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Government of Western Australia - Department of Fisheries

Biosecurity alerts

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 five languages:

How to clean blue swimmer crabs video

Alexandrium FAQs

Alexandrium algal bloom information 

Alexandrium blooms monitoring

Blooming surprise Landscope article March 2021.pdfBlooming surprise Landscope article March 2021.pdf

Look out for caution signs installed at key Swan Canning Riverpark locations including jetties, traffic bridges, boat ramps and popular fishing locations.

Alexandrium warning sign.jpg

Biosecurity Alerts

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

Biosecurity fact sheets

Indistinct river shrimp

Asian green mussel

Last modified: 26/03/2021 2:15 PM

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