Tamar River lovers got a taste of the many scientific and historic facets the area has during Tamar Discovery Day at Seahorse World.
The biennial event featured a number of stakeholders in the river including NRM North, Petuna Aquaculture, Plastic Free Launceston, Fishcare Tasmania and the QVMAG.
Event coordinator and NRM North Tamar Estuary and Esk Rivers Program officer Dr Darcie Leong said the day was a chance to celebrate all the important aspects of the river.
“We’ve got a variety of stalls here that are showcasing some of the amazing things about the estuary, whether it’s recreational fishing to less nice things like marine debris,” she said.
“We’re highlighting some issues and how the community themselves can help protect the Tamar Estuary.”
Dr Leong said the day was all the more timely with World Rivers Day occurring next weekend.
“World Rivers Day is basically a chance to spotlight rivers around the world … it’s one of the biggest environmental organised days of the year,” she said.
Tamar Wetlands Volunteers president John Duggin was one of many stallholders highlighting pressing issues for the river.
He was showcasing an invasive species of fish named gambusia.
“It was released illegally in the late 1990s … eventually it escaped from a farm dam and got into the Tamar,” Mr Duggin said.
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Gambusia’s reach spans from Home Point to Windamere, with a hotspot at the Tamar Island Wetlands.
Mr Duggin said gambusia’s consumption of food sources posed a threat to local organisms including dragonflies and threatened species the green and gold frog.
“What we’re seeing now is a possible interruption of the food chain for all the other organisms,” he said.
“When we collected water samples years ago for kids, you’d always get lots of insects and invertebrates … now it’s difficult to find good samples and anecdotal evidence.”
To combat gambusia, a joint study conducted by UTAS and other groups is looking to sex reversal as a method of reducing the population.
“It starts off with a normal female which then gets fed testosterone which turns the female into a sex-reversed male,” Mr Duggin said.
“You breed it again with a female and continue to do so until only males are produced … you release those into the wild and they can only produce males … the idea is to cause the population to crash.”
Mr Duggin said the study required significant testing to avoid inadvertently aiding the gambusia population.
“The last thing we want to do is have a similar problem to cane toads,” he said.
Dr Leong said the variety in stalls made for an enigmatic day for adults and children looking to bolster their understanding of the Tamar.
“There is quite a diverse array, whether it’s science, history or community engagement in trying to spark their interest in the Tamar and getting them to think a bit more as well as understand the river and what they can do to help,” she said.
“As someone who loves science, being able to disseminate that information rather than just be on an academic paper … being able to share all this amazing science with people from various ages is crucial.
“That way, everyone gets to enjoy this information and they get to act on it … it all comes to down to everybody helping out together, doing these big cleanups and everyone being able to control what they catch so we’re … working together to protect the Tamar.”