My first fishing experience in New Zealand came during two visits in the 1970s before moving here permanently in 1980. I have extensive diaries from the end of 1980 to the present day.
Anglers often talk about the good old days and it generally goes along the lines of ‘‘the fishing is not as good as it used to be’’. This is probably true and has probably been true since anglers started to fish. But how true is it? I picked out three of my diaries covering the seasons 2011-13 and looked at the entries pertaining to two rivers that I fish a lot, the lower reaches of the Mataura and the Maniototo stretch of the Taieri. I compared these entries with those of the current and the two previous seasons.
Was there much difference? Yes, two major differences, these being the number of fish caught and seen and the number of aquatic insects. Trout seemed to be fewer in number and mayflies in particular have been much scarcer in recent seasons. Most insects are scarcer now, including water boatmen, damselflies and sedges.
The drop in trout numbers could be related to scarcity of insects. Small trout feed on small insects, especially mayflies, and if they do not have enough, fewer trout will survive to adulthood.
So why have mayfly numbers diminished? There are probably two main reasons, one being that mayflies are cold-water creatures and do not do well in the higher water temperatures that we have experienced in recent seasons. The second reason is the widespread use of pesticides as they are euphemistically called. They are insecticides and do not differentiate between useful insects and pest species and kill them all (hence the decline of bees as well).
There is not much we (the human race) can do about water temperatures in the short term but we can use less insecticide if there is a will to do so. The streams that rise in the less developed hill country support good insect populations but further downstream they are greatly reduced or disappear altogether.
Anyway what about the fishing this weekend?
The heavy rain midweek has not affected rivers too much and those away from the east coast not at all. The water temperature has generally dropped from the high to low teens, which will keep the mayflies happy. The lower temperatures should stimulate the trout to feed to put on condition for spawning, which is getting closer.
The Clutha is still very low, which is why the gravel banks are so obvious around Balclutha at the moment and there is easier access to the water for anglers. Evening sedge rises are probably the best chance of a fish for fly fishers and soft baits for thread-liners, warm calm evenings being the best.
