This dataset was created for ZINB GAMM with (Harmful Algal Blooms) HABs weekly mean and wekly mean dataset from hindcast model.This 20 year dataset contains data on weekly mean cell abundance of harmful taxa, namely, Dinophysis acuta, Dinophysis acuminata, total Dinophysis spp., “Pseudo-nitzschia delicatissima” complex, “Pseudo-nitzschia seriata” complex, total Pseudo-nitzschia spp., Karenia mikimotoi and total Karenia spp. and environmental data, Sea Surface Temperature, Near Bottom Temperature, Sea Surface Salinity, Near Bottom Salinity, Mixed Layer Depth and Potential Envergy Defecit in the period from 1st January 1997 to 31st December 2016; this time period matches the hindcast numerical model output (20 year hindcast [1997-2016], SW_IRL_ROMS_Hindcast). This dataset was created for the use in statistical analyses to facilitate investigation into the habitat suitability of harmful algal species.