TNPA Statement on introduced trout in the Tasmanian Wilderness World Heritage Area

The Western Lakes trout fishing community has been a major source of support in the long campaign against the proposed helicopter-accessed commercial tourism development at Lake Malbena. Greg French, an author well known for his enthusiasm for trout fishing in the Western Lakes, has been one of the most prominent campaigners against the Malbena proposal. His recent book Wild Heart of Tasmania provides many insights into both the history of the Western Lakes (essentially, the Central Plateau west of Great Lake) and the Malbena campaign. This connection led to the TNPA agreeing to promote Wild Heart. A TNPA supporter has, quite reasonably, questioned why TNPA has promoted this book when the author has made a career out of promoting the fishing of this “pest species” within the Tasmanian Wilderness World Heritage Area (TWWHA). Our response follows.

Trout were first introduced into Tasmania from England in 1864 and are now widespread. They are an invasive species that has undoubtedly caused substantial ecological changes, including the extinction of some native fish species, in waters where they have become established. Trout populations are generally self-sustaining so they are, for all practical purposes, impossible to eradicate even if it was considered desirable to do so. As an example of the difficulty of controlling feral fish, it has taken the Inland Fisheries Service (IFS) an “intensive 28 year program” to “functionally eradicate” a relatively isolated population of carp in Lakes Crescent and Sorell. In contrast, it would be relatively easy to eliminate large feral mammals such as deer if sufficient resources are made available, and TNPA advocates this.

Stocking of waters within the TWWHA with trout by the IFS is limited to a few easily accessed, heavily fished waters in the Nineteen Lagoons region of the Central Plateau Conservation Area where there is a long history of trout fishing. Officially sanctioned introductions to trout-free waters ceased decades ago. Trout are already present in most waters accessible to them – invasion of remaining trout-free catchments is unlikely without human intervention.

Where trout have successfully established themselves the ecological damage has been done and cannot be undone – trout have become part of the aquatic ecosystem – whether we like it or not. The presence or absence of recreational fishing will not significantly change this. This makes the protection of the ecological integrity of the remaining trout-free waters in the TWWHA and elsewhere in Tasmania all the more important. It is generally agreed that the major threat to the trout-free status of these waters is illegal introductions by overzealous trout fishers.

The Tasmanian Wilderness World Heritage Area Biosecurity Strategy recognises this; it includes brown trout in its list of high-risk invasive animals and identifies the risk posed by illegal introductions as “very high”.

The TNPA does not endorse all the views expressed in Wild Heart but one that we strongly support is Greg’s clearly stated position that our remaining trout-free waters need to stay that way. This statement from one of Tasmania’s leading writers on trout fishing is far more likely to influence those contemplating illegal stocking than any advice from a conservation group or government agency.

1st September 2023

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