Home' Fish and Game : September 2016 Contents Central South Island Region
HE MACKENZIE BASIN HYDRO CANALS
are gaining a well-deserved reputation for
consistently producing huge fish. The canals
are easy to access, flow through spectacular high
country scenery and are open all year round.
Add to this the fact that anglers have the chance
to catch three species of sports fish and you have a
recipe for a ‘bucket list’ fishery.
Over the course of the 2015-2016 season, Fish
& Game rangers were highly active at the canals
checking angler compliance and undertaking a
survey of just how many fish were being harvested.
At the time of writing, surveys have been
completed from the months of October 2015 to June
2016 and the information gathered so far is worth
ETWEEN 1976 AND 1986, SIMULTANEOUS
spawning surveys of the Waitaki and Hakataramea
rivers established a relationship between the
Hakataramea spawning run and the rest of the Lower
Waitaki catchment. This meant the size of the annual Waitaki
run could be more easily estimated from surveys of just the
However, this is no longer valid because since 1998, low
flows have been increasingly common on the Hakataramea
River, creating barriers for the upstream migration of salmon.
FISH & GAME OFFICER HAMISH STEVENS RETURNS A
‘TYPICAL’ RAINBOW TROUT BACK TO THE CANALS AFTER A SALVAGE OPERATION
1. The canals are a popular place to fish. On a holiday
weekend, for example ANZAC weekend 2016, more
than 500 anglers fished throughout the canals system
2. Canal anglers are hardy. Despite dust storms, hail or
blistering sunshine, at any time, on any day, there are
always at least a dozen anglers fishing the canals.
3. The salmon fishery relies on salmon escaping from
the salmon farm pens. Two of three fish caught by
anglers are salmon, even in seasons like 2015-2016
when big schools of salmon escaping from the farms
were rare events.
4. The catch rate is higher in the cooler months.
5. On average, approximately four of 10 rainbow trout
caught weighed 10lb or more, while two in 10 brown
trout caught weighed 10lb or more.
6. One in 10 rainbow trout caught weighed 20lb or
more. Salmon and brown trout in this size range do
get caught at the canals, but not very often.
7. Approximately 1% of all anglers encountered
by rangers are found to be fishing without a
CENTRAL SOUTH ISLAND 2016 SUPPLEMENT
BY RHYS ADAMS, FISH & GAME OFFICER
Over the last five years
extensive aerial surveys of
salmon spawning in the
Lower Waitaki catchment
have been undertaken to
identify how much of the
total catchment’s spawning
is occurring in key spawning
areas. By establishing just what
this proportion is, the total
catchment’s spawning can be
estimated by scaling up the
results from those key areas.
These widespread surveys
have also been used to identify
streams which could be
enhanced to improve spawning and juvenile rearing habitat.
We have estimated the number of salmon spawning
redds (salmon nests) in the lower Waitaki River catchment,
excluding the Hakataramea and Maerewhenua rivers, from
2012 to 2016 were; 629, 782, 545, 461, and 580.
Historically, extensive aerial surveys of salmon redds
in the lower Waitaki catchment have been undertaken
on 11 occasions since 1976 and with the addition of the
Hakataramea index, estimates of Waitaki River redd counts
are available for 20 years since 1976.
REGULATION CHANGES FOR 2016-2017
• Bait fishing from boats permitted in Lakes
Benmore and Ohau.
• Fly fishing only status is retained for lakes Poaka,
Mystery, Roundabout and Emily and their tributaries,
Maori Lakes and their tributaries and Ahuriri River
Lagoons. All other fisheries to become fly and spin,
or fly, spin and bait.
OBSERVATIONS FROM THE CANALS
Redd counts showing fewer than 1500 redds in a season
can be considered poor, while around 2500 redds is indicative
of the Waitaki salmon fishery being in its historical average
range. The 2016 count of 580 is well below the level indicative
of a healthy fishery.
Fish & Game is committed to ensuring the sustainability
of the Waitaki salmon fishery and as part of an agreement
between Meridian Energy and Fish & Game, a joint salmon
project has been underway since 2010. The project aims to
increase the natural production of wild juvenile salmon by
enhancing salmon spawning and rearing habitat in stable side
braids of the lower Waitaki River.
As part of the project, in the last year, willow growth which
has swamped side stream habitat has been removed from
a total of 2.1km of spawning bed at Wilson’s Road, Black
Point Stream and near the Lower Waitaki Irrigation Scheme
overflow. Spraying of willow regrowth on approximately 4km
of previously cleared side streams opposite Duntroon and
at Priests Road was also completed. All of these works were
undertaken by ECan river engineering staff.
Looking forward, Fish & Game and the Lower Waitaki
Irrigation Company are considering modifying part of an
irrigation structure to provide access for adult salmon to a
previously closed section of spring-fed stream of about 2.5km
with potential new spawning habitat for up to 200 salmon.
TWO SIDE-STREAMS CLEARED OF WILLOWS BELOW BORTONS POND
ARE THE SEASONS CHANGING?
ANGLERS MINGLING ON THE RIVERBANK OFTEN
come up with some interesting theories about
salmon. Some examples are “the icebergs off the coast are
cooling the water and this will bring the salmon in”, or “the
salmon run is getting later”.
While we cannot provide any evidence to support the
iceberg theory, we do know what is happening with the
timing of the spawning runs.
In the Rangitata River, spawning salmon have been
counted annually since 1993. The survey consists of five
BY HAMISH STEVENS,
FISH & GAME OFFICER
aerial counts between the end of March and the
middle of June.
Prior to 2006, the average peak run was on April
21 for Deep Creek and the April 17 for Deep Stream.
Since 2006 the average peak run has been on April
22 for Deep Creek and April 14 for Deep Stream.
Therefore, over that 24-year period the timing of
the peak spawning run has not changed significantly.
What is apparent is that the Rangitata peak spawning
run has been more variable since about 2003.
While we have no information to explain this, we’ll
look forward to hearing some interesting theories on the
riverbank next season.
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