Winter Springs – Cowichan River

Time moves on and the annual fishing calendar arrives at winter chinook saltwater trolling in November of each year. The best months are now until the end of February for five- to ten-pound feeder chinook in their second year. We fish mostly American chinook as they have put out many more fish than on the Canadian side of the watery border. And the nearing extinction level Fraser chinook are an example where DFO has responsibility but has allowed stocks to slide to dangerously low levels. They will have little effect on our fishery. 

On the other hand, some of our winter fish include Cowichan river stock as it has rebounded surprisingly well since it’s poor days in the late 2000s. Cowichan adults reached the depths of 900 in-river fish in 2009 before work was done to improve numbers. Last year the number was an unheard of 26,000, though a lot of jacks came back and the adult figure was 14,700. The jack number implies a good year in 2018, and to date the counting fence has received 12,000 chinook. The reason that some of our winter fish would now contain some Cowichans is that this special stock spends a year circling Strait of Georgia.

(And it might surprise you to know how many species call the Cowichan system home. See about half way down this page: http://www.cowichanwatershedboard.ca/tags/salmon).

After circling inside waters, meaning Strait of Georgia, the chinook migrate to the ocean. While most would likely take Johnstone Strait, some take Juan de Fuca Strait. I say this, having seen the stats on October commercial fishery stats for off Nootka Sound some years ago which found primarily Cowichan stocks. A good reason to shut that down for some years, but an indication of migration patterns, as chinook exiting Johnstone would likely continue north to Alaska, rather than turn south.

Some, though, pass through our area from Sidney to Port Renfrew. Note that in the north end of SOG there are area closures to protect Cowichan fish, even though these fish are now doing well. Sport fishers in these areas have learned to fish around the closed areas. Even so, the measure is intended to return 2,500 more adults. Do note that the five closures are not sitting well with anglers from Campbell River south. Three of these are: Lambert Channel Algerine Passage and Cape Mudge.

The exploitation rate of Cowichan Chinook from 2009 to 2014 is shown in the graphic below. You will note that the sport fishery, mostly SOG, has the largest impact, almost as large as escapement. The remaining commercial troll on WCVI (West Coast Van Isle), of 5%, has a small effect.

From: http://www.pacfish.ca/Cowichan/images/figure10.png.

Note that this graphic includes the worst year for Cowichan returns, 2009, and thus the percentages may well be distorted for this reason.

The Washington catch of 8% suggests that, yes, some Cowichan fish migrate and return through Juan de Fuca. Based on the north SOG closed areas, DFO must feel numbers are not high enough to be of concern. I recall from fishing Saanich Inlet for almost 15 years, starting in the late ‘70s, that deep in Finlayson Arm in September, and Bamberton, was an annual calendar fishery for Cowichan chinook. Tozier Rock and Mill Bay were good for coho on the surface in October, though earlier, they too, were deep in Finlayson. These staging grounds suggest Juan de Fuca as a migration route.

It may also be the case that we are now seeing some of the Sooke Basin netpen chinook from the South Vancouver Island Anglers Coalition. The first cohort would now be two years old, and thus may contribute, for the first year, this winter, likely from Constance Bank west.

As an aside here, while Cowichan chinook have improved, the habitat restoration work includes that Clay Bank project that cost $1.5M, showing how quickly money can get used up. See: http://www.pacfish.ca/Cowichan/ - figure10.

And this one has been done twice, because the bank collapsed after the first work was done.

For a list of projects to 2012, see: http://www.pacfish.ca/Cowichan/documents/habitat_restoration_activities.pdf. The images of Stoltz clay bank are worth a view, considering that we are looking to doing river restoration in a low flow climate change era for all our rivers.

In addition to the north SOG sport closures, commercial fishing has indeed been curtailed 50%, and the size closures in our area from March to July, as well as the August to October closure in the Gulf Islands all protect Cowichan chinook.

Work remaining on the Cowichan includes the following: 

The following key knowledge gaps were identified during the Critical Limiting Factors Expert reviews in 2013 and 2016:

• Lack of knowledge regarding the available food supply and rearing capacity in the Cowichan Estuary as well as identification of key and critical habitat to protect and restore for Chinook production
• Quantify the amount of aquatic rearing habitat that has been lost in the lower river over time
• Estimations of annual freshwater juvenile production on an annual basis for fall Chinook (egg to fry survival, fry to smolt survival and hatchery effectiveness) to determine how many wild and hatchery Chinook are currently entering the marine environment. This was also highlighted as an important action item and assessment tool in the 2005 Cowichan Recovery Plan (LGL 2005)
• Lack of information and focus on the spring Chinook run in the Cowichan River, including genetic distinctness, distribution in the watershed, current abundance key migration period and rebuilding potential
• Lack of information regarding the existing and potential use of the Koksilah River by Chinook
• Uncertainty of the density dependent effects of large hatchery releases of Chinook fry on the survival rates of wild raised Chinook fry
• Increase understanding of threats and limiting factors affecting juvenile survival in estuary and early marine habitats, especially in the Strait of Georgia and WCVI, and mitigate these factors where possible (link to Southern BC Chinook Strategic Planning Initiative)
• Uncertainty on the impacts of aquatic invasive plant species to fish access, cover rearing and passage, including invasive plants in riparian areas
• Some of the CLFs that affect fall run Chinook likely impact early run Chinook as much or even more: for example, low summer flows, woody debris, gravel, log jams, water temperature, etc.
• What flows are required to allow for appropriate sewage dilution
• 2014 and 2015 were very different years but there were still large numbers of fish in the bay. It would be useful to see how fish behave with each incremental drop in flows
• What accounts for the high level of in-river juvenile mortality as evidenced by the BCCF PIT tagging studies and DFO’s Rotary Screw Trap Studies

As above, this section of text comes from: http://www.pacfish.ca/Cowichan/. It was last updated in 2017, so is a recent document in many respects. Interesting stuff.