By Michael Morrah
Conservationists are using sophisticated technology in the fight against illegal trout fishing.
Every year thousands of tourists travel to New Zealand and spend millions of dollars as they fish in our streams and lakes.
The poachers who put that industry at risk are now likely to end up on camera.
On the banks of a stream that flows into Rotorua's Lake Tarawera, a hidden camera is rolling.
Anthony Van Dorp, a fish and game compliance officer, watches as two men with large landing nets attempt to scoop trout out of the stream.
The stream is closed to protect spawning trout so any kind of fishing here is illegal.
At the Ohau Channel near Rotoiti, poachers are again at work catching fish with bait which is illegal.
It is footage like this which is helping conservationists prosecute poachers and it is being captured on a camera, they say is almost impossible to detect.
Mr Van Dorp showed us a stream where spawning trout are particularly vulnerable to poachers and then the equipment which is helping stop such behaviour.
Rotorua has the highest rate of poachers targeting spawning trout in the country. Last year 15 were caught. It may not sound like many but it is enough to wipe out an entire spawning population in a waterway.
The trout population is a sports fishery and it is worth millions of dollars to the local and national economies for people who come and fish.
Just last week while counting trout, fish and game officers came across another group of alleged poachers.
On top of the poachers there is another challenge.
Volcanic soil and ash in riverbeds can smother eggs, resulting in a poor survival rate. So hatcheries like the one at Ngongotaha Valley are crucial.
Poachers can be fined $10,000 or jailed for a maximum of one year - and to ensure a healthy population in the future, officers say they will continue using covert techniques.
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