Cowichan Watershed Board

  • Email
  • Facebook
  • RSS
  • YouTube
MENUMENU
  • About
    • Collaborative Governance
    • Our Principles
    • Board Members
    • Staff Team
    • Non-Profit Society
    • Supporters (Coming Soon)
    • Contact Us
  • Targets
    • Water Quality
    • Estuary Health
    • Salmon Sustainability
    • Wise Water Use
    • Watershed Connections
    • Water Flows
    • Riparian Plants
    • Target Working Groups
  • Projects
    • Drought Response
    • River Cleanup
    • Koksilah
    • Twinned Watersheds Project
      • Riparian Plants
      • Indigenous Flows
      • Fish Habitats
      • Big Dancing Fish
    • Weir Ready
      • Weir Ready FAQ
    • Speakers Series
    • Past Projects (Coming Soon)
      • Water Challenge (Coming Soon)
      • Superheroes (Coming Soon)
  • Library
    • Board Meetings
    • Governance Documents
    • Maps
    • Media
    • Presentations
    • Videos
    • Reports
      • CWB Reports
      • Other Reports
    • All Library Items
  • Latest News
You are here: Home / content / Fish in the Cowichan Watershed

Fish in the Cowichan Watershed

October 8, 2010 by Jill Thompson

FishSpeciesInCowichanWatershedThe Cowichan Watershed is home to many fish species. This is a function of both the size of the watershed and its incredible ecological richness as habitat and in terms of nutrients.

The ecological health of the watershed is reflected in the health of its fish. It’s a mutual relationship. Healthy fish make a healthy watershed, and vice versa.

Click here for a table listing the fish in the Cowichan Watershed. The table shows fish presence recorded in a number of streams and three lakes in the watershed, and indicates whether they are exotic/introduced species, and shows their BC Conservation and COSEWIC status.

On this page we look at a few representative fish of the Cowichan Watershed, including some “Salmonids”, which are the most abundant and ecologically and economically the most important fish, at “Exotic/Introduced” species, and a couple of “Rare or Endangered” fish.

“Anadromous” is the term used to describe fish which spend some part of their lives in fresh water and some in salt water. Salmon are anadromous.

It is fascinating fact that within the same species fish, some are anadromous, and some live their entire lives exclusively in fresh water. Coastal Cutthroat is an example. Oncorhyncus mykiss the Rainbow Trout is another. Cowichan is also home to Kokanee, the fresh water variant of Oncorhyncus nerka, but the watershed does not have an established run of Sockeye Salmon, the anadromous fish.

The most plentiful salmon in the Cowichan system are Chum salmon, which annually appear in the tens of thousands. Whenthey die after spawning they contribute hundreds of thousands of kilograms of nutrients to the watershed. Recently only a few thousand Chinook and Coho have been spawning in the watershed.

SALMONIDS

Salmon

ChinookSalmon_descChinook (Oncorhynchus tshawytscha)
– At least 1 year in fresh water; 1-5 years in the ocean.
– Largest of the Pacific salmon, highly important sport fish.
– International “indicator” fish.
– Historic low populations in Cowichan in the past several years: low thousands in recent years versus tens of thousands in 1970s.

ChumSalmon_descChum (Oncorhynchus keta)
– Fry leave almost immediately for the ocean, return after 2 to 6 years.
– Most abundant salmon on Pacific coast, numerically and in terms of body mass.
– Described as a “marine nutrient pump” as they aggregate marine nutrients and transport them into coastal watersheds.
– High spawner returns in Cowichan: avg 150,000 per year in recent years

CohoSalmon_descCoho (Oncorhynchus kisutch)
– 1 to 2 years in fresh water and 18 months or so at sea.
– Tend to hang around coastal areas rather than heading to deep ocean
– Excellent and abundant sport fish
– Historic low populations in Cowichan: low thousands in recent years versus tens of thousands in 1970s.

Kokanee_descKokanee (Oncorhynchus nerka)
– Maximum length: 60 cm.
– Kokanee are Sockeye salmon that spend their entire lives in fresh water.
– Kokanee eat zooplankton, not other fish.
– A Rainbow trout will eat two Kokanee a day.

