AUTHOR=Abdulhussain Ali H. , Cook Kathryn B. , Turner Andrew D. , Lewis Adam M. , Bibby Thomas S. , Mayor Daniel J. 

TITLE=The Influence of the Toxin-Producing Dinoflagellate, Alexandrium catenella (1119/27), on the Survival and Reproduction of the Marine Copepod, Acartia tonsa, During Prolonged Exposure

JOURNAL=Frontiers in Marine Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.652225

DOI=10.3389/fmars.2021.652225

ISSN=2296-7745

ABSTRACT=<p>Copepods can feed on, and may regulate, the blooms of harmful algae (HA), and may also facilitate dinoflagellate blooms by inducing toxin production and through selective grazing. However, exposure to HA may also cause mortality and reproductive impairment in copepods, with detrimental effects at the population-scale. Here we present the toxin profile of the dinoflagellate, <italic>Alexandrium catenella</italic> (formerly <italic>Alexandrium tamarense</italic>), and examine how it affects the survival and reproduction of the cosmopolitan marine copepod, <italic>Acartia tonsa</italic>. Healthy adult copepods were exposed to mono-specific diets of toxic and non-toxic strains of <italic>A. catenella</italic> (1119/27 and 1119/19, respectively) and non-toxic <italic>Rhodomonas</italic> sp. for 10 days alongside unfed controls to examine how their survival was influenced by likely HA bloom conditions. Additional 2-day experiments examined how their egg production rate and hatching success were affected by food deprivation, toxic <italic>A. catenella</italic>, a non-toxic alternative and a mixture of toxic and non-toxic prey, at high and low concentrations. Survival of <italic>A. tonsa</italic> declined over the 10-day experiment in all treatments but was not significantly lower in the toxic <italic>A. catenella</italic> treatment; mortality was only significantly enhanced in the unfed animals, which showed 100% mortality after 9 days. Egg production rates and hatching success from females in the unfed and toxic <italic>A. catenella</italic> treatments were all significantly lower than values observed in females fed <italic>Rhodomonas</italic> sp. or non-toxic <italic>A. catenella</italic>. Animals offered 1,000 μg C L<sup>–1</sup> of <italic>Rhodomonas</italic> sp. and a 50:50 mixture of toxic <italic>A. catenella</italic> and <italic>Rhodomonas</italic> sp. produced significantly more eggs than animals fed toxic <italic>A. catenella</italic> alone. These results were not apparent at prey concentrations of 100 μg C L<sup>–1</sup>. The percentages of eggs to successfully hatch from females offered mono-specific diets of toxic <italic>A. catenella</italic> were always close to zero. Collectively, our results indicate that adult female <italic>A. tonsa</italic> can acquire sufficient energy from toxic <italic>A. catenella</italic> to survive, but suffer reproductive impairment when feeding on this prey alone.</p>