Chinook/Coho Hybrid in the Cowichan

Dogbreath

Well-Known Member
https://www.cbc.ca/news/canada/brit...d-by-scientists-on-vancouver-island-1.5318092An odd looking animal for sure


Hybrid salmon discovered by scientists on Vancouver Island


Fish found in Cowichan River have genes of both coho and chinook salmon
CBC News · Posted: Oct 12, 2019 8:00 AM PT

hybrid-coho-chinook.JPG

Second-generation hybrid salmon, with genes from both coho and chinook salmon, have an uneven scale arrangement that researchers say is an abnormality associated with hybrid fish.
Two salmon researchers say a surprising discovery has been made on Vancouver Island.

Andres Araujo, a biologist at the Department of Fisheries and Oceans, and Will Duguid, a PhD biology student at the University of Victoria, recently found fish in the Cowichan River, north of Victoria, B.C., that have the genes of both coho and chinook salmon.

Tissue samples revealed the fish are second-generation hybrids, meaning they are the spawn of hybrids.

The hybrid fish, according to Araujo and Duguid, are a rare find in Canada and are likely the result of drought in the Cowichan watershed, which has impacted when and where coho and chinook spawn.

"For a hybrid to exist we need overlapping spawning grounds and timing," said Araujo, noting that chinook usually spawn in September and October, whereas coho traditionally spawn toward the end of October until December. He said when summer droughts extend into fall it can push chinook spawning season back into when coho are also starting to spawn.


cowichan-river-researchers.jpg

Will Duguid, left, and Andres Araujo say drought likely caused coho and chinook spawning seasons to overlap.

Duguid said there are some fish that routinely generate hybrids — such as rainbow trout and cutthroat trout — but not wild salmon.

"Apparently, it rarely occurred in the past and there has never been documentation of hybridization into the second generation," said Duguid.

He said a member of the Cowichan Tribes spotted the first hybrid in the river during an adult fish tagging study being done in partnership between the First Nation and the province.

Duguid said the hybrid fish can sometimes be identified by their abnormal scale arrangement, which is not patterned evenly on either side of their lateral line.

"This is indicative of the fact there may be other abnormalities that we can't see," said Duguid.

He said the hybrids are also identifiable by the degree of spotting on their tails, the shape of their anal fins and the morphology and colouration of their mouths.


coho-chinook-hybrid.JPG

A member of the Cowichan Tribes spotted the first adult hybrid, similar to the one shown here, while tagging fish for conservation purposes.

The duo said human activity, such as forestry practices and climate change, are also changing the landscape of the Cowichan River region and also likely played a role in causing the hybridization.


"You are seeing a biological response to potentially an anthropogenic, or human-caused, forcing," said Duguid.

Araujo said it is too soon to know if the chinook-coho hybrids are part of an evolutionary process. The hybrid fish have not yet been named.
 
"Duguid said there are some fish that routinely generate hybrids — such as rainbow trout and cutthroat trout — but not wild salmon." Not true. Happens infrequently - but does happen - not only between Chinook & coho - but also between pinks and chums. The 2nd generation hybrids - the spawn of hybrids is the rarer situation and likely this is the 1st proved thru genetics.
 
the first thing that popped into my mind in about four years time, all the snarky comments when someone catches one of these and posts it on SFBC
 
An interesting system the Cowichan it's the only place I've heard about a Masu Salmon from the other side of the Pacific showing up and then of course there's the occasional Brown Trout lurking around after all these years.
 
More than just the occasional Brown Trout actually.They're mostly in the upper reaches and very prevailant in the fly fishing only section of the river,some going 10 + lbs.You get them on the lower section where I fish most occasionally though.Got one last year while twitching jigs for coho that was 2.5-3 lbs.You can't keep them though,because all wild trout must be released in the Cowie which is esentially all of them because there's no hatchery enhancement on the river.
Interesting that a Cherry Salmon was caught in there.That fishes "GPS" system was majorly f**cked up!lol
 
"Duguid said there are some fish that routinely generate hybrids — such as rainbow trout and cutthroat trout — but not wild salmon." Not true. Happens infrequently - but does happen - not only between Chinook & coho - but also between pinks and chums. The 2nd generation hybrids - the spawn of hybrids is the rarer situation and likely this is the 1st proved thru genetics.


Interesting about the pink/chum hybrid. I would have guessed they didn’t overlap in timing but I don’t know much about that. Probably no hybrid vigor in any of these combinations or we’d have seen hatcheries producing them at one point.

To be picky,‘infrequently’ is similar to ‘don’t routinely’ so your statement is the same as his quote and you are agreeing with him that wild salmon don’t routinely generate hybrids, no?
 
Something like 5-15 hybrids out of ~30,000 is what I mean by ‘don’t routinely" as far as pinks & chums. But chum likely have like ~2000-4000 eggs per female - so those numbers sound low until one looks @ potential for hybridization.

I suspect the coho/Chinook hybrid numbers could even be somewhat higher than that - esp as juvies - as there is a spectrum (verses discreet) of indicator metrics that show speciation between coho & Chinook (eg the white bar on the "sickle-shaped" anal fin, etc).

I also think there are overlaps in time/space in spawning only in certain areas in certain watersheds where species can hybridize and likely only for some run timing and not others. The "early" run of chum w pinks on the lower end of a watershed, for example, and the fall run of Chinook w coho.

I can't say I know of or have seen any 2nd generation hybrids - the spawn of the hybrids. One would need to send those away for DNA analysis to tell, tho.

Trout seem to hybridize much more frequently - esp. rainbows and cutties...
 
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We seined a sockeye with steelhead spots on the tail once, back when there were steelhead and sockeye in the early 80's.
 
I heard chin ho's were raised at rosewall creek hatchery many years ago.wonder if this duo have those reports on hand.
 
This article was based on the radio interview and contains quite a few inaccuracies. The novelty of what we are seeing is both the first documented case of F2+ hybrids produced in nature (i.e. cross of a Chinook and a Hybrid) and the relatively high rate of occurrence in the Cowichan Area. For example during juvenile sampling work in the southern gulf islands in 2015 12/372 "Chinook" we handled turned out to be hybrids (3%). Very few hybrids have been found in samples from areas outside of where Cowichan fish are prevalent.
 
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