Data for: A generalised volumetric method to estimate the biomass of photographically surveyed benthic megafauna

Standing stocks of biomass and biovolume as directly and indirectly estimated from photographs using a length-weight relationship (LWR) approach and a generalised volumetric method (GVM). The datasets correspond to: - the fresh trawl-caught specimens from the Porcupine Abyssal Plain Sustained Observatory (PAP-SO; 4850m water depth, northeast Atlantic); - the case study of benthic ecology based on a large photographic dataset derived from AUV surveys on the Celtic Shelf (100 m water depth, northeast Atlantic); - the inter-operator variation assessment of biomass and biovolume estimation using the LWR method and the GVM.