Discussion in 'Steelhead' started by Cole L, Apr 20, 2014.
Not sure if this has been posted before but I learned a little. Thought I should share:
Thanks for posting this, Cole....I learned a little, too.
Might want to take some of the "info" with a grain of salt.
Great INFO! Here is another video from Jim Adams, who has a PhD in Fisheries from the University of Washington and backs much of what Bill says.
Its really hard for me to believe some of the info in this - the 10 to 12 inch mature hatchery fish mating with wild Skagit hens, out competing Skagit bucks and those fishing be able to survive in the river for a year (after all they are dumb hatchery fish that don't even know how to stay away from predator, how the hell are they going to grow up in the Cascade Hatchery pen and "know" all this)
The real issue with me on this video is the Ocean Conditions - we had in 09 2500 wild fish back and last year 8700 wild fish back - to my knowledge since 2006 the state has released about 250,000 (down from 500,000) hatchery smolts - if ocean conditions were't the major factor - we would see a more consistent trend.
There was an OPB special done awhile back that showed underwater cameras and these small fish trying to mate with the larger fish. It does happen. It is actually where Bruce Berry got his idea for his Rambulance fly. Check it out...
the "sneaker" fish phenomenon is why it is so important to protect wild resident rainbows in our anadramous reaches. they provide much needed genetics, and if a hatchery fish is fully mature when released in april it doesn't need a full year to survive to spawn with native hens. i don't know what the residualization rate is on the skagit, but i know on the coast it can be over 10% (don't recall exact numbers off the top of my head). With a 250k plant, that's up to 25k fish staying in the river and competing with native smolts (which are smaller and behave differently) and a % of those fish can be ready to spawn which reduces the productivity of the wild run.
our knowledge of the perils of hatchery fish is in it's infancy and my fear is that we will learn much more damning stuff as the years go on.
TallFlyGuy/Chris B -
The sneaker spawning by wild resident rainbows is an excellent example of the interaction between two different life histories of the same species. It has been argued for decades that have diverse life histories in the spawning population could be an important factor in population stability during periods of low survival of one of those life histories.
However lets talk about the issue of the sexually mature residuals from smolt releases. Spawn timing is one of the many populations traits/characteristics that are genetically controlled. This means that the offspring (in this case the smolts released) will have the same spawn timing. For the Chambers Creek hatchery fish in the Puget Sound region that spawn timing is December and January. The WDFW protocol for release of hatchery steelhead targets the early/mid-May as release dates. This means the smolts are being released more than 3 months after their parents had spawned. This of course means that any potential mature "smolts" would no longer be active/viable spawners at the time of release. Those fish would not represent any genetic threat to the wild population unless they were to survive to the next spawning season and even then the temporal overlap between the hatchery and wild spawning timing is limited.
Additionally finding mature males in Chambers Creek pre-smolts/smolts is very common and it would be expected the most of the released smolts that did residtualize would not be mature. However that is not always the case with other brood stocks; especially wild brood stock programs. Not only do such programs tend to have more early maturing males the spawning timing of those mature "residuals" would be the same as their parents - that is the same as the wild population.
If 10% residualize, and then whatever percent of that survive until the next spawning cycle, that puts allot of possibly sexually mature smoltz in the river for the following year with adult fish. Don't you find it interesting, the biologists pick one spot, and it just happens to be filled with "sneaker" fish? What if they pick 20 or 30 redds and put cameras in the water...Are we going to find the same thing happening with hatchery smoltz?
Unable to get the video to play but based on the text I assuming that the resident trout/steelhead interactions are wild fish; so much sure other than showing that there is the potential for "sneaker" spawning with mature residualized smolts the relevance of the video is.
Not exactly sure what your question is but maybe this will help. First the vast majority of the released smolts that residualize will not be sexually mature. The most will mature like their parents at age 3. For those fish to interact on the spawning grounds they would have to survive in the river for nearly 2 additional years. It has been known for more than 50 years that the survival of catchable size rainbows from domestic stocks is low. They experience high short term mortality which tends to elevate over the winter. One would expect that short term mortality to be even higher for those steelhead smolts. The reason is they are released in the spring during the peak of the spring run-off rather than at mid-summer low flows come for stream catchable releases.
