The Conservation Department is to implant radio tags surgically in trout in the Tongariro River to track their progress upstream.
Fishery technical support programme manager Glenn Maclean said 15 adult rainbow trout were fitted with radio tags at the Tongariro Delta last week and a third had been located around the
State Highway 1 bridge some 10km upstream.
In total, 65 trout will be implanted with radio tags at the Tongariro Delta over the next two months, along with 35 more above the Fence Pool.
The radio tags will allow the trouts' migration to their spawning grounds upstream to be followed.
Mr Maclean said the main purpose of the project was to determine what proportion of Tongariro trout used a small side tributary, the Waipa Stream, for spawning.
To protect the Taupo fishery, which is completely wild, scientists needed to have an accurate estimate of the number of trout swimming upstream to spawn.
"By knowing how many fish use the Waipa Stream and what proportion they comprise of fish entering the Tongariro we can estimate how many trout run up the Tongariro River each year," he said.
The information will be used when setting fishing regulations to ensure the fishery is not over-harvested.
The Tongariro has been chosen for the radio-tagging project because it is the most important breeding tributary of Lake Taupo.
Anglers catch around 20,000 trout there over the winter spawning period.
Anglers catching tagged fish should return the tag to DOC in Turangi with details of where and when the fish was caught.
- DAILY POST (ROTORUA)
