Project number: 2016-049
Project Status:
Completed
Budget expenditure: $95,000.00
Principal Investigator: Sharon E. Hook
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 14 Jul 2016 - 28 Feb 2017
Contact:
FRDC

Need

It is possible that by drawing water supply from pesticide contaminated estuaries, prawn farmers are inadvertently lowering their larval survival rates or are depressing growth efficiency because the pesticide mixtures in these waterways are causing toxic effects. It is also possible that the survival and growth efficiency of post larval stages is depressed by stocking into ponds with either contaminated sediment or contaminated water. While levels of imidacloprid measured by DSITI in the freshwater sections of some Queensland rivers would be sufficient to cause harm in some crustaceans, we do not know what the pesticide concentrations at the farms themselves are, especially not for the entire suite of potential toxicants currently in use, nor do we know how sensitive prawn larvae are to exposure to modern use pesticides. Once this information is available, we can perform a risk assessment for the aquaculture industry.
The aquaculture industry need this information about the risks to their operations posed by pesticide exposure to be able to accurately assess whether or not modern use pesticides pose a risk to their hatchery and pond stocking operations.

Objectives

1. Perform a desktop study of the potential impacts of modern use insecticides on the rearing of larval prawns.
2. Determine whether environmentally relevant concentrations of pesticide (imidacloprid, bifenthrin, fipronil, and chlorpyrifos) affect the survival and feeding behaviour of prawn larvae.
3. Analyse the intake waters from selected farms for the concentrations of pesticides, including the selected insecticides, to determine whether the concentrations approach those that could be harmful.

Final report

Authors: Sharon E. Hook Hai Doan Debra Gonzago Dean Musson Jun Du Rai Kookana Melony Sellars and Anu Kumar
Final Report • 2017-06-01 • 1.20 MB
2016-049-DLD.pdf

Summary

The use patterns of pesticides in Australia has changed over the last decade, with the use of pyrethroid and neonicotinoid insecticides increasing. The limited water quality data that is available has measured increased concentrations of the neonicotinoid insecticide imidacloprid in particular. Prawn farms in Australia are predominantly located adjacent to estuaries in Queensland, which are impacted by multiple land uses upstream (e.g. sugarcane farming, banana farming, beef cattle farming and urbanisation).  Because of their small size and rapid growth requirements, we would hypothesise that larval prawns would be most susceptible to the impacts of these modern pesticides.

While there is little ecotoxicology data for marine species, early life stages, or Australian species, the information available from studies with crustaceans conducted elsewhere suggests that the concentrations measured in this and other studies may be sufficient to cause impacts on survival, either directly or via inhibition of feeding. However, given the uncertainties in a) the levels of insecticides in farm intake water; b) the impacts of insecticide exposure on prawn larvae; and c) how these compounds interact when they co-occur, we can not adequately predict the impacts of these changes in pesticide use on the survival of post larval phase prawns.

To address these uncertainties, a series of experiments were conducted to determine the sensitivity of post larval prawns to these insecticides. To assess the potential for risk, a series of experiments examined the impact of exposure of post-larval black tiger prawns (Penaeus monodon) to modern use insecticides, imidacloprid, bifenthin, and fipronil as well as the organophosphate insecticide chlorpyrifos for comparison. Impacts were measured as decreased survival and feeding inhibition. Post-larval phase prawns were most sensitive to fipronil, bifenthrin, chlorpyrifos, and imidacloprid, in that order. They were comparably sensitive to other crustaceans based on literature studies. Bifenthrin and imidacloprid exposure also reduced the ability of post-larval prawns to capture live prey.
To determine the environmental risk of exposure to these compounds, concentrations of a broad suite of pesticides was measured in prawn farm intake waters. At least some pesticides were measured in every sample. Most of the pesticides detected were measured below concentrations that would be expected to cause harm to prawn larvae, although some herbicides were at concentrations that exceed either ANZECC/ARMCANZ or GBRMPA trigger values, suggesting the possibility of indirect or mixture related impacts. However, in the Mackay Catchment and Logan River, imidacloprid, bifenthrin, fipronil and chlorpyrifos insecticides were measured at concentrations that pose risk to prawn larvae. The potential for interactive effects and the limitations of basing risk on water samples collected at a single time point are discussed.

Related research

Industry
Industry
Adoption
PROJECT NUMBER • 2022-133
PROJECT STATUS:
COMPLETED

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