Mike B,

I think this is the technique used on the Kalama...

First, if you're not familiar with the river, there is a waterfall that blocks upstream migration. They put a plastic barrier on the waterfall, too, just to make sure that no fish could jump it.

All the fish that went beyond that waterfall were weighed, measured, named and numbered, DNA sampled, and released.

This included both wild and hatchery fish.

When the smolts came back down the river, they were collected in smolt traps. Not only could they tell if a particular smolt was wild/wild, hatchery/hatchery, or hatchery/wild, they could even tell that a particular smolt came from "Wild Hen #24" and "Hatchery Buck #16".

The smolt sampling done at this point showed that all three crosses had good egg to smolt survival.

When those smolts returned as adults, the only adults that came back were the wild/wild ones, statistically speaking.

I think that's pretty much it, in a nutshell.

The implications are as follows:

1. Wild fish always do it better, no matter how well we think we're doing it in the hatchery.

2. Hatchery fish can spawn in the wild, and can do it with wild fish. The problem with this is two fold. First, HxH crosses produce smolts that compete with the WxW smolts for food and space, but don't ever become adults. This is an unnecessary restriction on wild fish productivity. Second, not only do WxH crosses also do that same thing, they also remove a wild fish's genes from the gene pool for that year's run. If a hatchery fish spawns with a wild fish, that wild fish is as good as bonked...it's eggs or sperm almost never translate into an adult fish.

This doesn't just apply to Chambers Creek or Skamania hatchery fish...studies show that two fish taken out of the wild to produce broodstock program fish produce more smolts due to the hatchery protections, but return less adults than the two wild fish would have done if just left in the river.

Not only do they produce less fish, the ones they do produce are clipped hatchery fish that are harvested.

Again, it's the same as bonking two wild fish in order to gain a few (literally a few) hatchery fish for harvest.

Fish on...

Todd.