueda Joaquín García,
Moreno Berenice López
Publication year - 2006
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2006.01573.x
Subject(s) - litopenaeus , shrimp , zoology , biology , ammonium , toxicity , ammonia , toxicology , fishery , chemistry , medicine , biochemistry , organic chemistry
Ammonium toxicity of short‐duration alkaline events and their variability, as related to 1–30 day‐old postlarvae whiteleg shrimp Litopenaeus vannamei (Boone), was assessed by determining medium lethal concentration (LC 50 ) of total ammonium‐nitroen (TAN) and NH 3 ‐N to 4‐h exposures. Exploratory concentrations of TAN were tested at 30°C and pH 9, until mortality from 5% to 95% occurred between 0.9 and 18 mg N L −1 . To determine the daily variation of ammonium toxicity, 64 lots of 20 postlarvae were exposed to eight different ammonium concentrations (0, 0.9, 3, 6, 9, 12, 15 and 18 mg N L −1 ), in two different environmental scenarios: α (pH 8, 26°C) and β (pH 9, 30°C). In environmental scenario α, ammonium concentrations up to 18 mg L −1 pose no short‐term mortality risks for ages 1–30 days. In scenario β, mortality was recorded at all ages. The values of LC 50 (4 h) for different postlarvae ages have daily variability, ranging from a minimum of 2.54 to a maximum of 6.02 mg L −1 of TAN (0.76 and 1.81 mg N L −1 of NH 3 ‐N), for PL 3 and PL 19 , respectively, with a logarithmic linear tendency to increase with age. Postlarvae mortality at 4 h and 3.0 mg N L −1 TAN exposure was lower and less variable in ages greater than 19 days old.