When we received a phone call about dead fish floating around Lake O about two weeks ago, we immediately asked for an opinion from our inmates. For those unfamiliar with Lake Otamangakau this is our trophy lake and a very highly regarded BIG trout factory.
During Jan-Feb-Mar cicada season we have a steady (aka “mature”) group of inmates who suffer a infectious association with Lake O. One has been visiting TRM (in the same unt) for over 40 years. Others have varying skills and experience and views but they all suffer from an addiction with Lake O. In the summer they convert TRM into a fishing camp. Wonderful for SWMBO (She Who Must Be Obeyed is only concerned about trifling stuff like occupancy at over 90% so far for February) but this is a fishing update with far more important concerns than TRM survival. This is serious stuff. Fishing!
Soon after we received an email from a well known Taupo fisho which read: Morning Ross, we are hearing of trout dead trout floating in the middle of lake O have doc was told. Have you heard anything. Regards… D
After “consulting” our in-house experts we replied: TRM advised: “Hi D.
I immediately checked with our inmates. Most have already left for Lake O but those who slept in tell me several dead trout have been floating around the “hole” at the end of the canal for the last week. They blame poor release by anglers taking too long. The overall results up there in the last few weeks have been excellent.”
- To which he replied: “Thanks mate – a couple from up here said that they counted 6 nice fish floating around in the middle of the lake on Sat. regards D.”
Then we received more phone calls with warnings that the lake temperature is now up around 23 degrees c close to the limit for trout at around 26. Compounding a very hot dry summer, this is largely due to the canal from Whakapapa being closed and the shallow lake has heated up to the point where the trout can no longer survive being caught and released. i.e. After a battle with anglers they no longer have the reserves of energy to recover.
Panic set in when we discovered the regular team from TRM had deserted Lake O for Lake Rotoaira and Kuratau. Most uncharacteristic for these Lake O disciples. That is really serious… Rumours continued to bounce around at beer time but who would really know how serious is this problem?
The other questions from anglers were what are the Fishery Managers – Department of Conservation – doing about it? They had been told last week. They have been out there recently cutting the new track from the toilet at the launching ramp across the swamp to the inlet canal. Anglers suggest they should have placed a notice up advising all trout caught have to be kept
Fishos have also suggested that the power company completing the pipe/canal maintenance should have timed it better during June when Lake O is closed for fishing and the temperatures would not be an issue? Or is there another reason?
Finally, thankfully, SWMBO’s Hero reported in – the only one prepared to get off his butt and investigate this further – no other than Didymo Dave of course. He writes on his facebook:
“DEAD FISH AT LAKE O………In the past couple of weeks anglers at Lake O have noticed dead trout on the surface of the Lake. As a result all sorts of theories have developed, most of which are BOLLOCKS! Checked with some fishery scientists today (Not DOC) to make sure my facts were right before posting this. There are currently 2 problems: 1) There is a flow meter on the Whanganui River around Taumarunui n when the flow in that river decreases to 24 cumecs Genesis Energy, under their resource consent are required to shut the western diversion down. We are at that stage so while there is a little bit of water coming out of the Whanganui intake, its really only the Te Whaiau n Papaki Streams that are flowing into the Lake. 2) At 26 degrees surface water temp, given Lake O is shallow some mortality of trout will begin to occur. Today it was 24 degrees which means the trout are struggling for oxygen, their metabolism is shutting down, they aren’t feeding much n they are under big pressure. So add the stress of being caught into the equation n even if handled with kid gloves some will die when released. Add into that poor catch n release technique, holding them up for photos n dead fish is, sadly, what we will have. So thanks to the 2 blokes who helped me understand what’s going on n if anyone has any questions speak up. Cheers.”
Thanks Dave