Alexandrium algal bloom caution
Following two consecutive years of significant Alexandrium algal blooms impacting the Swan and Canning Rivers, the Department of Primary Industries and Regional Development (DPIRD), Department of Biodiversity, Conservation and Attractions (DBCA) and the Department of Health (DoH) are adopting a proactive management approach prior to the opening of the blue swimmer crab season in the Swan and Canning rivers on 1 December 2020.
A new harmful algae caution sign has been installed at popular jetties, boat ramps and fishing locations around the Swan and Canning rivers. The sign advises recreational fishers not to eat mussels and to clean any blue swimmer crabs caught in the Swan and Canning rivers by removing the head, guts, mustard and gills prior to freezing, cooking and eating.
DPIRD and DBCA will run an ongoing Alexandrium education campaign and have created some Frequently Asked Questions, a brochure and a video to help inform recreational fishers and the general public of this public health issue. Alexandrium does not affect swimming and other aquatic activities in the rivers but you are advised not to swim in discoloured or smelly water.
What is Alexandrium?
Alexandrium is a group of microalgae that has been previously detected at elevated levels in the Swan and Canning rivers.
It has impacted waterways and fisheries around the globe, and is expected to be an annual occurrence in the Swan and Canning rivers.
These algae can produce Paralytic Shellfish Toxins (PSTs) that can impact mussels and crabs. At worst, poisoning by PSTs can be fatal to humans and there is no antidote, with treatment being supportive care and artificial respiration. A meal of 3-4 whole crabs can cause symptoms.
How can I reduce my risk?
To reduce your risk of ingesting PSTs:
• do not eat mussels from the Swan and Canning rivers
• clean any blue swimmer crabs caught in the Swan and Canning rivers by removing the head, guts, mustard and gills prior to freezing, cooking and eating
How can I find more information?
The Department of Biodiversity, Conservation and Attractions (DBCA) and the Department of Primary Industries and Regional Development (DPIRD) have developed an ongoing Alexandrium education program to alert the public and recreational fishers to the dangers of PSTs.
More information is available in the following publications available for download at the bottom of this page:
• 'How to clean blue swimmer crabs' brochure
• Frequently asked questions
• Alexandrium video
Look out for new 'harmful algae' caution signs that have been installed at key Swan Canning Riverpark locations including jetties, traffic bridges, boat ramps and popular fishing locations.
For further information on Alexandrium, please contact DoH on 9222 2000 or refer to the web pages provided on the DBCA and DPIRD websites.