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[frenchy]

I read this paper this week end:

"Reproductive success of captive-bred steelhead trout in the wild: Evaluation of three hatchery programs in the Hood River"
Araki et al. Conservation biology. In press.

It was a pretty interesting reading with a lot of data. The authors showed that offspring steelheads from a supplementary program (like in the Vedder, wild  fish spawn in a hatchery, offspring are raised in a hatchery and released) have a reproductive success indistinguishable from that of wild fish. In contrast, fish from a traditional hatchery (nonlocal origin, multiple generations in hatcheries) breeding in the same river showed significantly lower fitness than wild fish. Additionally, crosses between wild fish and supplementation fish were as reproductively successful as those between wild parents.

If anybody is interested, I can speak more about the study or give a link to the paper.

One result really surprised me. The authors said they sampled almost all the parents (98.4%) and returning offspring (96.7%) of the system. However, using DNA markers, they identify both parents for only 35.2% of the offspring, the mother only for 30.9% of the offspring, the father only for 10.8% offspring and none of the parents for 23.1% of the offspring. The authors explained these low numbers by saying that steelheads probably mate with resident rainbows in the wild. Does anybody know how frequent are these rainbow/steelhead crosses? What is a steelhead exactly? A rainbow with one allele saying: ”go to the sea”? or does any rainbow placed in the sea become a steelhead? I see another explanation for the low percentage of parental assignment: Steelhead coming back in the wrong river. Is there any data showing how often steelheads are mistaken in the river they choose to spawn? 

If anybody has any info, it would be greatly appreciated.

[Sam Salmon]

I've read that some Rainbows can go to sea and that some Steelhead will habituate in rivers-for no known reason.

Also I and many of my friends have caught hatchery fish in the Gold-a river with no stocking-so they do wander.

[Ribwart]

I am interested in that link Frenchy...

[frenchy]

E-mail sent

So nobody has any info 

[BwiBwi]

Might make a good thesis topic Frenchy.

[BwiBwi]

This is found in papers written by Dr. Craig Fusaro.
"The alternation between stream and ocean habitats for all anadromous fish is related to growth rate, food availability and relative predation rates in freshwater and marine environments. The ocean is a food-rich habitat compared to a stream, and once in the ocean, steelhead grow much more rapidly than their resident-type cousins that don't run to the ocean; freshwater streams provide a relatively protected habitat for young steelhead. A large body size is directly related to how many eggs can be produced by an individual fish. Since juvenile mortality is over 80 or 90 percent, a lot of eggs are necessary to contribute as many genes as possible to the next generation of steelhead.

Once the yearling fish gets the urge to return to the sea, it undergoes a process called "smoltification" during which physiological changes happen that allow the freshwater fish to deal with the saltiness of ocean waters. When the smolt is ready, it begins the long swim downstream to a coastal lagoon, where fresh and salt water mix. Some biologists think that coastal lagoons are more important to Southern Steelhead than they are to northern steelhead populations due the relative scarcity of water in southern creeks. As a result, Southern Steelhead may spend more time in lagoons than their cousins to the north. Since lagoon environments are rich in food, this helps the smolt to grow quickly, increasing its chances of survival in the ocean. After some time accommodating to salt and growing in the lagoon, the young steelhead enters the sea, where it will spend a year or two growing large quickly, maturing into an adult steelhead.

Once again this fish gets an urge; this time it's a call to return to freshwater, often, but not always, to the same stream in which it emerged from the gravel. It will meet up with a member of the opposite sex and spawn. A female Southern Steelhead, accompanied by a male, will begin to beat her tail against the gravel streambed, digging out a shallow pit called a "redd," in which she will deposit her eggs. When the redd is deep enough, she deposits eggs while the male fertilizes them. She then moves quickly upstream a bit and vigorously digs again, causing gravel to cover the eggs downstream. This process is repeated for days to weeks, and several different males may be involved in fertilizing the same redd over that time period. Having spawned, the adults then typically return to the ocean, unlike other salmonids, that usually die after spawning. A small percentage of adult steelhead may become trapped in low flow conditions in streams or elect to over-summer in the streams, and can survive given proper conditions until the next winter rains provide an opportunity for movement. Although the percentage of return spawners is typically low for any given stream, steelhead can return to freshwater more than once to spawn, and can live up to 8 years. "


(Higgins 1991) Suggested that southern steelhead commonly stray from their natal streams. Straying, if it actually occurs at significant levels in southern steelhead, may be selectively advantageous because it would allow spawners to opportunistically utilize more favorable streams when their natal streams dried up or were blocked by sand berms. An additional feature of southern steelhead is that they "miraculously" reappeared in large spawning runs when flows became suitable in streams that had been dry or otherwise inaccessible during the previous one or more years. The implication is that the fish, finding their natal stream unavailable during a given year, return the following year(s) until access can be gained.

