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Any benefits from allowing commercial trout farming would be "heavily outweighed" by the risks to New Zealand's wild trout fishery, Otago Fish and Game chief executive, Niall Watson, says.
His comments follow a Federated Farmers call for the prohibition on the commercial farming of trout to be lifted, in its submission to the Government's review of aquaculture law reforms.
Federated Farmers president Don Nicolson said lifting the ban would create a new business opportunity for the country.
In Norway, trout farming was worth half a billion dollars annually to that country.
"The annual European Union harvest of farmed trout is 203,000 tonnes, which is just under half [the weight of] of our lamb exports," he said.
Fly-fishing in Scotland seemed completely unaffected by Loch Etive sea-run trout sold in British supermarkets, he said in a statement.
"Strategically, aquaculture has major economic potential for New Zealand that needs to be harnessed in order to grow our economy."
Mr Watson said the prohibition on trout farming in New Zealand was appropriate and Otago Fish and Game would be supporting a continuation in that policy.
Calls for allowing trout farming failed in the past because of the importance of the country's wild trout fishery as a tourism drawcard and the popularity of trout fishing.
"Most people consider the benefits from allowing trout farming are heavily outweighed by the risks."
Risks came from the commercialisation of what was a non-commercial fish species and would encourage trout poaching in vulnerable spawning streams of the Central North Island lakes.
"Commercial-scale poaching would be a very serious risk in that area as well as elsewhere in the country.
Monitoring and enforcement costs would be considerable and successful protection of wild fish stocks would be difficult."
A proliferation of fish farm operations could mean a much greater risk of disease transfer, he said.
"That carries risks for trout hatcheries used for stocking recreational fisheries and for the relatively dispersed salmon farming operations currently operating in New Zealand, as well as having implications for wild trout stocks."
The only consents for commercial aquaculture granted by the Otago Regional Council since 2004 were for taking seawater for shellfish storage.