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[canucksfan233]

Anyone have any idea on how freshet impacts the run timing on fish?

I've heard that a later freshet will result with fish pushing into freshwater later due to not wanting to exert more energy to travel the same distance but also heard that a freshet later in the year will result with fish pushing in earlier due to there being more water and feeling "safe". I'm also thinking that it would not affect the run timing as a fish has a certain window to spawn along with the mindset of mating.

Heard that some tributaries around the lower mainland have received some coho already (outside of the Cap) due to there being higher water levels around this time of the year and the fish have been zipping up quickly.

[RalphH]

Commonly the term freshet refers to the spring time flood caused by snow melt. I really have no idea how prolonged or heavy freshet affects run timing. The high turbidity  of heavy freshet waters can actually be hazards to fish so may delay returns. Years of heavy or delayed and prolonged freshet can mean rivers will be in better shape (better levels and temperatures) for fishing in summer once the freshet tails off.

In the fall and winter we of course can get heavy rains that cause the water rise after the period of low water in the late summer and early fall. That will draw runs of fish into streams.

I'd be astonished if coho are showing up in local rivers that don't normally see those fish until late summer or early fall. Those fish would be giving up 2 or even 3 months of ocean growth and likely lack the fat to develop spawn or even live until they would normally spawn in 4 to 5 months.

[Roderick]

Run timing has a strong genetic component and is often driven by the length of the days (the photoperiod). Exceptionally high water will, of course, delay upstream migration, as does water that is too low, but this usually just affects where the fish hold and not the actual timing of the run. 

Chinook in particular are such powerful swimmers that even moderately high water is no hinderance.  It's the reason we call them "springs", because some runs start upriver during the freshet.  The runs that spawn way up at the top of the Fraser start entering the river in May and spawn at the time in the fall when the rain comes but before it freezes and the water drops. 

Coho have a much wider spawning period between October and January, and will often enter rivers long before they are ready to spawn.  For example, Cap coho that enter in May don't spawn until September or October.  That's 4 or 5 months.  There is an advantage to being first to the spawning grounds.  I wouldn't be too surprised to see the early component of the fall coho that are ready to dig redds in October entering in July if there is enough water. Certainly Vedder holds coho in early August. 

Chum and Pinks, on the other hand, seem to wail till the last minute to enter, and only live in the river for a short time before laying eggs. 

[coastangler]

For example, Cap coho that enter in May don't spawn until September or October.  That's 4 or 5 months.

Do you have any data around this? This may be a bit off-topic but my understanding is that the Cap coho run in May is introduced by humans and engineered so the fish return earlier than normal, resulting in a summer fishery in the Lower Mainland. I couldn't find written evidence of this but I was given this answer by a BC Fisheries employee a while back when I asked the obvious question (why only the Cap Coho return in May while the rest of Coho runs near the Lower Mainland return starting September). If you have any more info to share on the topic it will be appreciated as this is something I've always been curious about.

[hammer]

There are summer coho in a number of systems. There was a point when the Cap received Qualicum coho I believe. I also think the Seymour had some summer fish. I am not sure about the may/June fish but I want  to say they are from elsewhere.

[clarki]

It appears that early run Cap coho predate the construction of the Cleveland Dam and the hatchery

Source: https://publications.gc.ca/collections/collection_2014/mpo-dfo/Fs97-4-2118-eng.pdf

"The Capilano River and the nearby Seymour River support runs of unusually
early-returning coho. While most of the British Columbia coho stocks return late
in the fall, substantial numbers of Capi1ano adults start arriving in June or
early July. A few fish arrive earlier in the spring and the run extends as late
as December (E. T. Stone, Department· of Fisheries and Oceans, pers. comm., and DFO
Spawning Records). Fishery Officer spawning reports in the 1930s described two
Capilano River coho runs. The first was comprised of smaller fish (1-2 kg) which
returned in June and spawned in the upper reaches above the Second Canyon. The
second run was comprised of larger fish which returned in July or August and were
often delayed below the falls in the Canyon or below the water intake due to low
summer flows. "

[Roderick]

Thanks clarki, it's good to see some written info about this.  It confirms what I have always believed, that the hatchery just maintained the coho runs as closely as they could to what was there before the dam went in.  I do know they carefully separate out and spawn the early cohos that arrive in May to make sure the genes involved in the earliest run timing are preserved. 

