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[Rodney]

Release total for 2016 has been adjusted.

http://pacgis01.dfo-mpo.gc.ca/DocumentsForWebAccess/HatcheryReleaseReports/ReleaseReport.aspx?IDValue=107#Cohoreleased%20fromChilliwack%20R

[dnibbles]

Obviously budget cuts have forced decisions to be made as to where the $$$ are to be spent. How does the hatchery make decisions on production quotas for the various salmon species? Do they give the most $$$ to the most endangered specie relative to historical records?

Why less coho/chinook for more chum? I have noticed, notwithstanding last year which I saw lots of chum, that there have been far fewer chum in the C/V in recent years compared to the past.

I have it on reasonable authority that the decision to bring coho numbers down over the past few years at Chilliwack is not a direct tradeoff for maintaining chum production. All hatchery salmon production has specific goals they are trying to meet, whether they are to support terminal fisheries (Chilliwack coho), contribute to mixed marine fisheries (Chilliwack Chinook), or to rebuild or supplement depleted runs (Chilliwack chum). Obviously budgets are not getting any bigger for hatcheries, so decisions have to be made to try to achieve the best balance for the various user groups.

In the case of Chilliwack (and other South Coast) coho stocks, there were adjustments made in 2014 to production numbers at various hatcheries to try to better align production with the demands of the fisheries they service. IN recent years, the Chilliwack hatchery had had up to 40,000 coho swim back into the hatchery, with catches in the river only a percentage of that. The reduction intended to find a level of production that would bring enough adult coho back to the river to keep the sporties happy, while avoiding the expense of producing hundreds of thousands of surplus coho smolts (remember, they are reared at the hatchery for 1.5 years and are therefore very expensive to produce) that were contributing to the huge hatchery surpluses. These cost savings, while not specifically earmarked for chum production, would have been used to put towards maintaining other production priorities such as chum, Cultus sockeye, upper Fraser Chinook, etc.

Lower Fraser coho returns are driven almost exclusively by marine survival, the difference in return based on release numbers is usually lost in the noise. One hypothesised (but untestable) offshoot of reducing overall Southern coho production from hatcheries is a reduction in early marine competition between hatchery and wild fish, as well as simply between all the hatchery fish. Its possible that compensation could occur, seeing similar numbers of hatchery fish return from lower release numbers.

One other thing of note is that the hatchery is using some of the savings to initiate an experimental release of 100K coho salmon at a later and larger release size. If this strategy is successful in increasing survival rate, it may potentially be expanded.

It's easy to focus on release numbers with hatcheries, but the only really important number is the number of fish returning to be caught or to spawn.

nibs

[DanL]

Thanks for the insight, I could read posts like this all day long.

One other thing of note is that the hatchery is using some of the savings to initiate an experimental release of 100K coho salmon at a later and larger release size. If this strategy is successful in increasing survival rate, it may potentially be expanded.

I wonder what method they would use to identify return rates of later release coho vs regular release.

[Noahs Arc]

How are these older 100k smolts clipped?

[RainbowMan]

Great post. Thank you!

The reduction intended to find a level of production that would bring enough adult coho back to the river to keep the sporties happy, while avoiding the expense of producing hundreds of thousands of surplus coho smolts

Now if they could also modify the gene of those hatchery cohos to make them a bit more 'bite-friendly'.... 

[dnibbles]

They are adipose clipped just like all other releases. They have been separately genotyped so they can be identified via DNA sample upon return.

There is some evidence/information that suggests that juvenile coho that enter the Strait (or Puget Sound) at a large enough size may be more likely to reside on the inside vs moving outside. This could also have benefits for the (now almost obsolete) Georgia Strait summer coho fishery if it were to show promise.

You never know until you try. The SoG summer fishery is already non-existent, so not much to lose by trying some new approaches.

[Noahs Arc]

Thanks dnibbles, always a wealth of information!

[Tex]

Wow, terrific insight. Thank you, dnibbles!

[Tylsie]

Thanks you Dnibbles

40 Thousand! That is crazy! Even if sporties took half that leaves 20,000 Coho making it to the hatchery! I have seen hundreds, but never thousands, that would be a site to see. With the only say 400 pairs (800 fish total) required (average fecundity of 2400 to reach 900,000 to be released with 60,000 lost along the way) that leaves a whole lot of excess coho.

[sugartooth]

What I find interesting on the list of release totals is that only 8000 steelhead were released in 2013. Does anyone know if this is accurate or a misprint ?