Department of Primary Industries and Regional Development (DPIRD) staff reported the incident when visiting Beaufort Inlet on 13 April 2020 to inspect the estuary ahead of the Inlet’s May opening to commercial fishing, which lasts until October.
About a dozen recently killed fish were found at Millers Point (tarwhine and sea mullet) and less than 10 recently killed fish at Paperbarks Road site on 13 April 2020.
DPIRD staff returned to the site on 15 April 2020 to collect water samples for analysis by DWER. On this occasion hundreds of freshly killed fish were observed at a private river bank property about 1km upstream of the Paperbark Road site.
The results from water samples indicate that hyper saline conditions were probably the cause of the dead tarwhine (silver bream) and sea mullet collected near Paperbarks. Phytoplankton analysis indicated no harmful species of algae were present in Beaufort Inlet.
Salinity levels remain very high, as there has been little rain since last sampling in mid-March.
DWER’s Senior Natural Resource Management Officer Karen McKeough said this is the first opportunity the department has had to test water samples from the nearby Paperbarks site, which has given a broader picture of the water quality in the Pallinup.
“The salinity level at Paperbarks was lower than in the main basin of the Inlet, so this site was acting as a refuge from the increasing salinity and temperature in the water in the main basin which has probably led to fish dying over the past few months, Ms Keough said.
“But as the period of no freshwater inflows into the inlet has continued, even these refuges have become inhabitable, hence the recent deaths of sea mullet and tarwhine.”
Contact with dead fish should be avoided and the Department of Health advises against eating or handling fish found in these circumstances. Fish kills should be reported to the FishWatch 24-hour hotline on 1800 815 507.
