Spatial distribution of the nutrient plume emanating from an Integrated Multi-Trophic Aquaculture (IMTA) farm in British Columbia: use of an in-situ kelp bioassay to monitor nutrient loading.




Prussin, Emrys Adain

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To assess the spatial distribution of nutrient wastes around an open-water integrated fish/mollusk/kelp farm in-situ kelp bioassays were employed. Growth rates were measured over a four-month growing season and used as a proxy for relative nutrient concentrations. Seasonality and depth effects on growth rate were also assessed. Growth around the pens was 0.20 cm • day-1 higher than at the control, and reached a maximum of 1.4 cm • day-1. Optimal growth was achieved at 8 m. Growth at 8 m was significantly higher by 1.5 cm • day-1 compared to surface waters at 2 m. Early spring had the highest growth rates with a peak of 1.4 cm • day-1 recorded on June 21. This study re-iterates the fundamental benefits of IMTA and shows the potential of in-situ assay as an alternative to error-prone and costly water sampling to asses nutrient status in water.



IMTA, Integrated Multi-Trophic Aquaculture, Laminaria saccharina, Saccharina latissima, Bioremediation, Biomonitoring, Eutrophication, Kelp, Aquaculture, Sable Fish, Mussels, Scallops, Sea Cucumber