Murdoch University’s Algae Innovation Hub. Credit: Pierre Gildenhuys

Toxic algal blooms are of increasing concern in Australia, with South Australia’s coastal waters feeling their impacts in the form of damaged marine environments and widespread fish deaths since early 2025.

But what happens when the crustaceans and fish that encounter the toxins end up on our plates?

Dr. Cherono Kwambai from Murdoch University’s Algae Innovation Hub has developed and validated an analytical method to detect the toxins in the most popular seafood crustacean and successfully trialed methods of reducing the toxin load. The results of this research will help to inform best practice for seafood storage and preparation, bloom treatment, and toxin detection—which are critical to both environmental and public health.

Dr. Kwambai’s research focused on the toxic bloom Alexandrium minutum, and she quickly realized its impact could be hazardous not just ecologically, but also for public health. Her work appears in two studies in the journal Toxins.

The blue swimmer crab is the most harvested edible crab species in Australia—with 500–800 tons harvested commercially per year, and around the same numbers recreationally. As toxins from the bloom make their way through underwater ecosystems, they enter the bodies of aquatic animals such as the blue swimmer crab. Historically, the toxin has been difficult to detect.

"I found that these toxins accumulate exclusively in the hepatopancreas, a vital organ found in anthropods and mollusks," Dr. Kwambai said.

Upon validating her method of detection, Dr. Kwambai trialed methods of both reducing the toxin upon harvesting, and the removal of toxic Alexandrium cells from water.

"I also examined the effects of cooking and freezing on toxin levels, discovering that freezing and thawing can significantly reduce concentrations," she noted.

Dr. Kwambai conducted small-scale controlled trials using a PAC-modified clay on the bloom, which achieved up to 100% removal within two hours at low concentrations. The efficiency of this modified clay in saline water slurry offers significant cost and operational benefits.

Dr. Kwambai said this combined with the clay’s minimal risk to organisms living along the floorline of underwater environments supported the case for larger-scale, in-situ testing. She added that this research gave her the chance to contribute practical solutions to real-world problems, stating, "I wanted to bridge the gap between academic knowledge and everyday application—turning science into action that safeguards ecosystems, supports sustainable fisheries."

The results of this work will help to refine future research focuses across WA.

Primary supervisor and head of the Algae Innovation Hub, Professor Navid Moheimani, said this study showed what could be achieved when research was focused on locally relevant environmental challenges.

"Strong collaboration with local government is essential," Professor Moheimani said. "It is key to implementing practical interventions and ensuring that innovative science leads to meaningful outcomes for our coastal ecosystems and industries."

More information: Cherono Sheilah Kwambai et al, Effectiveness of Kaolinite with and Without Polyaluminum Chloride (PAC) in Removing Toxic Alexandrium minutum, Toxins (2025). DOI: 10.3390/toxins17080395

Cherono Sheilah Kwambai et al, Toxic Alexandrium Treatment in Western Australia: Investigating the Efficacy of Modified Nano Clay, Toxins (2025). DOI: 10.3390/toxins17100495

Citation: Two studies enable a method of detecting algal bloom toxins in popular seafood crustacean (2025, December 9) retrieved 9 December 2025 from https://phys.org/news/2025-12-enable-method-algal-bloom-toxins.html

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