Kokanee salmon belong to the same species as sockeye salmon (Oncorhynchus nerka), but when sockeye migrate to the
ocean to grow to maturity, Kokanee remain in lakes. Sockeye are referred to as anadromous fish while Kokanee are landlocked.
Many lakes and streams in BC support both Kokanee and sockeye; sometimes they spawn side by side. Others support only sockeye
or only Kokanee. Present scientific information suggests that Kokanee arose from sockeye in each system into which sockeye
established a population. After the last ice age some 10,000 years ago, Columbia River sockeye are suggested to have migrated
into what is now the Okanagan, and established a sockeye population. Kokanee populations then evolved off the sockeye
population. Later, when access upstream into the Okanagan was blocked, the sockeye population disappeared, leaving the
Kokanee population we see today. Similar patterns of Kokanee establishment are suggested for the Arrow and Kootenay lake
systems. Thus the Kokanee of Okanagan Lake are more related to sockeye of the Columbia River than to the Kokanee of Kootenay
Lake. This implies that each lake's Kokanee population is evolved for that specific lake, and is therefore uniquely adapted
to that lake.
Okanagan Lake supports two types of Kokanee salmon - the stream spawners and the lake shoreline spawners or beach spawners.
During their entire feeding life the two types mix in the lake. At sexual maturity, usually at age three (three years after
being laid as eggs), they undergo a spawning migration, spawn, and die. Stream-spawners migrate into some 14 lake tributaries
in early September and complete spawning by mid-October. Shore-spawners migrate to spawning beaches along the lake shoreline
and spawn from mid-October to mid-November. ( Fig 1 )
The two types of Kokanee appear to be reproductively isolated. Recovery of spawning adults that were tagged during their
fry outmigration from Mission Creek suggested most returned to their natal area, some strayed to other tributaries, but none
spawned along the lake shoreline. Study of genetic material (mitochondrial DNA) enabled no genetic separation of fish among
tributaries, or among shore-spawning areas, but separation between stream and shore ecotypes. If combined with their temporal
and spatial separation at spawning this evidence strongly suggests that shore-spawning and stream-spawning Kokanee are
- scientific name: Oncorhynchus nerka kennerlyi
- "Kokanee" is a native word meaning "red fish"
- a type of sockeye salmon
- referred to as "landlocked" sockeye salmon because they spend their entire life in freshwater differing from the anadromous sockeye salmon which spends part of its life in the river and then the ocean, after which it returns to its home river to spawn
- native to British Columbia, Alaska, Washington, Idaho, Siberia and Japan
- Okanagan, Kalamalka and Wood lakes are unique in that they have both stream and shore spawning populations of Kokanee salmon
- two distinct populations of Kokanee salmon in the Okanagan: stream spawners and shore spawners
- common Names in the Okanagan Valley: Kokanee, kickininee, little redfish, landlocked salmon, Kennerly's salmon, silver trout, yank
- silver on sides with a bluish-black top and white on stomach
- body color changes during spawning season
- those that change the most have green heads and bright red sides
- 3 layers of muscle in salmon body -- white, pink, red
- red or lateral muscle: found along sides, just under skin
- high fat content used in steady, untiring swimming activity during migration
- scales are embedded in the skin and protected by a thick coat of mucus
- smaller than the ocean sockeye salmon
- fish hearing is limited to sound waves in water.
- pores in a canal run along the sides of the salmon contain motion sensitive hair cells. This structure is called a lateral line
- senses water movement
- detects moving objects
- used in schooling
- salmon have no eye lids
- the pupil of the eye is large and does not change shape like in humans so the salmon tend to avoid bright light
- they can perceive colors
- they detect odors by using sacs inside the snout
- these organs of scent are known as an olfactory system and are used for:
- predator avoidance
- migration direction
- mate choice
Biology: Life Cycle
- FOOD SUPPLY
Kokanee compete for zooplankton with species such as the freshwater shrimp (Mysis relicta), Rainbow trout, whitefishes, northern squawfish and suckers. A low food supply reduces the Kokanee growth rate resulting in insufficient body reserves to survive their first winter.