 

Steelhead_descSteelhead (Oncorhynchus mykiss)
-searun rainbow trout
-1 to 5 years in fresh water, 1 to 4 years at sea
– Cowichan steelhead are winter-run (return late December to March)
– Returns 500-800 per year over last ten years, likely 2000 or more in 1980s
– High value sport fishery

 

Trout

CoastalCutthroatTrout_descCoastal Cutthroat (Oncorhynchus clarkii clarkii)
– Maximum length: 76 cm.
– Anadromous and freshwater forms.
– Blue-listed (vulnerable) in BC.
– Particularly at risk on east side of Vancouver Island, where many runs are
already extinct.
– Dependence on small streams for spawning and rearing makes them especially
vulnerable.

BrownTrout_descBrown Trout (Salmo trutta)
– Can exceed 50 cm.
– Popular angling fish on the Cowichan River.
– Brought to North America from Scotland in 1884.
– Introduced to BC as hatchery fish in 1932.

 

RainbowTrout_desc•Rainbow Trout (Oncorhynchus mykiss)
– Maximum length: 90 cm.
– Coastal type found in all of BC’s coastal rivers.
Char

DollyVarden_desc•Dolly Varden (Salvelinus malma)
– Up to 45 cm
– Blue-listed (vulnerable) in BC.
– Anadromous and freshwater forms.
– The only fish on this page named after a Dickens character.

 

RARE/ENDANGERED SPECIES

CowichanLakeLamprey

Cowichan Lake Lamprey (Lampetra macrostoma)
– Up to 26 cm.
– Found only in Cowichan Lake and Mesachie Lake – and nowhere else on Earth.
– In one study in Mesachie Lake, as many as half the salmon and trout sampled had scars from lampreys.
– It is locally abundant, and does not seem to be under obvious threat. Due to its extremely limited range it is red-listed in BC and has been designated as Vulnerable by COSEWIC

ALIEN/EXOTIC/INTRODUCED SPECIES

PumpkinseedSunfishPumpkinseed Sunfish (Lepomis gibbosus)
– Rarely exceed 20 cm.
– Native to eastern and central North America, alien species in western NA.
– Threat to freshwater biodiversity and to indigenous fish species in BC.
– At present only recorded in Somenos Lake in Cowichan Watershed

Brown Trout see above, in Trout

 


Related Resources

Fish – A Cowichan Watershed Overview
Tom Rutherford, July 2010

Pacific Salmon
Fisheries and Oceans Canada

Sport Fish of B.C.
B.C. Fish Facts
BC Ministry of Environment

 

 

Filed Under: content

Join us at the Speaker Series!

Speaker Series audience - B Hetschko

Come Learn with Us! Click here for the Speaker Series.

Weir Project Website

screenshot cowichanlakeweir.ca

Click to visit the weir project website.

Watershed Board Meeting Info – click image.

CoChairs Daniels and Segall

Click image for Board Meeting Packages. Photo of CWB Co-Chairs, Cowichan Tribes Chief Cindy Daniels, CVRD Chair Kate Segall (Cowichan Tribes photo)

Why Fish Need Water

Why Fish Need Trees

Why Fish Need People

Latest News

  • [Times Colonist] Comment: Let’s give a dam for Vancouver Island’s only heritage river
  • [The Discourse] Local advocates look ahead to a healthier year for Somenos Lake
  • Why BC Needs Watershed Boards
  • [Cowichan Valley Citizen] The 14th annual Lower Cowichan River clean up is back on Aug. 25

Sign up for E-News!

Board Meeting Notifications

Event Notifications

CWB Website

Home
About Us
Contact
Board Meetings
Annual Reports
Library
Privacy
Terms

Targets

CWB Targets

Water Quality
Estuarine Health
Salmon Sustainability
Water Use
Watershed Connections
Water Supply
Riparian Area Protection

Cowichan Watershed

Cowichan Lake
Quamichan & Somenos Lakes
Cowichan Estuary
The Weir
Koksilah

Logo Email

[email protected]

Mailing Address
4335 Riverside Road
Duncan, BC, V9L 6M8

Copyright © 2025 Cowichan Watershed Board - All Rights Reserved. | Design by MAC5 | Site Maintenance by Web321

cowichan tribes logo cvrd logo polis logo refbc logo pacific salmon logo

The Cowichan Watershed Board (CWB) gratefully acknowledges the financial support of the above organizations.