Bottom line given the vast majority of the smolts that residualize would have to survive in the river for two years with a much smaller percentage needing to survival for a year. Best question it would be very unlikely than more than a small fraction of 1% of the smolts that failed to migrate would survive to be potential spawners. Of those that do manage because of the temporal separation between the hatchery and wild spawning periods only a small portion of the would have any chance to interacting with a wild fish.
In short a non-issue.
This is the abstract for a recent article that some might find of interest =
The Idaho Department of Fish and Game has proactively dealt with the potential adverse genetic effects of stocking catchable-sized hatchery trout in waters that support native salmonids by adopting a policy in 2001 whereby only sterile rainbow trout Oncorhynchus mykiss are stocked in flowing waters; however, concerns regarding the competitive effects of introducing hatchery trout into streams and rivers supporting wild trout have not been addressed. We stocked fish in the middle 3 years of a 5-year study to assess whether stocking hatchery rainbow trout of catchable size (hereafter, catchables) reduced the abundance, survival, growth, or recruitment of wild rainbow trout in streams. Catchables averaging 249 mm total length (TL) were stocked from 2006 to 2008 at an annual density of 4.2 fish/100 m2 into 12 treatment reaches of stream that were paired with control reaches at least 3 km apart in the same stream in which no stocking occurred. Wild rainbow trout abundance (including all fish ≥75 mm TL), recruitment, survival, and growth were determined from population estimates and recaptures of fish tagged with passive integrated transponder (PIT) tags during mark–recapture electrofishing sampling. The abundance of wild rainbow trout averaged 13.2 fish/100 m2 but varied substantially across sites and years, ranging from a low of 0.5 to a high of 131.3 fish/100 m2; similar variability was observed in recruitment to age 1. Estimates of total annual survival averaged 0.53 based on the population abundance estimates (which allowed for emigration and immigration) and 0.26 based on the PIT-tag recaptures (which allowed for emigration but not immigration). Our paired study design demonstrated that the abundance, survival, growth, and recruitment to age 1 of wild rainbow trout were all unaffected by stocking catchables. The lack of population-level effects from stocking catchables was not surprising considering the high short-term mortality and the socially and physiologically naive behavior typically exhibited by hatchery catchables stocked in lotic systems.
It is from the Transactions of the American Fisheries Society, 2012.
It is titled "Effects of stocking catchable size hatchery rainbow Trout on Wild Rainbow Trout Abundance, Survival, Growth and Recruit" by Meyer, High & Elle
Other than immediately downstream of the hatchery the density of residualize smolts on say the Skagit would be below that 4.2 per 100 square meter threshold in the above study. In short other than a very localized impact it is until that the hatchery smolts would have a significant genetic impact on the wild steelhead population or affecting the abundance, survival, growth or recruitment of the wild population.
Smalma, I continue to be supremely impressed with how well you logically explain information on this forum despite peoples attempts to bait and challenge you into some form of a pissing match. I guess your actual back ground and understanding of these issues, allows you to not fall back on emotion to try to "win" a discussion. Thanks again!
Looking forward to fishing with you.
The residualization rate is somewhat of a guessing game. As high as 17% but on average 5.6%.
http://www.researchgate.net/publica...eelhead_A_Meta-Analysis_of_Hatchery_PracticesThe following study documented resident hatchery fish mating with an adult steelhead.
