Random forest classification to determine environmental drivers and forecast paralytic shellfish toxins in Southeast Alaska with high temporal resolution

•Concentrations of paralytic shellfish toxins (PSTs) regularly exceed FDA thresholds for consumption in Southeast Alaska.•PSTs in blue mussels were modelled on daily timescales using environmental data from publically available data streams.•Salinity, temperature, freshwater discharge and air temperature were key variables.•Out of sample hindcast accuracy was low, limiting the functionality of a real-time forecast.