[frenchy]

Oh, I am already done with the thesis

[BwiBwi]

Oh ya Frenchy you might want to read this file.

http://www.psmfc.org/meetings/steelhead/Ninth/2004%20NINTHSteelheadMgmtMtgSummary.pdf

[Sterling C]

Frenchy, I reccomend you talk with Scott K on fishbc. He along with several others on that site are very knoweldgeable and will be able to steer you towards some good info.

[frenchy]

Thanks,
I also found two more articles.

The first one has nothing to do with my firsts questions but it may interest some people... It is about the impact of catch and release on the Vedder and I see that Chris is thanked at the end of the manuscript.

Behavior and Survival of Wild and Hatchery-Origin Winter
Steelhead Spawners Caught and Released in a
Recreational Fishery
T. C. NELSON et al.
North American Journal of Fisheries Management 25:931–943, 2005

Abstract.—Mandatory catch and release of wild fish and supplementation with hatchery-reared
fish are commonly used to sustain sport fisheries on low-abundance populations of wild steelhead.
However, their effectiveness in limiting angling mortality on wild fish is uncertain. We radiotagged
226 (125 wild, 101 hatchery) angled adult steelhead Oncorhynchus mykiss near the mouth
of the Vedder2Chilliwack River, British Columbia, in 1999 and 2000 and monitored their subsequent
movements to determine survival to spawning and overlap in the distributions of inferred
holding sites, spawning sites, and spawning times. The distributions of prespawning holding sites
did not differ between wild and hatchery fish in either year, but spawning locations differed.
Holding and spawning sites used by hatchery fish were restricted to the lower two-thirds of the
river, downstream of the hatchery where they were reared but well upstream of their smolt release
site. Wild fish spawned throughout the watershed. Spawning times did not differ between wild
and hatchery fish, but varied with run timing. The maximum mortality from the initial catch and
release and radio-tagging was 1.4% in 1999 and 5.8% in 2000; true mortality rates were lower
because tag regurgitation was indistinguishable from death. The fishery subsequently killed 2.5%
of tagged wild fish and harvested 20% (1999) and 43% (2000) of the hatchery fish. Seventy-two
tagged fish were recaptured and released in the sport fishery up to three times without any mortality
before spawning. Hatchery fish were recaptured at twice the rate of wild fish. At least 92% of
unharvested fish spawned, and 75% of successful spawners survived to emigrate from the watershed.
The incidence of postspawning death did not vary with the frequency of capture and release.
Catch-and-release angling imposed small costs in terms of survival; however, behavioral differences
existed between adult wild fish and the adult F1 progeny of wild fish reared to smolt stage
in a hatchery.

The second one seems to indicate that there are a lot of crosses between resident rainbow and steelheads, but I am not completely convinced by this one

Evidence of partial anadromy and resident-form dispersal bias on a fine scale
in populations of Oncorhynchus mykiss
Jeffrey B. Olsen et al.
Conservation Genetics (2006) 7:613–619

Abstract
We examine sympatric anadromous (steelhead) and nonanadromous (resident) rainbow trout
(Oncorhynchus mykiss) from neighboring locations to test three hypotheses: (1) the sympatric life history
types are not genetically different; (2) fine-scale dispersal is the same for both sexes, and (3) fine-scale
dispersal is the same for steelhead and resident individuals. Data from 13 microsatellite loci reveal no
genetic difference between sympatric steelhead and resident O. mykiss but moderate population structure
(FST=0.019–0.028) between adjacent samples, regardless of life history type. Our results provide further
evidence of partial anadromy and suggest that geographic proximity and genetic history, more than
migratory type, should be considered when identifying populations for use in restoration of local genetic
diversity. We find evidence of resident-form dispersal bias on a fine spatial scale, however, we find no
evidence that fine-scale dispersal varies by gender. Conservation strategies should aim to maintain resident
and anadromous forms when they occur in sympatry, as they may be important in facilitating gene flow on
small and large spatial scales, respectively.

ps: It is crazy, the more I write in English, the more I feel like I do a lot of mistakes 

[frenchy]

I already had my own nation before...  . I am from France.

I know that there are a lot of debates related to hatchery/wild, but this specific study is pretty close to what I do and they seem to have done a pretty good job.

[BigFisher]

The fishery subsequently killed 2.5% of tagged wild fish and harvested 20% (1999) and 43% (2000) of the hatchery fish

wow 43 % shows how popular the Vedder is. Bunch of of other interesting survival rates.