Week 5: Information series for the State of the Marine and Coastal Environment 2021 Report

The Commissioner for Environmental Sustainability is exploring the themes from Victoria’s first State of the Marine and Coastal Environment 2021 Report, over nine weeks.

This week, we take a closer look at the Pests theme. Marine pests pose a significant risk to Victoria's marine environment and industries. They are highly invasive animals and plants that are not native to an area.

The report shines a light on the health of our marine and coastal environments to inform investment in marine and coastal science and management. It reinforces the need for a catchment to reefs approach to our policy and program interventions to protect and improve Victoria’s coastal and marine environments.

Did you know that there are more than 160 invasive marine species in Port Phillip Bay? The impacts of these invasive species are significant. For example, the northern Pacific seastar causes changes in fish populations. The population had reached 165 million just five years after the species was first detected. New invasive species continue to arrive, most recently the Asian shore crab in late 2020.

The report includes other findings related to marine pests, including:

  • Western Port has several known invasive marine species, although the size and number of infestations is significantly less than in Port Phillip Bay. 
  • Corner Inlet has remained relatively free of invasive marine species. Japanese kelp has been detected at Port Welshpool, and the northern Pacific seastar has been detected at Tidal River. 
  • The northern Pacific seastar was also detected in the Gippsland Lakes in 2015 and 2019. Fortunately, it was removed on both occasions.

Did you know that marine species are most commonly introduced and spread by ballast water and biofouling? Ballast water is taken on board by vessels to maintain stability and trim. It can contain thousands of aquatic microbes, plants and animals which can spread across the globe when released. Vessel biofouling happens when marine plants and animals grow on the submerged parts of a vessel or infrastructure. Read about what can be done to help prevent marine pests from hitching a ride.

More information