Temperatures close to lethal for trout

THIS week the temperature on the lower Taieri exceeded 24degC — this is getting close to lethal for trout. Presumably, some smaller lowcountry streams will have been warmer than the Taieri as they warm up faster during the day, and I would not be surprised if there were fish killed.

Although streams warm up, they do not do so evenly throughout their length, even over a short distance. Shaded areas heat up more slowly and the deeper pools will be the coolest close to the riverbed.

The last sentence gives a clue where you should fish if you are keen to brave the heat on the riverbank. The other choice is to fish faster shallow ripples, where trout lie to get a better supply of oxygen.

Fly fishers do not generally like to fish slow deep pools unless trout can be seen rising at the surface.

Fish can be caught when they are deep with weighted nymph, retrieved slowly if there is little current or just left to drift if there is enough current. I have often fished deep pools on the

Mataura this way and it is usually productive, but it takes persistence.

Of course, this is the time of year when anglers flock to the tussock lakes to catch trout gorging on cicadas. I’ve heard of fish being caught, and of blank days. It is almost impossible to guarantee catching fish even at the best of times. But when the cicadas are dropping on the water they can produce the best days of the season.

If you live in Dunedin it is hard to predict what the weather will be like up on the tussock. The temperature needs to be 18degC20degC for cicadas to fly and it will need to be much warmer than that at sea level — so really warm days will be the best.

Plan to be on the water before the cicadas fly off early and you can cast to trout at the start of the rise before they gorge themselves and go down for a nap.

I was running a fishing course on the Mataura at the weekend and it was pleasing to see a great fall of spinners at dusk on Saturday evening. It brought trout to the surface and gulls from miles around to feast on these dying mayflies. Unfortunately, when I cast my fly on the water it was surrounded by dozens of naturals and, as they ignored many of these real flies, my imitation was not given priority.

Four of us caught eight trout between us, hardly covering ourselves in glory.

The next day on the water with the class there was another fall of spinners and plenty of trout rising. It is really difficult to teach someone to cast when there are trout rising all around. In the afternoon trout were spotted in the ripples and they took a nymph which helped ease the pain of being ignored in the morning.