DAO 116:165-172 (2015)  -  DOI: https://doi.org/10.3354/dao02916

Ichthyotoxicity of the microalga Pseudochattonella farcimen under laboratory and field conditions in Danish waters

Nikolaj Gedsted Andersen1,*, Per Juel Hansen1, Kirsten Engell-Sørensen2, Louise Hjorth Nørremark2, Per Andersen3, Ellen Lorenzen4, Niels Lorenzen

1Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
2Fishlab, Terp Skovvej 107B, 8270 Højbjerg, Denmark
3Orbicon A/S, Jens Juuls Vej 18, 8260 Viby J, Denmark
4Dept. of Animal Science, Aarhus University Denmark, Hangøvej 2, 8200 Århus N, Denmark
*Corresponding author:

ABSTRACT: Blooms of the marine dictyochophyte Pseudochattonella farcimen have been associated with fish kills, but attempts to verify ichthyotoxicity of this microalga under experimental conditions have not been successful. In the early spring of 2009 and 2011, P. farcimen bloomed in the inner Danish waters. The blooms occurred at a seawater temperature of ~2°C and correlated with extensive kills of farmed salmonid fish (2009) and wild populations (2011). Several strains of P. farcimen were isolated from the 2009 bloom. However, exposure of rainbow trout Oncorhynchus mykiss to laboratory-grown P. farcimen cultures did not reveal any toxic effects. During the 2011 bloom, fish were exposed to bloom water under both laboratory and field conditions. While no clinical effect was observed on fish incubated in bloom water in the laboratory trial, a remarkable difference was seen in the field trial between rainbow trout kept in tanks supplied with a continuous flow of filtered versus non-filtered bloom water. Histological examination of the gill tissue revealed karyorrhexis and epithelial loosening in the affected fish. Microscopy analysis of algal cell morphology suggested that mucocysts detected on the cell surface only in freshly sampled bloom water might be associated with ichtyotoxicity.


KEY WORDS: Pseudochattonella farcimen · Dictyochophytes · Ichthyotoxicity · Mucocysts · Harmful algae


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Cite this article as: Andersen NG, Hansen PJ, Engell-Sørensen K, Nørremark LH, Andersen P, Lorenzen E, Lorenzen N (2015) Ichthyotoxicity of the microalga Pseudochattonella farcimen under laboratory and field conditions in Danish waters. Dis Aquat Org 116:165-172. https://doi.org/10.3354/dao02916

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