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Posts: 32886
Location: Rhinelander, Wisconsin | Something happened to the thread we were using in the database. Page 7 is viewable in 'printer friendly' mode only, so I locked down the previous thread so no one thinks they are being deleted, and I'm continuing the conversation with a new thread.
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| Dave, a question or two below for you if you don't mind.
DAVE: The second method is much simpler. We simply analyze netting and creel survey data from lakes that are entirely dependent upon stocking, and if we see fish over 50" long, we know that potential exists. Lakes all over Wisconsin reflect this potential. These combined phenomena help to explain why Wisconsin biologists do not suspect broodstock genetics to be an important factor limiting the relative abundance of trophy-size muskellunge in this state today.
ERIC: What lakes are entirely dependent upon stocking in NW Wisc. that reflect this potential? I personally suspect that the large 50" fish that are ocasionally coming from lakes that were not created as new muskie lakes initially through stocking, that those 50" fish are not from our hatchery but are the result of a few remaining larger strain fish that were in these lakes all along that have somehow beaten all odds and by pure luck there are still a few that show up once in a while. I suspect that these fish over 50" ocasionally coming from these lakes are not stocked fish from our hatchery. I'm not talking mid-forty inch fish here, but legitimate fish over 50". Is this possible?
Thank you.
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Posts: 1291
Location: Hayward, Wisconsin | Dave:
If you will allow me, I would like to hopefully clear up several misunderstandings with regard to our Bone Lake brood stock and add some new information into the mix.
You stated: "We also believe the probability is VERY small that some minor stock mixing years ago resulted in a degree of outbreeding depression that could adversely affect ultimate size potential among the fish we are propagating today. The complex mathematics behind that proposition just doesn't add up."
My response: While "outbreeding depression" as you refer to it may not have occurred, the possibilty that it did certainly does exist. Even if outbreeding depression doesn't exist, the yearly propagation of fish stocked into the Bone Lake brood stock and the re-stocking of fish from the eggs taken there and stocked back into Bone certainly extends the possibility of the perputation of those known small growth fish.
Combine that with recent new information that this stocking of small growth fish from BOTH Spider Lake AND we sadly now learn, two additional hatchery uses of Spider Lake fish AND even sadder yet, two hatchery uses of eggs from Callahan Lake and this issue becomes far more important, and certainly cannot be considered "minor." In two of those five occurances, a large percentage of the eggs used for hatchery propagation for those years were from these stocks. To quote a former WDNR propagation manager, "We should have never used eggs from Callahan Lake."! Former WDNR Researcher Leon Johnson, also indicated in Technical Bulletin #49, that "most of the fingerlings stocked" in LCO in 1956, "were derived from a slow-growing population of muskellunge from Big Spider Lake."!
You further stated: "We would like to characterize our genetic stocks as outlined in Dr. Sloss' study proposal in order to minimize uncertainty about any ill effects of past mixing. But until that work is done, there is no reason to risk creating a REAL problem by introducing an admittedly fine strain but a DIFFERENT strain from Leech Lake, which COULD cause problems if stocked repeatedly into systems where locally adapted fish reproduce naturally.
My reply: Again, the WMRP has NEVER advocated stocking Mississippi River strain/Leech Lake muskies into lakes with naturally self-sustaining populations. NEVER! And we still don't, and agree fully with preserving ALL "naturally self-sustaining" populations of muskellunge. It is the non-native lakes and the native lakes that MUST be stocked to maintain a viable fishery that we have addressed.
You stated: "I have heard folks criticize WDNR for poor broodstock management, and also for being overly defensive about public criticism of those management techniques. The critics need to know that I had nothing to do with Wisconsin fishery management until 3 years ago when I moved here from Missouri."
My reply: Respectfully, we have made it clear from the very start, that we have NEVER pointed the finger at anyone within the DNR past or present for intentional "poor broodstock management." This applies especially to you in your short tenure here.
You continue: "My new Wisconsin colleagues know (probably to their chagrin!) that I am not afraid to raise questions and concerns about past management practices. But our muskellunge propagation system is not high on my list of concerns.
My reply: Actual muskellunge propagation should not be your concern. However, as Upper Chippewa Basin Supervisor, I would hope that it would be your concern that current stocking practices involve yearly stocking of lakes in your drainage responsibilty with fish from the Wisconsin River drainage and the Woodruff hatchery. We have learned that this is done purely on an administrative "district/lake" responsibility basis of an imaginary line, without regard to lake drainage. Your area lakes biologist is on record, again this week in the Sawyer County Record, as stating "...if you take a strain from one watershed to another in trying to improve that stock, you won't do it. That will lead to a decline in that stock's ability to sustain itself. That is biologically and ecologically unsound." THAT is exactly one of the many points that we have tried to make. We sincerely hope that you will look into this further and see that it is corrected.
You end by saying: "Of course, it would be nice to have the moral and financial support of people who care about the fish we are entrusted to conserve on their behalf."
My reply: Dave, that is the cruix of this whole matter. We DO CARE, and are fully prepared to support both "morally and financially," as well as with manpower where necessary/needed, furthering sound management goals. We have had several misunderstandings in the recent past, and it is our sincere hope that we can communicate more in the immediate future to clear things up and get back on the track of working together to improve our Wisconsin muskellunge fishery. This willingness to work together in the future has been made clear by the State's Musky Committee co-chair and DNR point man, Tim Simonson this past week, and I hope the same is in the immediate future for you, I and the WMRP.
