One of our fellow fish vets (from Future Fisheries Veterinary Consultancy) is batting for accountability and a more responsible use of agrichemicals since finding evidence to support their detrimental effects on neighbouring farmed fishes (golden perch, silver perch, mullet, bass and saratoga). The aforementioned fish farm had been in operation for 20 years without incident and 5 years ago, has become bordered on 3 sides by a Macadamia plantation. The evidence suggests that elevated mortality rates (up to 100%) and increased incidence of deformities (from <10% to >25%) are a consequence of air and water contamination from spray-drift during the use of common agrichemicals.
Positive residue tests indicating off-site movement of pesticides onto the fish hatchery, and into its ponds and tanks and throughout the local river system (Noosa River). This included detections of carbendazim, trichlorfon, nonylphenol, octylphenol, bisphenol A, methoxyfenozide and urea at the hatchery. In the NoosaRiver carbendazim, endosulfan sulphate, atrazine, metalochlor, galaxolide and TCPP were detected in passive samplers.
Temporal epidemiological association between many acute mortality events and reported spraying activity. Weather reports corresponding to the times of chemical application on the plantation favoured spray drift (low humidity and high temperatures).
The syndromes recorded include mortality of adult fish in ponds; mortality of larvae in ponds; mortality of larvae and fingerlings in tanks; malformation of embryos and larvae in tanks (including absence of eyes, body length shortening, axial duplication (two heads) and triplication (three tails); growth impediments in fingerlings; and neurological dysfunction in larvae.
Dr Landos from Future Fisheries Veterinary Consultancy remains very concerned that the observed embryonic and larval mortality and malformation syndromes at the fish hatchery, may be occurring in wild fish within the Noosa River and more widely in agricultural catchments of Australia. Urgent regulatory precautionary action and research attention to this matter must be a priority.
