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Prey preference, environmental tolerances and ichthyotoxicity by the red-tide dinoflagellate Noctiluca scintillans cultured from Tasmanian waters

Citation

Hallegraeff, GM and Albinsson, ME and Dowdney, J and Holmes, AK and Mansour, MP and Seger, A, Prey preference, environmental tolerances and ichthyotoxicity by the red-tide dinoflagellate Noctiluca scintillans cultured from Tasmanian waters, Journal of Plankton Research, 41, (4) pp. 407-418. ISSN 0142-7873 (2019) [Refereed Article]

Copyright Statement

© The Author(s) 2019.

DOI: doi:10.1093/plankt/fbz037

Abstract

The large phagotrophic dinoflagellate Noctiluca has become a prominent red tide organism in southeast Australian waters since the 2000s, raising concerns for beach tourism, grazing impacts as well as ichthyotoxicity for finfish aquaculture. Satisfactory culture growth rates (0.23–0.56 per day) were obtained by feeding with small Thalassiosira diatom and Tetraselmis flagellate diets, while optimal growth rates sustained for up to 8 months (0.69 per day) were achieved by feeding in a plankton wheel with the large chain-forming dinoflagellate Gymnodinium catenatum. Noctiluca was highly tolerant towards salinities from 20 to 35 and growth was stimulated by temperatures increasing from 10 to 23°C, which in combination with the key factor of prey abundance explains the incidence in southeast Australia of predominantly summer and spring but occasionally also winter blooms. Fatty acid biomarkers suggest that Tasmanian field populations indiscriminately feed on available diatom and dinoflagellate mixtures. Noctiluca exhibited very limited ichthyotoxicity, and only at the highest cell concentrations of 2 000 000/L (50% reduction in RTgill W1 cell viability). Only the densest red tide surface slicks contained acutely toxic levels of unionized ammonia of 242 to 510 μg/L while inshore slicks generated oxygen concentrations as low as 0–1.5 ppm. Lipid phycotoxins (eicosapentaenoic acid, docosahexaenoic acid) did not appear to contribute to Noctiluca ichthyotoxicity. The fatty acid 20:0 eicosanoic acid may serve as a potential Noctiluca biomarker in marine food webs and sediments.

Item Details

Item Type:Refereed Article
Keywords:harmful algal blooms, Noctiluca scintillans, dinoflagellate, red-tide
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Phycology (incl. Marine Grasses)
Objective Division:Environment
Objective Group:Control of Pests, Diseases and Exotic Species
Objective Field:Control of Animal Pests, Diseases and Exotic Species in Coastal and Estuarine Environments
UTAS Author:Hallegraeff, GM (Professor Gustaaf Hallegraeff)
UTAS Author:Dowdney, J (Ms Jo Dowdney)
UTAS Author:Holmes, AK (Miss Angela Holmes)
UTAS Author:Seger, A (Mr Andreas Seger)
ID Code:135026
Year Published:2019
Deposited By:Ecology and Biodiversity
Deposited On:2019-09-23
Last Modified:2020-01-07
Downloads:0

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