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A different vibe on the river ...
Sun 11th October, 2015
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A different vibe on the river the last few days.
Its been a long cold winter but as the school holidays draw to a close its finally beginning to warm up and from now on its all change.
The series of freshes we had earlier this year knocked the insect life around a bit but they've bounced back and repopulated the rocks and stones of the river bed.
Most of this week there have been mid-morning and late afternoon mayfly hatches. The morning hatches often didn't amount to much but the afternoon hatch was usually much better and went on long enough to get a few fish rising to duns discarding their shucks in the surface film.
I haven't been on the river later than 6.00pm but on a couple of occasions as I was making my way back to the truck I bumped into fishermen who were just heading out wearing headlamps.
The majority of anglers are still doing ok nymphing and I don't think I've spoken to anyone who hasn't been catching fish.
Although the main runs are over fish trickle through all year on the Tongariro and the next month or so will see fish numbers at their highest.
Rainbows that ran the river much earlier in the year are slowly making their way back to the lake. As they move back more fish are still moving up. This crossover of kelts and fresh run trout is probably a 60/40 split now but as the runs decrease this will gradually alter and most of the trout caught will be recovering or "resident" fish.
I usually leave it until November before I start targeting browns but I'm already hearing of one or two fresh browns being caught. I haven't come across any myself but it wouldn't surprise me.
  During the winter runs its vital to fish your nymphs deep and keep them there as long as possible.
But things change from now on.
As the weather warms up, insect activity will build along with the hatches. As we head further into Spring fish can already be caught right through the water column, especially during a hatch. Hatches can occur at any time on the Tongariro particularly during the day... you just never know when ... but I'll tell you who does know ... the birds.
Finches will suddenly appear perched on the rocks at the rivers edge. If I'm nymphing this is when I grab the other rod. This little guy in Judges which I assume is the same bird has a favorite rock that sticks out of the water in the run at the head of the pool. He's normally the first to arrive. I don't know what alerts him that mayfly are about to hatch. There doesn't appear to be any insects on the surface at the time, so the hatch hasn't even begun when he first turns up. It can be several minutes, sometimes longer before you notice anything floating past. Then the may fly duns begin to break free of the rivers grip and fly skywards their wings shimmering in the sunlight. This is what the birds have been waiting for and because mayfly hatches in New Zealand tend to be fairly "thin" affairs there's no "safety in numbers" and they're very easily picked off.
During the day the fish seem to prefer to mop up the emerging nymphs below the surface and in the right water this is where the dry and dropper set up comes into its own. 
When ever I use this method I like to use flies tied on curved hooks. Don't get me wrong, there is absolutely nothing wrong with straight hooks.
Its just another of my little quirks and in this situation I feel more confident fishing with them.
That's because I think nymphs and larvae that enter "the drift" or are making they're way to the surface are more likely to have a curved profile.
Have a look at this clip from Tightline Productions a video production company based in New Jersey and you'll see what I mean: aquatic insects video
I fish this method a lot and have done for the last twenty years, ten of them on the Tongariro. I don't think its a coincidence that the patterns that consistently catch are all tied on curved hooks.
Mercer's Little Brown Bug, Rainbow Warrior, Caddis pupa emerger, Cadillac's, Quasimodo's and the Z Wing Caddis. All of these by the way are available from Creel Tackle and personally guaranteed by Grantly to catch fish ... eventually.
A lot of anglers give up on the Tongariro during the summer months, its a shame because they don't know what they're missing.
Ooophs! better shut, its quite nice having a river to yourself now and again.
Most of the time I practice catch and release. Its not that I have any sort of moral stance on whether to kill trout or not, its more to do with the fact that I don't like the taste of them.
Where ever possible I usually unhook fish without handling them. And because I nearly always flatten the barb or fish barb-less hooks its a fairly quick process which is less stressful for the fish.
But there are times you have to take hold of them for whatever reason.
So have you ever noticed how slippery spawning males feel. Its something I've picked up on over the years, particularly at the start of the spawning season. Sometimes if I'm taking a photograph for someone they really struggle to hold them. And its all they can do to get enough grip to pick one up. This is made worse because they've done the right thing and wet their hands first before handling the fish. This helps prevent damaging the layer of protective mucous which is so important to their survival. For instance it helps ward off parasites because they can't attach to the trouts slimy skin. Some studies suggest it might even help the fish swim faster by reducing the effects of friction on the water molecules. And of course it covers lesions and scrapes to help stave off infection. All of these are essential if you're a trout but if you're also a male spawning trout they become even more important.
Males have a rough time during the spawning season. They'll cover several females so for the jacks its a never ending round of fights and squabbles with other males. You only have to look at some of the very sorry looking specimens you catch during the latter part of the spawning runs. So I began to wonder if male trout produced more slime prior to spawning to help them survive the tough times ahead. I didn't know ... but I knew a man who might. Many thanks to fishery scientist Michel Dedual for the following:
"Hi Mike
I haven’t noticed any change over time, however, I have observed that the skin slipperiness does change over the spawning but in the opposite direction. Early in the season fish that move through Waipa are generally more slimy than later in the year and also that spent fish are more rough to the touch as the skin loses its protective mucus layer. I don’t know exactly by which process but the sexual maturation, exposure to pathogens, water temperature, overall health, and stress can all have a bearing on this.
I know that the enumeration of mucus secreting cells in the epidermis is used as a measure of stress in fish. The slippery feel of the mucus is considered to be predominantly the result of gel-forming macromolecules called glycoproteins and that preparations of this can stimulate the rate of wound healing in animals and the healing of diabetic foot ulcers in humans!
The fish skin mucus acts as a natural, physical, biochemical, dynamic, and semi-permeable barrier that enables the exchange of nutrients, water, gases, odorants, hormones, and gametes. Concomitantly, mucus plays a critical role in the defence mechanism of the fishes. Skin mucus has evolved to have robust mechanisms that can trap and immobilize pathogens before they can contact epithelial surfaces. This occurs because in this mucus layer, particles, bacteria, or viruses are entrapped and removed from the mucus by the water current. Furthermore, mucus in most fishes is continuously secreted and replaced, which prevents the stable colonization of potential infectious microorganisms.
The production of mucus can be controlled by the chemistry of the water where the fish live and the thickness of the mucus layer is determined by the balance between the rate of secretion and rate of degradation and shedding. Exposure to toxic and irritating substances has been shown to stimulate mucus secretion, increasing the thickness of the mucus layer.
As you can see it would be very difficult to explain the exact reasons for a change in average mucus abundance from trout in Taupo without having a substantial sampling and monitoring regime. However, I will pass on your observation to the rest of the guys handling 1000’s of fish at the traps and ask them if they have noticed anything like you have.
Tight line and screaming reeeeels
Michel".
  Everyone's talking about mayfly hatches at the moment but there are also heaps of caddis larvae in the river. I keep forgetting to take a photograph when it happens but occasionally there are so many you'll hook one off the bottom when you're nymphing.
And don't worry if you keep missing take after lightning quick take ... you're not losing your touch ... the juvenile fish are also making their way back to Lake Taupo and the Tongariro will soon be full of them as they migrate downriver. No wonder the browns in the river are licking their lips.
The weather forecast is a bit confusing. The next ten days are supposed to be unsettled again with rain or showers most days. But the long range outlook is for a drier than normal October with predominantly westerly winds.
Do what I do ... look out the window.
Tight lines guys
Mike |
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