What are marine pests?
Marine pests are highly invasive, non-native animals and plants that can cause significant harm to Victoria’s marine environment. These pests can include a wide range of salt and freshwater organisms from microscopic algae to various species of seastars, seaweed, fish, barnacles, sea squirts, mussels and crabs.
Marine pests can arrive into Victoria from other parts of the world or even other Australian waters. Many of these invaders can arrive accidentally through the aquarium trade or as unwanted tourists attached to the hulls of ships that visit our ports, or as larvae in ballast water.
Once introduced, marine pests reproduce quickly, often producing large numbers of offspring that can rapidly spread to new areas.
They compete with native species by preying upon them, and outcompeting them for space, light, food, or overgrowing them. They can also introduce diseases and parasites to our native species, and clog internal pipework resulting in overheating and damage to boat motors.
Australia has over 400 introduced and cryptogenic (unknown origin) marine species, including plants, animals and algae. In Victoria, Port Phillip Bay has at least 99 confirmed records of introduced and 61 cryptogenic marine pests, although some estimates put the number at more than 300.
Due to their invasive nature, marine pests pose a significant threat to our marine biodiversity and economy. Once marine pests become established, it is nearly impossible to eradicate them. Everyone can play a part in reducing the introduction and spread of marine pests. This section helps you know what marine pests to look for when visiting Victoria’s beaches and bays.