May 03 2012

Trout Barrier Weir

(from Kerry)

Koaro are one of our native Galaxid freshwater fish species, often called kokopu.
They are able climbers and are one the many whitebait species. They are heavily predated by trout and were once abundant in Lake Rotorua, now only surviving in smaller tributaries away from trout.
DOC are trying to protect a small breeding population in the tributary stream by excluding trout from part of the stream, hence the trout barrier weir. Now that the weir has been installed, DOC will attempt to catch all trout upstream of the weir by “electro-fishing”. E.g. wading the stream with an electric wand and zapping the water periodically which stuns all fish temporarily, they then net the trout and move them down below the weir. Trout cant climb up over the dam, but koaro can if they need to.

The distinctive feature is the dorsal fin,
right at the back near the tail,
and the tail is small and stunted

(From Herma)
Tuesday afternoon we were walking in Hamurana Springs with our grandson and spotted what looked like a small waterfall. Since Kerry’s explanation we know it’s the trout barrier weir. Just a coincidence I had my camera with me;-)