Alexandrium health warning
In the past two years there have been two unprecedented blooms of toxic dinoflagellate algae, Alexandrium spp., in the Swan and Canning rivers.
Alexandrium algae produce paralytic shellfish toxins (PSTs) which can be concentrated by filter feeding shellfish. These toxins are known to affect a wide range of species and may bio accumulate, resulting in potential impacts on crabs, fish, birds and mammals.
Human consumption of shellfish containing high levels of PSTs can result in poisoning and may cause death. Freezing and normal cooking processes do not destroy these PSTs.
Please do not eat mussels and remove the head, guts (mustard) and gills from blue swimmer crabs caught by recreational fishers in the Swan and Canning rivers, before freezing, cooking or eating them. All crabs must still be landed and transported whole to your home (your principal place of residence) unless you plan to eat them immediately.
Please see below resources related to Alexandrium algal blooms.
How to clean blue swimmer crabs flyer, available in four languages:
How to clean blue swimmer crabs video
Alexandrium FAQs
Alexandrium algal bloom information
Alexandrium blooms monitoring
Look out for newcaution signs installed at key Swan Canning Riverpark locations including jetties, traffic bridges, boat ramps and popular fishing locations.

Current biosecurity alerts are listed below. Fishers are asked to look out for these pests and to report evidence of them to FishWatch.
Marine pest alerts
Asian green mussel
Asian paddle crab
Black-striped mussel
European green crab
Japanese kelp
Northern pacific seastar
Redclaw crayfish
Spangled perch
Disease alerts
White spot disease in prawns
Indistinct river shrimp
Asian green mussel