Sensitivity of four New Zealand cladoceran species and Daphnia magna to aquatic toxicants

Abstract

Four New Zealand cladoceran species (Daphnia carinata, Simocephalus vetulus, Ceriodaphnia dubia, and Ceriodaphnia cf. pulchella) were compared with Daphnia magna for their acute (short‐term) and chronic (long‐term) sensitivity to toxicants. In acute tests with 5 reference toxicants and 2 effluent samples (chromium (Cr⁶⁺), pentachlorophenol, boron, fluoride, biocide (Alfloc 324), kraft bleach effluent pond, and a geothermai discharge), C. dubia was more sensitive than D. magna by up to a factor of 4. In chronic tests on 4 toxicants no differences in sensitivity were observed within 1 order of magnitude. Acute: chronic ratios ranged from 1.3 to 13.5. C. dubia is recommended as a routine test organism because of its good laboratory growth and higher sensitivity than D. magna. D. carinata would also be suitable, but both S.vetulus and C. cf. pulchella showed poor laboratory performance.

Key words:

• aquatic
• toxicity
• cladocerans
• zooplankton
• Daphnia magna