Hatchery iFish Opinion...........

[Ty]

I am curious to the "real" opinions of the iFish community on Hatchery fish.

[garyk]

Interesting poll, however, you might give some thought to clarifying the questions. Such as #1, regarding 'successful' hatchery/wild spawning.

Hatchery/wild introgression has been well documented, so yes they do 'successfully' spawn. The unsuccessful part comes from the lower survivability of the resulting progeny. That is what's really important.

Question3 "Do you fish for hatchery fish"? ... is hard to answer because if you participate in virtually any anadromous fishery, you have a chance of catching hatchery-origin fish. Maybe you're asking - "do you specifically target certain hatchery origin runs"??

[ 03-27-2003, 01:37 PM: Message edited by: garyk ]

[Ty]

It is not well documented that hatchery fish successfully spawn in the wild, especially with wild fish. It is well documented that their behavior is not aggressive enough to compete with wild fish and even considered appropriate spawning behavior if you will, i.e. males not aggressive enough to defend spawning female, female not aggressive enough to gaurd reds.

Wild fish may not even be able to reconize hatchery spawning behavior to successfully interbred, and there are many spacial time differences between run time that may seperate them. [img]graemlins/stupid.gif[/img]

[garyk]

I guess the question turns on the word "well" as in "well documented". Or how much evidence is needed for something to be well-documented.

There's certainly a lot of papers on the topic and if you're seriously interested I think I can provide references.

Also the documentation varies with the salmonid species.

For example, genetic introgression between wild and hatchery-orgin rainbow trout on the Metolius River was conclusively proven.

Perhaps though you're only interested in certain salmonid species or stocks?

[Ty]

I should have clearified my questions. I would agree that hatchery anadromous fish "spawn" in the wild and that has been documented. The succes of their prodogeny is very poor if at all in most cases and if they actually spawn with wild fish has not been proven. Any influence on wild stocks and or actual genetic flow from one to the other has not been documented on anadromous wild stocks.

Obviously, steelhead are in a catagory of their own and hatchery fish should be treated on a stock by stock basis and not lumped under one some and assumumed that if observations create conclutions for all stocks on a whole.

It is hard for me to understand all of the bacshing of hatcheries when 90% plus of the readers in this column fish for hatchery, yet are quick to be critical w/ out offering solutions to the problem.

Hatcheries are a intergral part of the management of anadromous stocks in the NW. Unfortunatly they offer no sustainable solutions to depleted and destroyed stocks.

I am just challenging the everyday fisherman of the NW to help come up with creative solutions to comprehensive problems that areconstantly changing and evolving with changes in the enviroment. :whazzup:

[GutshotApe]

Originally posted by garyk:
Hatchery/wild introgression has been well documented, so yes they do 'successfully' spawn. The unsuccessful part comes from the lower survivability of the resulting progeny. That is what's really important.

<font size="2" face="verdana,arial,helvetica">garyk is right...a hatchery fish will spawn...together with another hatchery fish or with a wild fish. The offspring from either type of union do not survive at rates high enough to replace the parent generation....but they compete with, displace, and otherwise cause negative interactions with wild x wild juveniles. Wild x wild spawning produce the only offspring that year in, year out, are capable of surviving to replace their parents.

If this is incorrect, then why don't we have strong, healthy naturally-spawning salmon & steelhead runs in all the rivers with hatchery programs? :whazzup:

[Ty]

Good point Gut shot....... I have always been curious as to the legidimacly of documented wild x hatchery spawning interatcions. The same lien of thought beggs the question as to how suseptable anadromous stocks are to genetic drift (inbreeding). Even stocks such as the red fish lake sockeye have shown 98% heterozygosity even though there numbers have dwindled to enough to only be counted on one hand, suggesting that genetic variety in wild anadromous stocks are higher than that previously thought and genetic variation could be independent of population size. Even though, it is suggested that small population size is negativly influencing most of the depleted stocks of the NW.

[GutshotApe]

Genetic variation is independent of population size? How can that be? Not saying you're wrong...but it goes against everything I understand about genetics :whazzup: .

As for the Redfish Lake sockeye, I read in a paper by reliable scientific source that there was a complete blockage of the Salmon River caused by Sunbeam Dam...this lasted for 20 years or more in the early 20th century. The sockeye run that returns to the upper Salmon River and Redfish Lake must be composed of descendents of Redfish Lake kokanee because the anadramous run was killed off by the dam during the time it blocked the river.

[rob allen]

excellent poll and discussion

[Ty]

Well there is another paper on Redfish Lake sockeye / kokanee showing that is used as a text book example in genetics and evolution classes.
This paper show the phylo-genetic linages that seperate the kokanee and sockeye each into two distinctive genetic componets. There is the shore spawning kokanee and sockeye, and river spawning kakanee and sockeye. It was shown that the all four populations had common decent, but where not interbreeding for quite some time.

As for the lake blockage, it would be a safe assumption that the lake was repopulated by sockeye runs outside Red Fish Lake, not the resident kokanee.

The point with the smaller population that still has a 98% heterozygosity with a population below 100, shows that anadromous stocks may be able to sustain low number while still retaining high amount of genetic diversity, other wise causes of genetic drift would have left the population with greater than 50% homozygosity, suggesting imbreeding.

The conclutions from this research suggests that there is more flow between anadromous stocks than previously thought, therefore increasing genetic fitness within all stocks, showing gene flow from larger stocks straying into smaller stocks.

[GutshotApe]

Originally posted by Ty:
As for the lake blockage, it would be a safe assumption that the lake was repopulated by sockeye runs outside Red Fish Lake, not the resident kokanee.

<font size="2" face="verdana,arial,helvetica">Where else would the source be? The only other sockeye runs in the Columbia are in the Okanogan and Wenatchee Rivers. There were runs up the Wallowa River but they were killed off before the Sunbeam Dam era. Same for the sockeye run up the Deschutes into the Metolius. I read about the Sunbeam Dam in a paper by Dr. Robt. Behnke of Colorado State Univ. (and probably still have it around here somewhere) and his theory was that the Redfish Lk kokanee are the source of the remnant Snake River sockeye run...that a small percentage of kokanee often will exhibit anadromous behavior. A sockeye run on the South Santiam River developed from kokanee in GreenPeter Reservoir...there are other examples.

[ 03-27-2003, 09:13 PM: Message edited by: GutshotApe ]

[Crashin' Bait]

Originally posted by GutshotApe:

If this is incorrect, then why don't we have strong, healthy naturally-spawning salmon & steelhead runs in all the rivers with hatchery programs? :whazzup:

<font size="2" face="verdana,arial,helvetica">Can it be that the hatcheries were placed on river systems where watershed damage was extensive enough to affect fry survivability (ie - siltation, riparian damage, ect.)?

[Ty]

Gun shot the kokanee you are refering to that may have repopulated Red Fish Lake actually are a resident form of sockeye. It was determined that there wasn't flow between the kokanee and sockeye populations with in the lake. Of course kokanee have outmigrants that can return as the sea run adults. In this particular case it was determined that the there where four seperate populations, seperated by run timing and where they spawned in the lake and in the river. So... Yes, Sockeye that resided in the lake very well could have repopulated the anadromous form and there certainly could be mixing between the two.

The sockeye and the kokanee populations should not be confused in this case. The results of this study are very conclusive due to the advent of phlyogentics tracing specific genetic markers that can be asign linages and trace back time of di*****nce.