Algal Bloom

The Hon. N.J. CENTOFANTI (Leader of the Opposition) (14:33): I seek leave to make a brief explanation before asking a question of the Minister for Primary Industries on the topic of the harmful algal bloom.

Leave granted.

The Hon. N.J. CENTOFANTI: At a recent hearing of the Joint Committee on Harmful Algal Blooms, senior officials from PIRSA confirmed that the government authorised the transfer of oysters from Franklin Harbour, an area impacted by the harmful algal bloom, to Haslam, which, at that time, was not affected and is still not affected by algal bloom.

The decision, according to PIRSA, was made on the basis of independent risk assessment and analysis, which the department stated was thorough and based on advice from algal bloom experts and oyster aquaculture regulators. However, further evidence presented to the committee indicates that two separate independent risk assessments and an internal PIRSA risk assessment exist. One of the independent risk assessments was commissioned by the South Australian Oyster Growers Association on the transfer of oysters during the harmful algal bloom, which was then reviewed by PIRSA veterinary officers, and the third was commissioned later by PIRSA regarding the risk of brevetoxin exposure and translocation.

Questions now arise as to whether the minister approved or allowed the transfer before receiving the final PIRSA-commissioned risk assessment, which specifically examined the risk of brevetoxin exposure and translocation associated with the Karenia species. Given the high risk that brevetoxin poses to both aquaculture stock and human health, and the potential to further spread the harmful algal bloom along our coastline, my questions to the minister are:

1. Did the minister approve or authorise the transfer of oysters from Franklin Harbour to Haslam prior to receiving the PIRSA-commissioned independent brevetoxin risk assessment that specifically considered the presence and risk of brevetoxin translocation, and, if so, what scientific advice or evidence was that approval then based on?

2. Was the minister aware of the second PIRSA-commissioned independent report on the brevetoxin translocation risks when that transfer approval process was being finalised?

3. If the final PIRSA report had not yet been received by the minister when the transfer was approved, will the minister explain why this decision was made before all scientific assessments were complete?

The Hon. C.M. SCRIVEN (Minister for Primary Industries and Regional Development, Minister for Forest Industries) (14:36): I thank the honourable member for her question. The movement of oyster stock between harvest areas is critical to many oyster farming operations to maximise oyster growth, maintain stock quality, manage farm logistics and respond to market pressure, with specific harvest areas having environmental characteristics that support particular life stages of oyster development. Some producers have become specialised in growing a particular life stage of oyster and may sell or move oysters when they grow beyond that life stage.

The movement of oysters from a closed harvest area to another harvest area requires authorisation under the regulations. These relays have previously occurred for closures due to the presence of some harmful algae species above trigger levels, or high rainfall and E.coli, with a relay request process in place to facilitate these movements.

Predetermined criteria have been developed nationally to inform relay authorisations, and the SASQAP relay protocols ensure compliance with the Australian Shellfish Quality Assurance Program (ASQAP) Operations Manual, the ASQAP Export Standards 2004 and relevant state legislation. In anticipation of a need to facilitate the relay of shellfish from areas closed because of biotoxins, a review of national and state relay requirements was led by the Department of Agriculture, Fisheries and Forestry (DAFF) in consultation with state governments. That was undertaken during 2023, and South Australia updated its relay guidelines in September 2024 in response to the review.

In response to the current algal bloom, and to better understand the risk that oyster relays may play in spreading Karenia species to unaffected areas, the South Australian Oyster Growers Association (SAOGA) commissioned an independent risk assessment. PIRSA facilitated a workshop of algal bloom experts and oyster aquaculture regulators from the United States, New Zealand, Tasmania and New South Wales to help inform the SAOGA risk assessment.

SAOGA advised PIRSA a couple of months ago that although they had finalised their risk assessment and had undertaken extensive consultation to form a position on oyster relays, there was not a unanimous view within the industry. SAOGA requested at that time that the government manage the risks in relation to oyster relays without a position from SAOGA. To inform the management of oyster relay risk, PIRSA animal biosecurity completed a risk review drawing on the risk assessment already completed by SAOGA, and concluded that both the absolute risk of spread of the algal bloom via oyster relays, as well as the relative risk these relays may play in spreading the algal bloom compared to other means of bloom spread, are low.

PIRSA informed oyster producers who were in attendance at the annual SAOGA seminar on 17 October that PIRSA would assess oyster relay applications on a case-by-case basis, and that the relay applications needed to meet national criteria to ensure food safety standards were met. Following the SAOGA seminar, PIRSA received applications to relay Pacific oysters from Franklin Harbour, which is currently closed due to brevotoxins, to Haslam on the West Coast. I am advised there is only one oyster producer in Haslam. I am also advised that a subsequent email from SAOGA said that:

…owing to a unilateral view not being reached across the oyster sector at this time, we understand that decision making in relation to risk management of oyster movements must rest with the state government.

PIRSA had been advised by oyster producers that similar movements of large amounts of oysters were made from Franklin Harbour to Haslam in the three weeks leading up to the closure of Franklin Harbour on 30 July 2025, when at that time Karenia species counts were above 150,000 cells per litre, far higher than the Karenia detection levels at Franklin Harbour at the time of the relay request.

Importantly, weekly routine testing of Haslam has not detected an increase in Karenia species as a result of those movements. PIRSA assessed the relay applications against the criteria and risk assessment and the request to relay stock was authorised. The approved authorisations were time bound and to occur over a two-day period in October, which has now lapsed. The approval stipulated conditions requiring all relayed oysters to remain in a quarantined area separate to existing oysters for a period of 60 days and until brevotoxin levels met the strict food safety standards.

PIRSA will assess compliance with authorised relays through food safety audits scheduled for December 2025. PIRSA continues to monitor the presence of Karenia species and brevotoxin levels for impacted classified harvesting areas through the South Australian Shellfish Quality Assurance Program (SASQAP). I am aware several oyster producers and some fisheries, as well as others, have raised concerns of oyster relocation and possible potential to inadvertently spread the algal bloom.

In addition to the risk assessment, PIRSA has engaged regularly with the South Australian Oyster Growers Association over recent months. That is probably the main part of that answer, but obviously as more information comes in, we continue to assess that information and make decisions based on the information available.