Northern Pacific Seastar Clean Up Drive

The Northern Pacific seastar was introduced to the Derwent estuary in 1986 via ballast water from Japan. The invasive seastar feeds on shellfish, crabs, ascidians, urchins and other seastars including each other. The northern Pacific seastar consumes invertebrates and sponges and in high densities can clean out an area of these rapidly. Their breeding success is optimal when present in high densities and when food is abundant. So, reducing the density of these invasive seastars may also result in lower breeding success.

The northern Pacific seastar can tolerate a wide salinity range (18-41ppt) and while in its native environment prefers water temperature of 7-10°C, has adapted to warmer temperatures in Australia of up to 22°C.They become mature when around 10cm in size. Spawning occurs between July and October in Australia. Each female is capable of carrying up to 20 million eggs. These invasive species can also regrow arms as long as a part of the central disc is intact. Making removal the only control option.

The volunteer clean-up program coordinated by Benita Vincent involves scuba divers, snorkelers and non-divers. The program aims to reduce the numbers of northern Pacific seastar from heavily infested areas and areas that are important to the endemic and endangered Spotted handfish.

The spotted handfish are unable to move far, they don’t swim. So, it is very important that areas they live in are biodiverse and include food and substrate they need to survive and reproduce.

Regular clean ups are conducted and currently the removal of more than 900kgs has been achieved. Information is maintained on the progression of the clean ups via the Facebook page “Invasive Starfish Clean Up, TASMANIA” and membership is over 500!

Adreno Scuba has kindly donated equipment for the clean ups including catch bags and dive flags. The Ocean Hunter bags are particularly good as they have a zip on the bottom making it really easy to empty the catch.