Are floods threat to sac valley salmon?

[JDHunterJR]

Seems to me, that given how late the salmon came in this year, all the salmon redds with eggs would be destroyed by these floods. And I wonder how fresh salmon that are trying to build redds now can withstand these waters?

[Darian]

Kinda makes ya wonder at the reslience of anadromous fish.... Before the advent of hatcheries, these fish withstood all types of conditions (drought/floods, etc.) and still thrived....

The only things they can't seem to handle is loss of habitat and water.

[Rick J]

Previous floods before we screwed things up would inundate large overbank areas and the amount of sediment being washed out of the upper watersheds was much less. Now rivers are channelized with dikes greatly increasing channel velocities that cause increased erosion. Logging and excessive grazing hurts the upper watersheds causing much more sediment runoff that silts in spawning gravel and covers redds - pretty sad state of affairs what we have done to mother nauture in a few short years

[Covelo]

Floods have always destroyed fish runs. This is most obvious with species on 2 year cycles like sockeye where some rivers have poor runs every other year due to a natural disaster. People tend to expect quick responses where nature works slowly. We don't have the patience to wait a century or more for a population to recover following a natural disaster. Then again, it is debateble whether populations would recover without intervention considering how mankind has modified the system.

[slimfishin's]

That's a good point about a salmon run getting wiped out by floods etc... but I think you meant pink salmon. Anyway, most salmon runs are pretty flexible in the total life years it takes - like big adults that come back at age 5 instead of 4, and all those jacks and jills that come back a couple years early. Thanks to those fish, and fish that stray into non-natal streams, salmon can recolonize streams that have experienced a disaster.

When looking at disasters in the context of salmon/steelhead runs, one has to remember that these fish have adapted to these natural occurences. In fact, in intact systems, fish production often increases a few years after a disaster like a flood, landslide, or fire. Natural disasters often introduce all sorts of new ingredients to make the current habitat better. A land slide or flood will often introduce new spawning gravels and woody debris, that after some time in the system, will create all sorts of new habitat, often better than the pre-distrubance conditions. The idea is that across several watersheds, there are old habitats being reset, new habitats being created... so that there is this "patch dynamic" system of habitat conditions across the landscape.

Granted, we are talking about intact systems, where river and land processes are naturally linked. After all the mining, logging, and roads etc... these processes are obviously affected. In our valley streams, dams are the biggest problem, so a lot of the habitat incredients that might be introduced like new gravels and woody debris may not be there. Instead, you could have some major scour without the added benefit of such disturbances. That's not to say that the salmon populations in the valley will get wiped out after a major flow, since salmon often dig there redds pretty deep.

So I guess the scour would have to be pretty deep to mobilize all the eggs. My hydrology background isn't great, but I would guess that you would have some egg mortality, but I would doubt that this years run would be completely wiped out. In fact, the gravels may have gotten a nice flushing that they may have needed (like on the Feather). Although this year's return may have suffered a bit, conditions for next year's run may actually improve. It's really tough to tell!

All I know is it doesn't look like we'll be fishing until July!