* Lake Taupo is an internationally renowned trout
* The fishery is of great importance to Ngati Tuwharetoa.
* In 1991, 13% of all anglers (marine and freshwater)
who fished in New Zealand fished at Taupo.
* Taupo anglers comprised 42% of all freshwater anglers
and spent approximately $70 million using the Taupo
of the fishery
were introduced to the Taupo District to provide a
sports fishery. Brown trout were introduced into the
lake in 1887 and quickly grew to large size but were
difficult to catch. As a consequence rainbow trout
were introduced in 1898. Although in the early years
the size and condition of the fish fluctuated, over
the past 40 years this has stabilised and the Taupo
Fishery continues to provide excellent fishing opportunities
A description of the fishery
Taupo Sports Fishery Management Plan requires the
fishery to be managed as a self- sustaining wild trout
fishery. No stocking is undertaken.
Trout spawn in the
tributaries of the lake and the young that hatch spend
the next 18 months or so in the streams before migrating
to the lake. Once in the lake the fish grow rapidly
by feeding principally on smelt. Most mature at approximately
three years of age and 2 kg in weight. As winter approaches
these fish run back up the rivers to spawn, 30% surviving
the rigours to spawn a second time.
anglers fish for trout in the lake and over winter,
target the spawning trout in the rivers. Approximately
45,000 anglers use the fishery each year catching
in the order of 150,000 to 175,000 legal sized (>45cm)
trout. Slightly over half of the total angling effort
of approximately 650,000 hours is expended on the
The fishery is managed by the Department of Conservation
as a consequence of an agreement between the Crown
and Ngati Tuwharetoa enshrined in the Maori Land Amendment
and Maori Land Claims Adjustment Act 1926. Management
is self- funded from fishing licence revenue which
this year will be in the order of $1.5 million.
What limits the fishery?
The relatively pristine nature of the streams
and lake provide exceptional spawning and rearing
habitat, but the environment can also be very harsh.
Only one fish from every thousand or more eggs will
survive to maturity. The wide range of stream types
and diversity of life history patterns amongst Taupo
trout is a major strength of the fishery, making it
resilient to adverse climatic and environmental impacts.
The key constraints
on the size of the trout population are:
* Spawning success
* Juvenile survival - the first few days after emergence
constitute the single largest source of mortality
when more than 90% of fry are frequently lost. If
dramatic events like floods occur then the mortality
will be even higher.
* Size on lake entry - the larger the juvenile trout
is on entering the lake, the greater it's chances
of survival. The number and quality of large juveniles
is initially controlled by the number of fry that
survived and subsequently by the quality and quantity
of the food and habitat available in the rivers.
Ultimately, the size
of the adult trout population in the lake varies widely
from year to year in response to the prevailing climate
and living conditions during the river growing phase
of the fish.
This variation is
one of the intricacies of managing a wild trout fishery.
Future threats to the fishery
1. Reduction in quality
or extent of spawning and rearing habitat. Taupo streams
provide extensive areas of good living conditions,
but this environment can be easily damaged.
2. Reduction in trout growth and/or numbers caused
by water quality change. Changes in water quality
are being caused by increases in nutrient content.
This is likely to be detrimental for the fishery.
3. Negative impacts arising from the introduction
of new species. The risk of accidental release of
an undesirable new species or disease appears low.
However if a new species does become established,
eradication is unlikely to be an option and the potential
impact on the fishery could be significant.
4. Overharvest. Overharvest in Lake Taupo can have
a significant impact on the number of fish surviving
to maturity and in the worst case the sustainability
of the fishery will be threatened. Significant poaching,
if left unchecked, could have a similar effect.
5. Releasing of fish - anglers are required to release
fish that are undersize and many anglers choose to
release fish that are in poor condition and not suitable
for the table. Unfortunately rough handling of fish
prior to release increases the mortality rate and
many fish do not survive. The DOC encourages anglers
to land fish quickly, ideally leaving them in the
water and unhooking them without touching or handling
to help ensure their survival.