I was under such immense pressure from SWMBO in the laundry yesterday that I forgot which day it was and started TRM’s weekend Q&A’s one day early. SWMBO claims when you are happy in your work (?) time doesn’t matter.
TRM Fishing Guides reply to readers’ questions:
Question:
Hi, I am not sure if this is the correct address for Q&A but I love the concept.
I have been a long time reader of Taupo and Tongariro fishing report and have only recently come across yours after a reference in a competitors report! I can safely say that I will not be going back to the report in question after having read a few of yours!
My question is something I have been pondering for a while whilst pursuing fish in a range of rivers across the region. Do trout tend to spawn in the same river they originated from? I have often thought if a really low lake level will affect fishing on the smaller rivers or one off events will affect a river one season so that the maiden fish can’t come back next season. I know Salmon and eels tend to return to their place of ‘birth’, but is a trout spawned in the TT just as like to spawn again there, or head to the Tong or Waimarino?
Thanks very much!
James
Answer 1:
The rainbow trout in Lake Taupo are descendants of a steelhead strain introduced around 1898 and the original ova were imported from Sonoma Creek in California. Steelheads like salmon spend the vast majority of their life at sea returning to the rivers to spawn.Here in New Zealand these fish are land-locked so the lake has become their substitute ” ocean.” Once the eggs have hatched in the spawning streams the tiny fry quickly grow into small trout and after about a year eventually find themselves in Lake Taupo. For the next couple of years they feed up mainly on smelt and once they reach maturity their biological clock kicks in and they begin to gather at the tributaries waiting for suitable conditions to begin their irresistible upstream migration . They are pretty sensitive to their environment and as well as being able to detect things like fluctuations in barometric pressure can home in on the scent of the river or stream where they first hatched. These scents and smells entering the lake are one of the triggers that motivate them to begin this difficult journey.Tracking programs have discovered that once up river they will quite often swim some way past their place of birth but eventually drop back and find their natal stream…..I would assume because once past it that scent is no longer in that part of the river. Research shows that some of these fish may be imprinted to an area near the stream rather than the actual birth stream itself.
There is also evidence that they are able to recognize physical aspects of their place of birth.. providing it has not been altered by floods or changed in any other way. This is especially so if they are previous spawners and not maiden fish. After spawning unlike salmon not all rainbow trout die and around thirty percent survive…although by then they are pretty sorry looking specimens.If they make it back to the lake most of them will recover and be ready to do it all again the following year.
So just like their American cousins they will always endeavor to make their way back to at least the area where they first hatched.
Tight Lines
Mike
Answer 2:
This is a very interesting question which is sure to spark some disagreement but everyone has a view and thus is mine!!
It is a well known fact the Salmon and Eels around the world will always try and get back to the same river to spawn in which they were born. Trout are very similar species but the research into where a trout prefers to spawn remains a bit of a mystery to most. Trout will generally have several spawning years before the final run in which they die so if they did spawn in the same river you would think that this would have been documented and we would have a better understanding of the trouts re-producing habits. I would assume it would be a simple task of tagging a group of fish and seeing which trap on which river they turn up in the following year assuming they spawn every year and evade any disease,predators or anglers. In the past I know that Doc have tagged fish at the delta and watched how quickly they get up the river and graphed their progress per day etc so it should be a simple task.
I am a simple humble fisherman but over the years I have been fishing and guiding I certainly have noticed patterns regarding fish size in various rivers around Taupo. It is without a doubt that the Waitahanui and Hinemaia produce a much higher average weight than rivers like the Tauranga Taupo (“TT”) and Tongariro. In the same breath I believe the TT and Tongariro receive better fish numbers thus leaving less food equaling less growth??? – who knows. It could be as simple as there is more fish in the bays of where these rivers run out and tucker is harder to come by.
This may be because the rivers are smaller and we can cover the river better with our short casts and heavy flies or just maybe the strain or blood line of the trout is better than other rivers? If it does have something to do with the blood line of the fish then I would think that the trout are coming back to the same river to do their business every season, as it is too much of a coincidence that these rivers continually throw better fish year after year.
In my personal opinion I think that the trout do have some idea of where they were first born and like humans will generally end up where they started. Moving into a river after being in a lake all year must be a big move and it would be reassuring for the fish to be moving into territory or water which it may have smelt before.
Hope this has not caused too many arguments between anglers as everyone has different opinions and some of these questions I have not even thought about before. Hopefully Mike’s answer wont be the total opposite.
Tight lines
Andrew Christmas