I have heard that there also used to be a run of summer run red chinook that started in July, but the river is always a trickle at that time of year because of the dam and the run pretty much died out.  The white chinook, which spawn later, are definitely introduced. 

[coastangler]

Thanks all for the responses and the info! A follow-up question I have is related to the ability of Capilano anadromous fish to naturally spawn. I know there are small creeks and tributaries with small populations but aside from those, do the Cap support any kind of natural spawning or everything is hatchery driven? My understanding is that the dam will block the gravel but is common to see many salmon in "spawning mode" in the upper river pools during November/December. Always wondered if that will come to anything or the eggs will just get washed away.

Thanks

[Roderick]

There are very limited spawning areas below the dam.  It seems only the late fall coho and winter steelhead have any chance at all. 

[RalphH]

The Cap' and Seymour both support similar runs of fish - early arriving coho and summer steelhead. There are other such runs on the south coast. The White River (Salmon river watershed) on Vanisle reportedly has a spring early summer run of coho (and steelhead) as does the Kakweiken River that empties into Thompson sound on the south central mainland. Both rivers share proximate latitude. Generally all salmon runs tend to arrive earlier in their rivers moving from south to north.

[jim]

It used to be that the Cap Hatchery would take the salmon heads, complete with CWT (coded wire tag) from the angler, so I would drive up there and knock on the back door. I did this a number of times, then Eldon Stone the manager took me into his office and we chatted. I found out about his efforts to keep the early and late return fish separated from each other. Coho, of course.

[Fish Assassin]

They still take hatchery fish heads.

[Roderick]

There is at least one river near Tofino on WCVI that gets early coho.  The "bluebacks" show up in the ocean near by in June and stack up if the water is low.  I have no idea which river. 

[Every Day]

Summer run coho aren't actually all that rare. The more I explored on Vancouver island, the more we ran into them. They tend to appear on rivers that have substantial barriers, and behave the same as summer steelhead. For the most part, they enter in mid to late July, but I have caught them as early as mid June. Peak is typically August. They tend to be smaller fish, 4-6 pounds. I've now captured them on 6 different rivers (in numbers), and I'm sure there are others around that we don't know about yet/ still.

As for the original question, I personally believe that years like this year speed up migration on most rivers. I've been finding steelhead and summer run coho earlier, and much higher up than I have the past 5 years so far. On the rivers I fish on the island, it's likely due to low water being a migration hindrance most years. This year they have had the ability to move unimpeded. I also enjoy how it tends to spread fish out more. It matches my preference of hiking lots, and tends to make them less vulnerable to fishing in my experience.

[RalphH]

Here is a paper about the Capilano hatchery from 1983. It also provides some history on the salmon and steelhead runs prior to the operation of the Cleveland Dam. In 1951 the start of the coho run was recorded as starting June 25th on average. No mention of coho from the biq q but the chinook originally came from there.

https://waves-vagues.dfo-mpo.gc.ca/Library/349582.pdf

The Muchalat system  near Gold River is another Vancouver island stream that at in the past had an early coho run. Somewhere I have a 1960s era article by Ted Peck who claimed to have counted about 30 spawned out coho carcasses in a tributary of the lake in late June. In the same article he said he had once taken a silver bright Capilano doe 'heavy with roe' in late winter.

There are a couple of Upper Fraser Valley rivers that have small numbers of coho that start to return in mid-summer. Eric Carlisle also wrote about fishing both summer coho and steelhead on the Seymour River in the 2960s. By that time the fish populations in the river had been impacted by dam construction and logging among other issues.