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Effects of acute and chronic toxicity of unionized ammonia on mud crab, Scylla serrata (Forsskål, 1755) larvae
Author(s) -
Neil Luke L,
Fotedar Ravi,
Shelley Colin C
Publication year - 2005
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.1365-2109.2005.01304.x
Subject(s) - scylla serrata , ammonia , biology , moulting , larva , zoology , prawn , fishery , toxicology , ecology , biochemistry
While the effects of ammonia on fish and prawn larvae are well documented, little is known of its effect on mud crab ( Scylla serrata ) (Forsskål, 1755) larvae. Two experiments were conducted in 5 L hemispherical plastic bowls, containing 3 L of ultra‐filtered and settled seawater and various larval stages of mud crab to (1) determine the acute median lethal concentration (LC 50 ) of unionized ammonia and (2) to determine the chronic effects of unionized ammonia on survival and percentage moulting to zoea and megalop stages. The larval stages that exhibited the highest tolerance to ammonia over 24 h were zoea 1 (LC 50 of 4.05 mg L −1 of unionized ammonia) and zoea 5 (LC 50 of 6.64 mg L −1 of unionized ammonia). The megalop stage had the lowest total ammonia LC 50 at both 24 and 48 h, making it the larval stage most susceptible to total ammonia. Exposure to 6.54 mg L −1 of unionized ammonia resulted in 100% death of all larvae within 24 h. The tolerance of S. serrata larvae to total ammonia did not appear to increase with ontogenetic development. The results indicate that the concentrations at which total ammonia produces an acute or chronic response in mud crab larvae are far higher than those experienced in current larval production systems (0–0.5 mg L −1 of total ammonia) used as industry standards in Australia.