Trawl and ROV survey data supporting "Long-term decline and changing drivers of drift macroalgae in a nutrient-limited embayment"

This dataset contains field observations used to evaluate long-term changes in drift macroalgae and the environmental drivers of epibenthic community structure in Port Phillip Bay, Victoria, Australia. Standardised otter-trawl surveys conducted in 2017–2018 and 2021–2022 quantified the wet-weight biomass of major macroalgal groups at three locations and multiple depth strata. Remotely operated vehicle surveys conducted between February 2022 and August 2023 quantified mean semi-quantitative cover scores for macroalgae, seagrasses and selected epifauna across the north-western region of the bay. The ROV data include water depth, distance to the nearest Western Treatment Plant discharge drain and monthly depth-averaged nitrogen concentrations derived from the Bubbles hydrodynamic–biogeochemical ecosystem model. The data support analyses reported in the associated article, “Long-term decline and changing drivers of drift macroalgae in a nutrient-limited embayment.”