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Saturday, May 22, 2010

Salmonids

There are five species of Pacific salmon that die after spawning; Chinook, Chum, Coho, Sockeye, and Pink. Salmon return to their natal streams and rivers each year. Salmon travel thousands of miles and spend one to five years feeding in the ocean before returning to their birth streams. Spawning females dig out a gravel nests, called a redd. The males then fertilizes the eggs and the female protects the redd for one to two weeks. Alveins hatch and mature into fry, developing vertical bars for camouflage, called parr marks. After a period of feeding fry migrate downstream towards the ocean and grow into smolts adapting to their marine environment.

Chinook
Oncorhynchus tshawytscha
Spring, Salmon, King, Blackmouth,
Quinnat, Chub, Tyee (14+kg)
Chinooks have a greenish-blue dark back with
long black spots, a red hue develops around
the fins and belly, male teeth are enlarged and
they have a hooked snout. Tyee reach 1.5 m
and 58 kg, average 90 cm and14 kg. Spawning
peak May to June and August to September.

Chum
O. keta
Dog Salmon
Females are a metallic
blue, males have a
checkerboard colouration,
a dark horizontal stripe, and
canine-like teeth. Average
from 4.5 to 12 kg. Spawning
peak month October.

Coho
O. kisutch
Silver Salmon
Spawning males are red on
their sides, and a bright green
on the back and head areas, with a
darker colouration on the belly, spots
on upper tail fin lobe. They also develop
a hooked jaw with sharp teeth. Females
develop a lesser-hooked snout. Coho
reach 1 m and weigh up to 14 kg, they
average between 3 to kg. Spawning
peak July to August.

Sockeye
O. nerka
Kokanee, Red Salmon,
Blueback Salmon
Varying shades of red resulting
in a brilliant scarlet fish with a
green head. Grow to 83 cm
and weigh up to 7 kg. Spawning
peak month August.

Pink
O. gorbuscha
Humpies
Pale grey, males
develop a hump.
Get up to 76 cm
and to 5.5 kg,
average 1.5 to 2.5 kg.
Spawning peak month
October.

Threats
On top of natural dangers from predators dangers to salmon from human activities include poor farming and forest practices, pollution, destruction of coastal wetlands and estuaries. The territory of British Columbia salmon has been decimated for decades by industrial clearcut logging. Roots of trees anchor steep slopes. Logging increases the chances of landslides filling vital spawning grounds with mud, debris, and boulders. Shade from trees is lost increasing water temperatures. Other threats include overfishing, urbanization, hydroelectric dams, and fish farms.

Actions
Salmon play an important role sustaining forest ecology. Spawners bring vital nutrients from the ocean into the forest. Carcasses are dispersed by bears and eagles providing the trees with fertilizer; nitrogen, phosphorus, and carbon. Salmon feed the rivers helping the survival of young salmon. Farmed salmon does not replicate this vital role and is detrimental to wild stocks. Dangers from fish farms include disease, pollution (including contaminating shellfish), predation on young wild salmon, and escapement (Atlantic salmon compete for food and habitat with wild stocks). Conservation actions include cleaning up salmon streams (ensuring clean and safe flowing environments), recycling, using biodegradable/organic products, and choosing wild salmon over farmed.

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