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