Tasmanian recreational fishers have contributed to an Institute for Marine and Antarctic Studies (IMAS) study of the potential ecological impacts of a salmon escape event in May 2018, when severe storms damaged salmon farming infrastructure off the east coast of Bruny Island.
Led by Associate Professor Jeremy Lyle, the IMAS study released today drew on the experiences of recreational fishers to examine the dynamics of dispersal, survival and possible impacts of the 120,000 escaped Atlantic salmon.
“More than 120 recreational fishers provided information about the locations, dates and numbers of Atlantic salmon caught,” Associate Professor Lyle said. “This information was used to map the dispersal of escapees from the farm site over time.
“The escape event attracted significant interest from recreational fishers, and while dispersal was rapid it appeared to be largely restricted to south-eastern Tasmania and to within the general Storm Bay region, including associated bays and tributaries.
“Recreational fishers were primarily motivated to fish for the escapees to take advantage of the windfall event and catch this premium table fish.
“Some fishers also expressed concern about possible ecological impacts, seeing an opportunity to help remove or fish-down the introduced species.
“Although catches declined quite quickly due to the combined effects of fishing and predation, some fish appeared to have survived at liberty for almost four months – although they were not thriving. In fact, there was only limited feeding by the escapees on native fauna.
“This is consistent with previous studies where farmed salmon seem to be poorly adapted to feeding on natural prey items.”
Associate Professor Lyle said developing a research response to these rare and unpredictable large-scale escape events was challenging.
“But the willingness of so many fishers to provide details of their catches meant that we’re now in a better position to understand the impact of these events,” he said.