:: SALMONIDS ::
The Family Salmonidae consists of the Salmon, Trout and Char,
and is one of the world’s best known families of freshwater
fish. Not only are they highly regarded by anglers as good sportsfish,
but they are also valued both commercially and non-commercially
as an edible fish.
The salmonids are widespread throughout New Zealand but are
not native- they were introduced from the Northern Hemisphere
during the 19th and early 20th Century.
Salmonids occur in fresh, estuarine and salt waters. Some species
move between the different water types, but spawning is invariably
in fresh water. Generally the female excavates a trough (known
as a redd) in the gravel using her tail and deposits her large
orange-coloured eggs within it. At the same time, the male discharges
his milt (sperm) into the redd and the eggs are fertilised.
The eggs take from one to several months to develop into alevins
and after a few weeks turn into fry. This stage is followed
by the parr, smolt and finally adult stages.
Salmon, trout and char are all very similar, but there are some
differences, for example char have extra teeth on the roof of
their mouth.
Did
you know?
If a salmonid has a prominent hook (known as a kype) on its
lower jaw it means it is a maturing male fish.
CHINOOK
SALMON (Oncorhynchus tshawytscha)
Synonymy: Quinnat salmon, King salmon, Spring salmon
Predominantly
silver in colour, with green above and numerous black spots
extending to the tail. Chinook salmon are one of the largest
salmon species, averaging 70-90 cm and 6-8 kg although the largest
New Zealand specimen weighed 29 kg.
| They
are natives of the northern Pacific Ocean and were first
introduced into New Zealand in the mid-1870s. |
 |
Primarily
they are found in gravel rivers on the east coast of the South
Island, but there are populations on the South Island’s
west coast and they are occasionally found around the North
Island.
Mature adults migrate upstream from the sea from late November-March
reaching their gravel spawning grounds around the end of April.
Just prior to entering freshwater they cease feeding and their
tissue deteriorates as nutrients are transferred to developing
reproductive organs. Seventy percent of chinook salmon mature
after three years. After spawning the female often stays and
guards the redd for as long as her strength allows, with the
males moving off in search of further spawning partners. During
the entire spawning process, both sexes continue to lose much
of their condition, and eventually die.
Did
you know?
Chinook salmon are the most successful and common of the Pacific
salmons introduced to New Zealand and are farmed extensively
throughout the South Island.
SOCKEYE
SALMON
(Oncorhynchus nerka)
Synonymy: Blueback salmon, Red salmon, Kokanee
Sockeye
salmon are a brilliant silver in colour and often have several
dark spots on their backs. During spawning their back becomes
a greenish olive and their sides and belly turn a dusky grey.
Sockeye in New Zealand are small fish, reaching about 30cm in
length and 0.5-0.7 kg in weight. They are native to cool rivers
that enter the Northern Pacific and in New Zealand are found
only in the Upper Waitaki River system of the South Island,
where they were introduced in 1902.
| New
Zealand sockeye salmon occur only in a lake-limited form
with the young moving immediately from the spawning stream
into the lakes. |
 |
As the fish grow they feed, mostly during the day, on a variety
of animals including snails, aquatic insects and juvenile bullies.
As they approach maturity, at two to four years of age, the
fish migrate back up through the lakes to the spawning grounds.
The spawning migration takes place mostly in March for a brief
period of only 2-3 weeks. While resident on the spawning grounds
the adults rapidly deteriorate in condition and ultimately die
soon afterwards.
Did
you know?
Virtually all the spawning of sockeye in New Zealand takes place
at one spawning ground at the northern end of Lake Ohau.
ATLANTIC
SALMON (Salmo salar)
Synonymy: Te Anau salmon
The
Atlantic salmon has a brownish back with a few large black spots,
fading to silver on the sides. A native to the cold areas of
the North Atlantic this species was first introduced to New
Zealand in 1868 and by 1910, nearly 5 million eggs had been
imported.
| Unfortunately,
sea-run populations failed to develop and today Atlantic
salmon can be found only in Southland and are entirely confined
to freshwater. |
 |
Spawning of New Zealand Atlantic salmon occurs primarily through
May and June within the lake tributaries. The young may stay
to feed and grow in the rivers for up to five years before moving
down to the lakes, but most migrate at between one and three
years of age. They mature in the lakes and apparently spawn
annually for as long as they survive (up to five times). Most
spawn for the first time at age four and after this first spawning
it appears that Atlantic salmon virtually cease to grow.
Did
you know?
In New Zealand, the average Atlantic salmon weighs 1-2 kg and
is about 83cm in length but in their native waters they can
attain a huge size of at least 150 cm and 38 kg!
