Chilled-out fish: antidepressants in waterways impacts animal behaviour

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Monash University scientists are researching how fish are affected by pharmaceutical pollution. (Picture: Bob Wong Lab)

Medications excreted by humans are flushed into the sewerage network, with many bypassing wastewater treatment and flowing into rivers and bays.

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Behavioural Ecologist Bob Wong (Picture: Monash University)

Associate Professor Bob Wong, Deputy Head of the School of Biological Sciences at Monash University, leads a team of researchers investigating animal reproductive behaviour and the impacts of environmental change on behaviour and evolution.

Approximately 600 of 5000 commonly prescribed pharmaceuticals are found in waterways worldwide, Associate Professor Wong said.

“A lot of these medications end up in the environment and we know they can have profound impacts,” he said.

A recent publication by PhD student, Jake Martin, demonstrated a link in mosquitofish between lessened responses to predators and exposure to the widely-prescribed antidepressant fluoxetine, marketed as Prozac.

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When Mr Martin exposed fish to the drug at realistic pollutant levels, the animals were less likely to adjust their activity in the presence of a predator or after an unsuccessful predator strike.

“We’re saying that this is likely to make them more vulnerable to predation, whereby if they are missed by the first strike, they are more vulnerable and more likely to be detected for a second strike,” Mr Martin said.

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PhD student Jake Martin (Picture: David McAlpine)

Associate Professor Wong said researchers are only beginning to understand the impacts of pharmaceutical waste on evolution.

“By influencing reproductive behaviour, you can affect the number and the quality of offspring that are produced, which can then have important consequences for the health of populations and also the survival of species,” he said.

“At the moment, it’s not an issue which has captured enough attention. I don’t think it’s getting the attention from regulators as I think it deserves.”

“When we are potentially using wastewater to water our lawns, when we’re potentially talking about recycling water for human use, it does raise these kinds of alarming concerns about are we exposing ourselves unnecessarily to pharmaceutical pollutants and are we exposing our wildlife unnecessarily to pharmaceutical pollutants?”

The Wong group is now monitoring populations of fish exposed to fluoxetine over a longer period, to investigate the long-term effects of antidepressant exposure.

“I think that is really a key next step, which is to look at what are the longer terms impacts that exposure could have on wildlife,” Associate Professor Wong said.

“We want to see what impacts long-term exposure might have on these fish across multiple generations, so we’ll be looking at their behaviour, we’ll also be looking at various morphological traits, such as the colours of the males and various other things, to see what effects could occur across generations.”


Access to water is key to South Gippsland horticulture expansion, says grower

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Irrigation at Schreurs & Sons’ Tarwin Farm (Picture courtesy of @AdamSchreurs)

Increasing urbanisation is encroaching on traditional market garden areas on the fringes of Melbourne, with one grower expanding to new ground and an underutilised water supply in South Gippsland.

Schreurs & Sons is a third-generation family business based in Clyde, on the edge of Melbourne’s south-east suburbs, producing celery, leeks and baby leaf varieties of spinach, rocket and snow pea tendrils.

Dutch immigrant Joe Schreurs originally founded the farm at Dingley around 50 years ago and later relocated to Clyde to escape the wave of suburban development in the early 1970’s.

Now, the third generation of the family is facing a similar urbanisation dilemma to their forbears.

The older generation, who still owns the five Clyde properties, is selling the land for housing development as quickly as current business owners Adam, Ben and Chris Schreurs can find new land to relocate the business.

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From left: Chris, Ben and Adam Schreurs (Picture courtesy of Schreurs & Sons, @SchreursSons)

“Water’s what we look for first, that’s the hardest part to get. Water, then soil and climate, basically,” Adam Schreurs said.

With this in mind, the Schreurs purchased a 900-acre former dairy farm, over 100 kilometres away at Middle Tarwin in South Gippsland and have since converted around 160 acres of its fertile soil for celery production.

They had considered established irrigation districts such as East Gippsland but preferred the shorter distance from Middle Tarwin to their distribution facility at Clyde, Mr Schreurs said.

Mr Schreurs said they purchased water licences from farmers upstream on the Tarwin River, which enables them to pump water from the river into storage dams during the winter.

“We aim to be able to sustain ourselves out of the dam fully through the drier months of the year without drawing on the river, so we use about 3 megalitres per year per acre.”

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Harvesting celery (Picture courtesy of Schreurs & Sons, @SchreursSons)

Mr Schreurs said water allocation regulations currently prevent them from pumping extra water, beyond their normal allocation, from the river when it is in flood.

“If people are sensible about it we could pump the water when the river’s flooding, store it in dams and use it in the dry times,” he said.

A Southern Rural Water (SRW) spokesperson said that although major modernisation investments are focused on existing irrigation districts, they are monitoring the expansion of irrigated horticulture in South Gippsland and are planning to automate meter reading in the region.

“There may well be an opportunity for SRW to be more proactive in working with industry and individual growers in the planning for the expansion of water-intensive industries into areas that have historically been used for other purposes such as dairy or beef production.”

Water trading is a strong focus for SRW and we will continue to look for ways to improve access to water via trading rules and systems.”

In planning for future expansions, Mr Schreurs is also interested in alternative water sources, including desalinated water from the Victorian Desalination Plant or high quality recycled water from sewerage treatment facilities.

Southern Rural Water confirmed there are no plans to source water from the Victorian Desalination Plant for agricultural customers; however, they are “continually talking with other water sector agencies and industry bodies to investigate all viable options to improve water security for farmers across all of its regions”.