Fishing for Atlantic salmon following a major escape event: inferences about dispersal, survival and ecological impact

A major storm event in southern Tasmania during May 2018 resulted in substantial damage to salmonid farming infrastructure located off the east coast of Bruny Island and the escape of an estimated 120,000 Atlantic salmon. The escape attracted significant interest from recreational fishers as well as raising concerns about the potential ecological impacts of such a large loss of fish.

In order to better understand the dynamics of dispersal, survival and impacts of the escaped Atlantic salmon, an on-line survey of recreational fishers was implemented. Over 120 fishers participated in the survey. Dispersal from the farm site was rapid but appeared to be largely restricted to south-eastern Tasmania and within the general Storm Bay region, including associated embayments and tributaries. During the first 4-6 weeks there were a number of reports of escapees being schooled up in various locations throughout the region, often associated with areas of freshwater or tidal inflows or within rivers and creeks. In such situations they were readily captured by gillnet and line fishing methods.

Based on capture dates, and assuming that most if not all were from the May escape event, at least some Atlantic salmon had survived at liberty for almost four months. This does not necessarily mean that these fish were thriving, in fact there was only limited evidence to suggest active feeding on native fauna.

Most recreational fishers fishing for the escapees did so to take advantage of a windfall opportunity and/or to capture a premium table fish. A proportion of fishers did, however, express concerns about the ecological impacts of escapees and were motivated to contribute to the removal or fish down of the introduced species.