LAKE
CHAR (Salvelinus namaycush)
Synonymy: Lake trout, Mackinaw, Great Lakes char
Lake
char have an olive/grey back, paling to white underneath and
are covered with irregular white to yellowish spots. They are
a cold-water fish and are native to North America. They were
introduced into New Zealand in 1906 and today survive only in
Lake Pearson in the South Island. They normally live and feed
in deep water so consequently conditions in New Zealand are
not ideal, resulting in many elongate, thin fish in poor condition
that average only 40 cm in length and 0.6 kg in weight (They
can grow to 127cm and 46 kg in North America!).
| Spawning
in mackinaw is different from that in most salmonids as
redds are not constructed. Instead spawning occurs at night
when the eggs are dropped over rocky areas on the lake floor. |
 |
Discharge of the eggs is not random and evidence exists that
the fish return annually to the same area and maybe even home
back to where they originally hatched themselves. The mackinaw
grows slowly and commonly lives 10-15 years but some may exceed
40 years.
Did
you know?
A splake is a hybrid between a female mackinaw and a male brook
char. These dark fish have red tinges on their fins and are
not a natural species. They were bred as an alternative game
species and were released in two areas of the South Island.
Little is known about the state of the wild stocks, with only
one known population found in the South Island’s Lake
Letitia, and their future in New Zealand remains uncertain.
BROWN
TROUT (Salmo trutta)
The brown trout has a variable colour pattern, but is usually
olive-brown with large dark brown spots and a lighter belly.
Brown trout are native to Europe, but have been liberated in
nearly 40 countries worldwide.
| They
were first introduced into New Zealand in 1867 and today
are widespread throughout the North and South Islands. |
 |
There are sea-run, riverine and lake dwelling brown trout populations
throughout New Zealand and it is thought that interbreeding
occurs between the distinct groups due to occupation of the
same spawning grounds. Essentially the life cycle is the same,
the adults spawn and the young remain in freshwater from anywhere
between a few months to three years, then they migrate either
to the sea or into the lakes. Sea run fish grow to a greater
size due to an abundance of accessible food (more females migrate
out to sea than males, enabling them to grow larger and produce
more eggs). Brown trout are highly territorial with generally
the biggest fish holding the best feeding position. These monsters
have been known to weigh up to 17 kg!
Did
you know?
Sea-run brown trout travel considerable distances- one tagged
fish was shown to have moved at least 230 km over a 125 day
period!
BROOK CHAR (Salvelinus
fontinalis)
Synonymy: Brook trout, Fontinalis or Fonti, Eastern American
char, Mud trout
These
brightly coloured fish have dark olive-green marbling on their
backs, and dorsal and tail fins. The remaining fins are a grey-orange,
each with a bold white stripe along its leading edge. They can
reach 60 cm in length and 3 kg in weight within New Zealand,
but most populations rarely exceed 20 cm and 2 kg.
| A
native of North America, these fish were introduced in 1877
and are found quite widely throughout New Zealand, but only
as freshwater residents. |
 |
Brook
char inhabit small lakes and small, narrow upland streams. This
is because they cannot normally coexist with other salmonids,
especially the aggressive brown trout, and this potential competition
prevents them from becoming more widespread.
Their spawning behaviour is not completely known in New Zealand
but it is thought that it occurs in fine gravel around the lakeshore.
Did
you know?
The largest brook trout specimens in New Zealand are found in
Lake Emily, an inland Canterbury lake which contains a significant
little fishery!
RAINBOW TROUT
(Oncorhynchus mykiss)
The
rainbow trout is a predominantly silver fish, with an olive/grey
back, white belly and a distinctive pink-red stripe along its
sides. Rainbow trout are native to the Pacific coast of North
America and were thought to have been introduced into New Zealand
in 1883 from California.
| Most
rainbow trout in New Zealand are lake populations averaging
fish of 50-60 cm and 2-3 kg, but certain populations are
managed as trophy fisheries and fish here can reach 4-5
kg. |
 |
Spawning in rainbow trout within New Zealand takes place in
late autumn and through the winter. The adults spawn in lake
tributaries and the young remain near the spawning grounds until
they gradually move downstream to the lakes, at an age of about
a year. They mature in the lakes for two to four years until
ready to spawn when most of them will return to the streams
where they themselves hatched. Rainbow trout are carnivorous
and feed on a variety of animals from floating terrestrial insects
to small fish.
Did
you know?
Shags, longfinned eels and even stoats have been known to prey
upon rainbow trout but it has never been proven that these have
a significant impact on the population.
