1383. Hon Alison Xamon to the Minister for Environment:

I refer to the resident population of bottlenose dolphins in the Swan Canning River system, and a March 2017 study by the Environmental Protection Authority (EPA) in South Australia titled Per and polyfluorinated alkyl substances (PFAS) in the marine environment, and I ask:

(a)  what is the estimated total resident dolphin population in the Swan–Canning Riverpark, including by item:

(i)  breeding mothers;

(ii)  males;

(iii)  youngsters; and

(iv)  others;

(b)  is the Government aware of any further research being conducted into the effects of PFAs on the Swan–Canning River dolphins, since the South Australian EPA’s report was released:

(i) if yes to (b), will the Minister give details;

(c) does the Government consider health effects from toxic contaminants, poor water quality from nutrient contamination and toxic algal blooms among the top five threats to Swan River dolphins, along with entanglement in discarded fishing line and loss of habitat and decline in food species; and

(d) if no to (c), why not?

Hon Stephen Dawson replied:

(a)  The Swan Canning Riverpark is home to 23 resident dolphins (excluding calves) which are a sub-population of indo-pacific bottlenose dolphins that frequent the coastal and estuarine waters, near Perth. Based on 2017–18 survey results, the resident group includes:

(i)  9 adult females;

(ii)  7 adult males;

(iii)  7 juveniles; and

(iv)  5 calves.

(b)  Yes.

(i) Ongoing research by Murdoch University is examining the health of coastal dolphin populations, including those in the Swan Canning Riverpark. This research is investigating biomarkers of stress and immunosuppression that may be indicative of exposure to a range of contaminants, including Perfluoroalkyl and Polyfluoroalkyl substances (PFAS).

(c) The Swan Canning Riverpark dolphin sub-population is small and vulnerable to pressures associated with a habitat comprising an urban estuary and a major harbour that has high recreational use and a large agricultural catchment. The range of anthropogenic threats in this environment include, injury and mortality from fishing line entanglement, exposure to boat traffic, noise, and vessel strikes, as well as exposure to potential toxins in the water column and through food resources. To date, there is no evidence directly linking toxic contaminants, nutrient contamination or toxic algal blooms to the death of any dolphin in the Swan Canning Riverpark.

(d) Not applicable.


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