Threats to the Bays

Science & MonitoringUN SDGs & UN SEEA
Northern pacific sea star and fan worm

This week, as part of our 11-week campaign to celebrate Victoria’s marine environment, we wanted to look at threats to Port Phillip and Western Port Bays, sharing insights from the Victorian State of the Bays (SotB) 2016 report, the prelude to the Victorian SMCE 2021 report – currently in preparation by the Commissioner for Environmental Sustainability. Despite their proximity to the city of Melbourne, both bays generally demonstrate healthy systems. Specific threats linked to population growth include variations in recreational use and variations in litter, nutrients, sediment and pollutant loads to the bays (which may lead to algal bloom events after heavy rainfall events).

Video of Life on Victoria's Bays

The SotB 2016 report assesses a diverse range of threats to the Bays, including climate change impacts such as heavy rainfall that transports high loads of nutrients and pollutants to the bays in short time periods. SotB 2016 also reported on water chemistry, water temperature, wind and storm patterns that  contribute to a complex mix of potential climate change impacts. Marine pests are also a threat. More than 100 introduced marine species (plants and animals) have become established in Port Phillip Bay including the European fan worm, Japanese kelp and Northern Pacific sea star. These pests can compete with native species, alter habitat, reduce important fish stocks and potentially disrupt nitrogen cycling processes. In SotB 2016, we reported that in Port Phillip Bay, an introduced sea star (Asterias amurensis) was outcompeting some bottom-dwelling fish for food, causing the populations of those fish to decline. An important benefit of regular reporting is to revisit these issues and assess if management actions are improving environmental outcomes over time.

Japanese KelpEuropean fan worm

Discover more about our bays here.