37 7th Veterinary Report - Department of Primary Industries ...

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Contents Veterinary Investigations Executive Summary ………………………………………………………………………………………..3 Silver Perch Kill, Bass Deformity and Neurologic Syndromes …………………………………………………………………..6 Mullet Deformities Syndrome …………………………………………………………………………………………………………………9 Bass Fry Kill Syndrome ……………………………………………………………………………………………………………………………10 Golden Perch Loss Syndrome ………………………………………………………………………………………………………………….12 Australian Bass Growth Retardation Syndrome ……………………………………………………………………………………..14 Silver Perch Larval Malformation,Discoordination and Acute Death Syndrome ……………………………………..16 Supporting Documents ………………………………………………………………………………………………………………………….18 Literature ………………………………………………………………………………………………………………………………………………20 Acknowledgements ……………………………………………………………………………………………………………………………….26 Photos cover page : Upper 1 st row ‐left – Silver perch deaths associated with spraying activity. Upper 1 st row‐right – Australian Bass twin body deformity from Noosa broodfish – histology. Upper 2 nd row left – Mullet embryo with three tails from Noosa broodfish. Upper 2 nd row right – Noosa mullet broodfish which produced deformed progeny. Lower 1 st row left – Fish pond and macadamia trees. Lower 1 st row right – Australian bass fingerlings with retarded growth. Lower 2 nd row left – Australian Bass fry from non‐Noosa broodfish, no deformities. Lower 2 nd row right – Golden perch gills with hypertrophic pathology, associated with nonylphenol exposure. (Photos with are Copyright 2010 Gwen Gilson.) Report to Noosa Fish Health Investigation Task Force 7th Veterinary Report Executive Summary of Veterinary Investigations Page 2 of 27
Veterinary Investigations Executive Summary The Noosa Fish Health Investigation Task Force was a unique and timely opportunity to study and record the risks and effects of agrichemicals and pesticides on fish health. It was a complex investigation which utilised the strengths of veterinary science with its multidisciplines of epidemiology, pathology, parasitology and toxicology. As a result, a clearer understanding of the fish health syndromes was achieved in the past year. The interplay of the risk factors involved with agrichemical use and the responses of a highly sensitive group of animals – fish, has been methodically described as six major syndromes. This provides a practical foundation from which to harness and apply effective solutions. It will ensure that the health of the horticultural, aquacultural and ecological assets of the Noosa river catchment are sustainably protected into the future from inadvertant agrichemical contamination. Silver Perch Kill, Bass Deformity and Neurologic Syndromes Silver Perch Kill The epidemiological evidence was consistent with the silver perch being at high risk of acute exposure to very low sublethal but toxic doses of beta‐cyfluthrin pesticide. The pesticide, in combination with gill hyperplasia pathology caused by gill fluke parasites and moderate level background heavy metals was a significant additional stress to the fish. When high environmental temperatures occurred concurrent with pesticide spray days, the combined interplay of risk factors produced a major fish kill at the hatchery pond of silver perch. The fish were normal right up till the week of beta‐cyfluthrin spraying by the macadamia plantation. Australian Bass Deformity Pathology confirmed the two headed deformity in fish embryos reported and this appeared to indicate interferance with the control mechanisms of the embryonic cells. The implication would be reproductive failure of the bass population in the Noosa river as fewer young fish are produced or survive. Normal bass fry were produced by Sunland Hatchery when non‐Noosa broodstocks are used; which strongly points to the Noosa river as being the source of potential chemical toxins with mutagenic and genotoxic properties. Golden Perch Neurological Derangement A pathological lesion of spinal inflexion and fracture was consisitent with reports of partially atropine responsive treatment of spinning problems with fish larvae at Sunland Hatchery. This supports the real risk of exposure to organophosphate type pesticides. Spray log data confirmed that methidathion (an organophosphate) was used in the period associated with observation of spinning or convulsive symptoms in the fry particularly after water from ouside the hatchery building was used in spawning tanks. Mullet Deformities Syndrome (MDS) MDS pathology is very similar to the two headed bass syndrome because three tails or axial multiplication occurred. The serious implication is that a common agent is causing reproductive damage to more than one species of fish in the Noosa river. MDS was clinically presented as resulting in the failure of normal, full‐term development of fertilised mullet eggs. Carbendazim and atrazine agrichemicals were detected in the catchment at very low levels which appear to be innocuous, but is it ? given the epidemiological evidence of a potential common link. Bass Fry Kill Syndrome Evidence of liver and red blood cell pathology in affected fish pointed to potential methoxifenozide contamination of algal feeds held in uncovered tanks outside from spray drift of macadamia operations leading to acute deaths of hatched Australian Bass. Fish that were not fed the algae on the days of agrichemical spraying did not experience similar mortalities. Golden Perch Loss Syndrome Parasitology detected an external parasite Costia sp. protozoan as the main cause of low survival from 10,000 fry stocked in a pond. Interestingly, pathology also detected toxic injury to gill, liver and red blood cells not related to Costia sp.. Carbendazim, nonylphenol, trichlorphon/dichlorvos, 4‐t‐octylphenol, bisphenol A and urea agrichemical residues were detected from water storage locations on the Gilson Rd. hatchery. This was clear evidence of contamination from macadamia spray drift for carbendazim, nonylphenol and trichlorphon/dichlorvos. Australian Bass Growth Retardation Syndrome (ABGRS) Report to Noosa Fish Health Investigation Task Force 7th Veterinary Report Executive Summary of Veterinary Investigations Page 3 of 27
Page 1: Report to Noosa Fish Health Investi
Page 5 and 6: Develop effective tools for sensiti
Page 7 and 8: toxic level of beta‐cyfluthrin wh
Page 9 and 10: Mullet Deformities Syndrome Mullet
Page 11 and 12: B. As the hatchery is a commercial
Page 13 and 14: Summary Risk Assessment Statement T
Page 15 and 16: The recommendations of this report
Page 17 and 18: B. Nonylphenol, though not a pestic
Page 19 and 20: 14.12.09 10.2.2010 6.1.2010 09‐1
Page 21 and 22: Ferguson, H.W. (2006). Systemic Pat
Page 23 and 24: NRA (2002). Public Release Summary
Page 25 and 26: Weiss, S.J. (1989). Tissue destruct
Page 27: Troy Ziesemer Roger Arbuckle Gwen G

37 7th Veterinary Report - Department of Primary Industries ...

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