The Salmon In Bowker Creek

by OB 2020-04

This playlist talks about the salmon in Bowker Creek. Topics go from the different types of salmon, to problems of why the creek is not currently suitable for the fish.

What Are Salmon?
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The salmon are a type of Pacific fish. In their life, they travel to the ocean when they are old enough. After a while, they return to their natal water to make a redd to spawn. When they spawn, they die. Adult salmon do not eat while breeding, but their babies eat plankton, invertebrates, and insects. There used to be coho and chum salmon in Bowker creek before it was urbanized. They were used in the First Nations culture for storytelling, and food. However, there is no more salmon at the creek anymore.

The Salmon Cycle
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Salmon start as eggs. They then turn into alevins (Newly spawned salmon.), fry (Newly hatched fish.), parr (Young salmon between fry and smolt that have dark round areas on its sides.), smolt (Turns silver and travels to the sea.), and finally into adult salmon. (In the respective order.).

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Coho is a type of salmon that is 3.6 - 5.4 kg, and are 20 - 30 cm in length. They are also called the “Blueback”, “Sea Trout”, “Silver Salmon”, and the “Oncorhynchus Kisutch” (Scientific Name). Before traveling to the ocean, Coho salmon spend at least one Winter in freshwater. In the ocean, they spend 2-3 years of their life before going back to their birth location to spawn. They lay around 2,400 to 4,500 eggs.

Coho Spawning Criteria
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There are four spawning criteria for coho salmon. 1.) The depth of water over the spawning gravel has to be from 15.2 to 54.8cm. 2.) The velocity of water has to be from 22.8 to 91.4cm per second. 3.) The temperature has to be from 3.3 to 12.7 degrees.4.) Gravel has to be from 1.27 to 7.62cm in diameter.

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Chum is the second most common type of salmon, that weigh around 5.4kg to 6.8kg, and are 89-114 centimeters long. They hav eblack speckles on their backs, and a metallic-blue colour in the ocean. They are also called the ‘Dog Salmon’, ‘Calico Salmon’, and the ‘Oncorhynchus Keta’ (Scientific Name). Although they leave their birth streams early, they are the last Pacific salmon to go back to their natal water to spawn. They lay around 2,400-3,100 eggs in their redds.

Chum Spawning Criteria
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Chum salmon spawn when they are 2-7 years old (average 4). They reach their spawning area in November - December. Most of the time, they spawn in small streams and intertidal areas. They prefer medium water flow.

Why Are There No Salmon At Bowker Creek Currently?
There are no salmon in Bowker Creek. This is because there is too much nitric acid, and too little dissolved oxygen in the water for salmon. This nitrate comes from fertilizers, used in gardens. A solution for reducing nitric acid in the creek is for people to use nitrate free fertilizers. Another reason is because of the pollution in the creek. There are signs of species such as aquatic worms, leeches, and sticklebacks, that have high pollution tolerance. The level of pollution needs to be reduced for salmon to come back. In short, if these conditions were better, the creek could be a good place for the salmon.  

Problems For The Salmon
Salmon can swim through most of the tunnels in Bowker Creek. However, there is a tunnel under Fireman’s Park that is sloped. Because of the angle, it would stop salmon from swimming up it. In the tunnel, a fish ladder would need to be put for salmon to swim in the creek.

Fish Ladder
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A fish ladder for the salmon to use in the tunnel at Fireman’s park.

How Would Salmon Help The Ecosystem?
Dead adult salmon will be eaten by other animals such as hawks, eagles, and racoons. Because of this, the salmon will provide an alternate food source for these animals. This would make the wood web more sustainable, and less likely to break in case a species becomes extinct.  

Who Can Help The Salmon Restoration?
Lots of people would need to support Bowker Creek, for it to be restored. This is because the creek is not currently in a suitable condition for the salmon, and lots of help would be needed to fix this. Once restored, the creek may be able to bring back salmon. Some people who can help are: ‘Friends Of Bowker Creek’, ‘CRD’, ‘Oak Bay High”, and the “Greater Victoria Green Team”.