Date: 15 March 2012
There has been some debate about the Department of Conservation’s (DOC's) plan to investigate re-instating the winter runs of rainbow trout into the Tongariro River. The purpose of this statement is to clarify the facts about the trout fishery and the trial.
- As fishery managers DOC recognises the value of the brown trout fishery in the Tongariro River, and that it is worthy of protection as the world class angling opportunity that it represents.
- DOC does not have any intention to undertake culling, or any other sort of control, of the brown trout population.
- While brown trout do eat juvenile rainbow trout, and their offspring do provide competition for juvenile rainbows, they are only one of a number of possible reasons for declining numbers of early running rainbow trout in the Tongariro River.
- The Lake Taupo trout fishery is classed as a wild fishery as it is sustained by natural spawning and does not rely on hatchery releases or stocking to ensure sufficient numbers of trout for anglers or for reproduction in future years.
- For a number of different reasons, including environmental factors, the timing of the traditional winter spawning runs has become much later, with a spring run now being the norm.
As fishery managers, DOC wants to understand why the timing of the winter spawning run is changing and explore the feasibility of restoring early runs in the Tongariro system. The fishery at large will still rely upon natural spawning to ensure its future.
To do this DOC is embarking on a trial release of up to 20,000 juvenile rainbow trout into the Tongariro system in June 2012.
The fish will be from either Lake Otamangakau or Lake Tarawera, depending on the findings of a comprehensive genetic study, and will originate from early running adults, so will hopefully breed early (in 2-3 years time).
Upon release into the Tongariro system, the juvenile rainbows will be of a suitable size to avoid the likelihood of being predated upon by brown trout. They will also be tagged so they can be monitored to see if they return as early running adults.
The trial will run over three years, so the experiment will be refined, based on our results, to improve the outcomes of the trial.
In the meantime, anglers can enjoy some excellent fishing as the Tongariro River brown trout make their way upriver to spawn.
For more detail please read issue 64 of Target Taupo.