Marine Protected Areas (MPAs) are vital for conserving biodiversity and managing fisheries, but their effectiveness requires regular assessment. This study evaluated the ecological impacts of a 20-year-old no-take MPA in Port Phillip Bay, Victoria, using Baited Remote Underwater Video Stations (BRUVS) inside and outside the MPA from 2018 to 2022. We assessed fish assemblages, key species, and habitat associations.
Fish assemblage structure differed between MPA and non-MPA sites. Although species richness, abundance, and evenness showed no significant differences, Generalized Additive Models (GAMs) detected an increase in abundance inside the MPA. Fisheries targets, bluethroat wrasse (Notolabrus tetricus) and six spine leatherjackets (Meuschenia freycineti) were more abundant inside the MPA. In contrast, sand flathead (Platycephalus bassensis) and snapper (Chrysophrys auratus), also targeted by fisheries, showed no response while fiddler rays (Trygonorrhina dumerilii) were more abundant outside the MPA. In general, reef-associated species benefited more from protection than those in soft sediment habitats.
These findings highlight species-specific responses to protection and emphasise the importance of habitat in MPA effectiveness, underscoring the need for targeted conservation strategies and continued temporal monitoring programmes.