- PREDATION ON KOKANEE
Large Rainbow trout feed exclusively on Kokanee, therefore the Kokanee must avoid the trout in order to survive.
Most of the decaying vegetation and other waste products carried down by the streams during spring runoff are in a form not immediately available for plant growth.
Such materials may settle out before they are decayed, and they become locked in the bottom sediments of a lake and therefore can not be utilized.
The level of Okanagan Lake's productivity is known as being oligotrophic (nutrient poor).
- AGE DETERMINATION
Scales & otoliths (inner ear bones) are used to determine the age of a salmon.
The scales of the salmon grow and as they do they form rings just like those of a tree trunk.
These rings form bands which can be counted. The widely spaced rings occur in the spring and summer months when food supply is abundant, while the more tightly packed rings indicate the winter months when growth is slow from limited food supply.
Digging a Redd
September and October, year 1:
A female Kokanee contains between 250 and 2000 eggs which she will deposit in two to three nests,
called redds, at spawning time in the late autumn. Over the winter months, the eggs develop and in
February they hatch into tiny fish called alevin. The alevin remain in the gravel for one to two
November to March, year 1:
During their time in the gravel the alevin do not feed. They receive nutrition from their large yolk sac until
the time when they emerge from the gravel as fry, sometime between March and early April.
Yearling: March, year 1 to March, year 2
Fry: March, year 2 to March, year 3:
The fry typically emerge from the gravel at night and are immediately swept downstream with the spring runoff
water. Once in the lake, they feed on plankton and small attached organisms along the lakeshore. By the following
spring, they have grown to a size which classifies them as yearlings. It will, however, take them three years to
March, year 3
(sometimes to March year 4, March year 5):
By three years of age, Kokanee contribute to the sports fishery. The catch record for a "silver", the local name often
used for them at this age, is 9.8 pounds. Typically, by year three, they become mature and may begin a spawning migration. Some, however, migrate at four or five years in age.
The age of a Kokanee is sometimes determined by examining its otolith (inner ear bone), but more often, it's easier to
tell the age of a salmon by looking at its scales. As the scales of a salmon grow they form rings, just like a growing
tree. These rings form bands which can be counted. The bands even correspond to how much food the Kokanee is getting.
They are widely spaced in the spring and summer months when food supply is abundant. The more tightly packed rings
indicate the winter months when growth is slow, because of a more limited food supply.
Jacks: Kokanee that reach maturity by year 3
(Most Kokanee reach maturity between April and March of year 4):
Upon maturity, Kokanee become red over most of the body. The male develops a long, hooked jaw and a slightly humped
back. They migrate into streams in August of their maturing year. By this time, both male and female stop eating.
By spawning time much of the body mass has been converted to energy for migration and spawning, or to sperm or eggs.
Even the fish's scales are absorbed.
September and October, (usually) year 4:
Kokanee, like other salmonids, are capable of returning to the stream of their birth using their acute sense of
smell. Having arrived at a suitable site, the female begins to dig a nest called a redd. She turns on her side
and violently flips her tail to move gravel downstream. The redd may be six to twelve inches deep.
September and October, (usually) year 4:
While the female is digging the redd, the males court the female. When the female is ready to spawn, she
permits a male to join her in the redd. After a courtship that involves a series of subtle moves, both fish
quiver and shake as the eggs and sperm are simultaneously released. The eggs and sperm mix in the water as
they drop between the gravel crevices in the redd. The female then gently covers the eggs by moving gravel
into the redd before moving to another nesting site. The female will dig two to three redds before all her
eggs are spent. She will not necessarily spawn with the same male at each redd. Both adults will die within
days of spawning.
Illustrations by Murray Johnson