European shore crab (Carcinus maenus) at Marino Rocks - Dan Monceaux 2015European shore crab (Carcinus maenus) at Marino Rocks - Dan Monceaux 2015

Since first learning about marine biosecurity and the translocation of marine species from one region’s waters to another via commercial shipping and recreational boating, I’ve come to recognise a few of our locally found invasive species. This summer I’ve added another invasive species to the list of alien organisms I’ve found while rock-pooling, beach walking or snorkeling along SA’s coast.

The most conspicuous invasive to be found in SA (in my experience) is the European fan worm. Not one to keep a low profile (quite literally) it juts out from jetty piles, and footings on wharfs, rocky marina walls and breakwaters.Being well adapted to life in marinas is a great strategy for the animals, as their offspring can then be transported attached to fouled boat hulls, or as larvae in the ballast water of larger vessels.


European fan worms at Semaphore jetty

(Taken by Steve Reynolds)

When feeding, the European fan worm casts a wide net while the organism’s long stalk-like body is able to sway with the current and broaden its reach even further. The animal combs the water for plankton snacks, and makes a decent living at it. Meanwhile, native species may struggle to compete for footings on jetty piles and for available food.

While the European fan worm Sabella spallanzani is easy enough to spot, even from above the water, invasive crustaceans or seastars can take a little more effort to detect. The other night, while walking with a flashlight south of the boat ramp at Marino Rocks, I found a European shore crab (also known as a European green crab). I wasn’t absolutely certain of the ID as I hadn’t encountered a live one before, but it didn’t resemble any of the usual crustaceans would otherwise expect to find in that environment.

The European shore crab is a known pest in Australian waters, so alerting relevant authorities to its whereabouts when sighted is critical. In South Australia we have a nice simple way for observers to share their sightings, thanks to the Conservation Council of South Australia and Reef Watch’s Feral or in peril website.

After your sighting is lodged, relevant authorities are notified and any data you provide (including photographs) is passed on.

At the moment, citizen science submitted accounts of invasive species in South Australia remain few, despite there being many known areas of local abundance. Peering into the water at the Glenelg marina or under suburban Adelaide jetties for example will practically guarantee you a sighting of the European fan worm. You’ll find them in both Spencer and St Vincent gulfs. The Wirrina Cove marina is also a haven for the worms too, which can easily hitch a ride on a vessel travelling from Wirrina to Kangaroo Island where invasive species are either absent or not noticeably established.

On consulting photographs from the rocky intertidal zone at nearby Kingston Park, I found that I had unknowingly captured more images of young European shore crabs. It would be of great benefit to the scientific and marine conservation communities to keep track of distribution and abundance of these species. I hope that these photographs will help give others the confidence to report sightings and report them.

PIRSA published a brochure on invasive species of concern in South Australia back in 2007, which is still relevant. The only change worth noting is that according to Reefwatch records, the North Pacific Sea, known for its infamous infestations in Tasmania and Victoria has been sighted in South Australian waters since publication. You can download the brochure at the link below.

Download PIRSA Introduced maricne pests of concern brochure, 2007
Download PIRSA ‘Introduced marine pests of concern’ brochure, 2007

(Reef Watch produced a Feral or In Peril underwater slate which features both the European fan worm and the European shore crab. We have two folders in our Society library, as part of the SDF collection, regarding invasive marine species. These are “A Guide to the Introduced Marine Species in Australian Waters (CRIMP), Tech. Rep. No.5, 1996” and “Marine Pest ID Cards” produced by the NSW DPI, 2004.))

As of 2015, PIRSA’s official list of ‘Marine Pest’ species appears below:

‘Marine Pest’ Species Common Name
Eriocheir spp. Chinese Mitten Crab
Hemigrapsus sanguineus Japanese/Asian Shore Crab
Crepidula fornicata American Slipper Limpet
Mytilopsis sallei Black Striped Mussel
Perna viridis Asian Green Mussel
Perna perna Brown Mussel
Corbula (Potamocorbula) amurensis Asian Clam, Brackish-Water Corbula
Rapana venosa (syn Rapana thomasiana) Rapa Whelk
Mnemiopsis leidyi Comb Jelly
Caulerpa taxifolia Green Macroalga
Didemnum spp. (exotic strains only) Colonial Sea Squirt
Sargassum muticum Asian Seaweed
Neogobius melanostomus Round Goby
Marenzelleria spp Red Gilled Mudworm
Balanus improvisus Barnacle
Siganus fuscescens Marbled Spinefoot, Rabbit Fish
Mya arenaria Soft Shell Clam
Ensis directus Jack-Knife Clam
Hemigrapsus takanoi/penicillatus Pacific Crab
Charybdis japonica Lady Crab
Asterias amurensis Northern Pacific Seastar
Carcinus maenas European Green Crab
Corbula (varicorbula) gibba European Clam
Arcuatula senhousia Asian Bag Mussel, Asian Date Mussel
Sabella spallanzanii European Fan Worm
Undaria pinnatifida Japanese Seaweed, Apron-ribbon vegetable
Codium fragile spp. tomentosoides Green Macroalga
Grateloupia turuturu Red Macroalga
Maoricolpus roseus New Zealand Screwshell

By Dan Monceaux

Dan Monceaux is a documentary filmmaker with a keen interest in marine biodoversity and conservation issues. He joined MLSSA in 2013 and served as Secretary from April-December 2014. Dan snorkels and has burning passions for underwater photography and citizen science.

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