DAO 54:55-60 (2003)  -  doi:10.3354/dao054055

Toxicity of anti-fouling biocides to Parorchis acanthus (Digenea: Philophthalmidae) cercarial encystment

N. J. Morley1,*, K. M. Y. Leung1,2, D. Morritt1, M. Crane1

1School of Biological Sciences, Royal Holloway, University of London, Egham TW20 0EX, United Kingdom
2Swire Institute of Marine Science and Department of Ecology and Biodiversity, The University of Hong Kong, Hong Kong SAR

ABSTRACT: The toxicity of the anti-fouling biocides tributyltin (TBTO), copper, and Irgarol 1051 (irgarol) at nominal concentrations ranging from 10 to 10000 µg l-1 was investigated against the speed of encystment and successful formation of a protective cyst of the cercariae of Parorchis acanthus. For all biocide exposures, cercariae had a much slower rate of encystment and reduced cyst formation than controls. Exposure of the snail host Nucella lapillus for 7 d caused complete cessation of cercarial shedding in irgarol-exposed snails but had no effect on cercarial encystment from TBTO and copper-exposed snails. The mechanisms of toxicity of the biocides are briefly discussed.

KEY WORDS: Parorchis · Nucella · Cercariae · Encystment · Tributyltin · Copper · Irgarol 1051

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