Pesticides used in viticulture create a potential risk for the aquatic environment due to drift during application, runoff and soil leaching. The toxicity of sixteen pesticides and one metabolite were evaluated on the growth of two marine microalgae, Tisochrysis lutea and Skeletonema marinoi, in 96-h exposure assays conducted in microplates. For each substance, concentrations of stock solutions were analytically measured and abiotic assays were performed to evaluate the chemical stability of pesticides in microplates. For two chemicals, microalgae exposures were run simultaneously in microplates and culture flasks to compare EC 50 calculated from the two exposure systems. Results from chemical analyses demonstrated the low stability of hydrophobic pesticides (log K OW > 3). For such chemicals, EC 50 values calculated using measured pesticide concentrations were twofold lower than those first estimated using nominal concentrations. Photosystem II inhibitors were the most toxic herbicides, with EC 50 values below 10 μg L −1 for diuron and around double this for isoproturon. Chlorpyrifos-methyl was the only insecticide to significantly affect the growth of T. lutea, with an EC 50 around 400 μg L −1. All fungicides tested were significantly toxic to both species: strobilurins showed low overall toxicity, with EC 50 values around 400 μg L −1 , whereas quinoxyfen, and spiroxamine, showed high toxicity to both species, especially to T. lutea, with an EC 50 below 1 μg L −1 measured for spiroxamine in culture flasks. This study highlights the need to perform chemical analyses for reliable toxicity assessment and discusses the advantages and disadvantages of using microplates as a toxicity screening tool. 2 Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. Highlights ► The toxicity of 17 pesticides was tested on two microalgae species. ► A microplate assay was developed for accurate determination of EC 50 values. ► Analytical measurement of exposure concentrations was performed. ► Significant differences between nominal and measured concentrations were found. ► Four herbicides, one insecticide and four fungicides showed significant toxicity.

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Somatic growth is a critical biological trait for organismal, population, and ecosystem-level processes. Due to its direct link with energetic demands, growth also represents an important parameter to estimate energy and nutrient fluxes. For marine fishes, growth rate information is most frequently derived from sagittal otoliths, and most of the available data stems from studies on temperate species that are targeted by commercial fisheries. Although the analysis of otoliths is a powerful tool to estimate individual growth, the time-consuming nature of otolith processing is one barrier for collection of comprehensive datasets across multiple species. This is especially true for coral reef fishes, which are extremely diverse. Here, we provide back-calculated size-at-age estimates (including measures of uncertainty) based on sagittal otoliths from 710 individuals belonging to 45 coral reef fish species from French Polynesia. In addition, we provide Von Bertalanffy growth parameters which are useful to predict community level biomass production.