I have just spent a week or so fishing the Twizel
Canals. Fishing was pretty hard and not
a lot of salmon were being caught though we did witness a 30.5lb brown hen
landed and released on the Tekapo Canal.
We caught several silver salmon, a rainbow, a brown and a few spawning
salmon on softbaits and had a great time in good weather and breath-taking
scenery although the cold was hard for a North Islander to handle.
I have an interest in our freshwater fish biology and have
some questions as to the sustainability of this canal fishing. My understanding was that the rainbow and brown
trout were stocked occasionally and that the salmon were from escapees from the
fish farms. However, after discussions
with what seemed to be knowledgeable anglers met on the canals, they say that
the rainbow and brown fishery is not stocked and that these fish are spawning
in the canals. This is because there are
so many smaller rainbows seen and caught.
Other anglers also say the salmon are also self-sustaining. In particular in April-May at the Ohau
control gates there are massive 20lb plus rainbows in spawning condition caught. There are also many spawning salmon that the
locals call “manky salmon” which are brown, blotchy and apparently inedible and
are in physical decline. However, these
are still fairly hefty fish of at least 10lb of so and are not easy to land in
the fast water if fishing too light (say less than 10lb trace). One angler I met said that the large rainbows
and salmon can pass upstream through the Ohau control gates and end up spawning
in Lake Ohau’s tributary streams or the lake itself. If this is occurring at the Ohau Canal
control gates then maybe it also occurring on the Tekapo and Pukaki control
gates too? The implication being that
the canal fish are able to spawn in those lakes too (Pukaki and Tekapo). Maybe the rock flower inhibits this activity
in these lakes?
I also have a question as to the type of salmon in these
canals. I understand the salmon farmed
on the Tekapo and at Ruataniwha farms are chinook and the same fish as available
in the self-sustaining fishery on the east coast rivers. But I see a sign on the Ohau Canal fish farm that
says “sockeye” salmon – does this mean that those manky salmon at the Ohau
control gates are sockeyes? Do chinook end
up in this hump-backed brown spawning state?
These are questions that came to mind when fishing these canals.
I would love to see a dialogue about this fishery and
comments on these sustainability aspects.
Are there any fisheries scientists that know what is going on here? I look forward to seeing a discussion on this
forum.
JezzaDun wrote: you'll be surprised how little the artificial food source in the canals plays a part in the size of these fish. |
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