Our sampling of anadromous adults was much more thoroughthan our sampling of residents, as we did not attempt toconduct sampling of the entire stream. Of the 2,207 juvenilesmatched to a single parent, 93% had known mothers and only7% had known fathers. Of the 237 adults matched to a singleparent, 86% had known mothers and 14% had known fathers.The overall sex ratio of female to male anadromous adults in thesystem was approximately 1.2–1, so the skewed results of uncollectedfemales to uncollected males is clearly not a reflectionof the sex ratio. These results are consistent with matings involvinganadromous females with “sneaker” resident males, asdocumented in other systems (e.g., Seamons et al. 2004; Arakiet al. 2007c)...........Despite including 300 residents (collected from 2001 to2004) as potential parents in our study,wewere able to documentonly 15 matings involving resident parents (11 for the adult-tojuveniledata and 4 for the adult-to-adult data). Of those 15matings, however, only one involved a hatchery resident (residualizedhatchery fish). Three of the 15 matings involved naturalanadromous females, 7 involved hatchery females, and the remaining5 matings were single-parent matings with residentfish; presumably the uncollected parent in these matings wasalso a resident fish.........It also demonstrated,however, that hatchery and natural fish interbreed widely in the study population. Despite the higher reproductive success for natural individuals, hatchery fish outnumbered natural ones by more than five to one, yielding an overall hatchery contributionto our offspring sample that was nearly twice that of natural fishhttp://www.cfr.msstate.edu/students/Wfpages/wfd/wf8273/bernson et al reproductive success of hatcher steelhead.pdf
The very low number of "known" fathers from the sample collected suggests that a high degree of "unknown" or sneaker fish are to blame.
Another study here that is often cited for "sneaker" fish spawning with steelhead.
McMillan, J.R., Katz, S.L., and Pess, G.R. 2007. Observational evidence of spatial andtemporal structure in a sympatric anadromous (winter steelhead) and residentrainbow trout mating system on the Olympic Peninsula, Washington.Transactions of the American Fisheries Society 136: 736 - 748.There are probably more, I just have not taken more time to research and study it out. In any event, Residualiztion and spawning from hatchery fish does in fact take place and therefore should be held as another risk hatchery fish pose on our wild fish populations.
Great discussion guys, thank you! I love to see two well read people comparing notes based on science. I much prefer that to the hurling insults and baseless misinformation at each other, which seems to happen more often than most of us would like around here...
Thanks to the links to those interesting articles; they supplied some "light" reading while I enjoyed my morning coffee!
The range in rates of residualism sounds about right. While the average maybe 5.6% I suggest that if are going to discuss numbers we use a higher value; the 10% you used early in this thread sounds about right. Using that higher rate would be consistent with WDFW's long time strategy of when there are not specific system data available that values be selected to insure possible errors would be in favor of the wild resource.
I agree that many folks have not recognized the importance and frequency that resident rainbows may contribute to the production of wild steelhead smolts. It is even less frequently recognized how important that behavior maybe under some survival conditions (such as the current low marine survival for smolts). AS interesting as that behavior and its implications are the issue as raised by the McMillian video is the role that residualized hatchery smolts might play in hatchery/wild interactions.
I thought that paper you provided documentation of resident hatchery fish spawning with an adult steelhead to be a well done paper.
As I under stand it the work was done on Little Sheep Creek on the Grande Rhonde system. When it comes to the potential of hatchery/wild interactions the situation on Little Sheep Creek and the Skagit are at opposite ends of the spectrum. Some of the reasons I believe that to be the case is --
1) The hatchery program on the Little Sheep is an integrated program with near complete over lap in spawn timing of the hatchery and wild fish while in the Skagit the hatchery program is segregated with nearly complete separation in spawn timing between the wild and hatchery programs.
2) The ratio of wild fish to the hatchery fish on the Skagit is much larger than on Little Sheep.
3) At the time of smolt release the environmental conditions are very different on the two systems. On the Skagit the smolts are release in the spring at the onset of a two month period of very high snow melt run-off (in fact the highest daily average flows occur during that period) while on little Sheep because of irrigation needs there is virtually no run-off. In the case of the Skagit one would think that mal-adapted hatchery residuals would have a much more difficult time resisting being flushed downstream then when compared to the situation on the Little Sheep.
The following quote from the Resident-anadromous interaction part of the discussion section of the paper may be the most relevant to this discussion and the potential impacts of the hatchery residuals spawning with wild fish.
"The large number of juveniles in our study not attributed
to any of the sampled parents were probably the offspring of
residents, and our results suggest that residualized hatchery fish
do not contribute in significant numbers."