Respectfully submitted,
Larry Ramsell
Wisconsin Muskellunge Restoration Team
www.WisconsinMuskyRestoration.org |
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Posts: 714
Location: Rhinelander, WI | Steve, I don’t see where Mr. Ide’s thoughts conflict with Michael’s thoughts. Could you please expand on what you are referring to. I thought the two posts complemented each other pretty well.
Regarding his comments on study, in my opinion I don’t think he was talking about Dr, Sloss’s genetic study, he specifically mentioned growth studies, which typically take many years of watching and sampling fish to perform. In fact Mr. Ide points out the importance of using genetics as evidenced by the following quote:
“Using genetics, we can make a tree that shows, by number of genetic changes, how far a particular individual is from the trunk of the tree, or if an individual is in another branch of the tree. (This is done by sequencing part of the DNA in the genome, the DNA in your mitochondria is identical to that of your mother, the DNA in the X chromosome identical to your father. Thus both Maternal and Paternal lineages can be followed.)”
I think Dr. Sloss’s research could be the most important stuff going on for the future of Wisconsin Musky fishing. We as musky fanatics need to insure this work keeps going. It could possible answer all the question regarding which fish to stock. I think both Michael and Mr. Ides’ posts point this out.
Nail A Pig!
Mike
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Posts: 32886
Location: Rhinelander, Wisconsin | Mike, Sure, here's what he said re: the proposed study. This is, in context, referring directly to Dr. Sloss's proposed work and in fact mirrors what the WMRT originally said regarding that proposed project:
'15. Should there be another study on muskie growth? On one of the posts it is indicated that Wisconsin is going to ask for federal money to study muskie growth. This sounds like a tactic to create or pay for jobs that already exist. If you suspect that the funds are being misused, you can use the Freedom of Information Act to see how the money is being used. I have spent thousands of my own money in the past gathering such documents, so it can be done.'
It's not even questionable to my mind what that statement inferred.
The overall premise of his post on MH was that it's the fish, and that it's as easy as whether one should use sunscreen, just stock Leech Lake muskies and our problems are solved. He does qualify those comments somewhat, but the average reader would take home only the Sunscreen/stocking comparison.
This comment from Michael:
'Which of these scenarios describes the situation for muskellunge in the midwest, we won't know until the appropriate, high-resolution markers are developed and applied.'
directly conflicts with number 15 above, wouldn't you say?
Another:
'Stocked fish may still impact the native fish. They can compete for forage with the indigenous (reproducing fish) and hence affect growth rates and result in a lower "effective population size"of breeding fish - perhaps a concern for native pop'n's facing multiple stressors.
Here's an account of some WI lake trout stocks:
http://www.dnr.state.wi.us/org/caer/ce/news/on/2003/on2003610.htm
The take-home message here is that despite many decades of stocking from the Great Lakes sources, the indigenous, inland stocks were better suited to local conditions. The stocked fish made virtually no contribution to the fishery! '
I read this as a caution against the principle promoted here:
'3. Is the growth rate and the penultimate size the most important thing in selection of muskies for stocking? These are related, as slow growing adaptees do not reach the ultimate size of rapid growing fish. Thus, selection for rapid growth rate will probably lead to the largest ultimate size. In theory, selection at the hatchery level should be searching for surviability, growth, resistance to disease, ability to reproduce etc. In the case of muskies that are destined to be sportfish, where size matters, selection by size trumps these other charachteristics.'
Didn't Dr. Casselmans work indicate that the largest specimens tend to exhibit moderate growth and great longevity?
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| Dave,
Outbreeding depression keeps popping up here. In an AFS publicationdated Feb 2005 (vol 30 no.2) I find the statement:
"Scientific evidence exists for inbreeding, but not for outbreeding in aquaculture fishes."
Can you point to documented cases of outbreeding depression in Muskellunge that we can reference.
Thanks,
Bob |
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| Steve,
I've been trying to get some details on Casselman's cleithrium data, but have not found it to be very useful mainly because what I have is all averages. I'm sure the data is good, but I find the raw data more useful than averages.
I can tell you that the MN DNR has been quoted that the MS strain is reaching 50 lb is 12 years.
(reference MH May 199 issue). A recent 62 lb muskie in canada was 55.5 inches long at age 17. Compare that to 12.9 years for female muskies in LCO to reach 40 inches. (WDNR data - margenau/Avelallement Effects of a 40 inch Minimum length limit). The most frightening aspect is that this study indicates the Muskies in LCO take 5.7 years to grow from 34 to 40 inches in this low density population. Many Wisconsin Biologists have documented that long life spans do not necessarily correlate to large muskies. (Margenau/Johnson studies).
Dave,
were you able to net any large females from LCO this year that can provide us with age information on those large fish? Is the DNR working with the Native Americans to obtain genetic/Cleithrium data on any large specimens that are harvested? It seems this would be a great source of data that is typically unavailable to researchers/interested anglers.
thanks,
Bob
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| Dave,
You stated the following:
"The second method is much simpler. We simply analyze netting and creel survey data from lakes that are entirely dependent upon stocking, and if we see fish over 50" long, we know that potential exists. Lakes all over Wisconsin reflect this potential. These combined phenomena help to explain why Wisconsin biologists do not suspect broodstock genetics to be an important factor limiting the relative abundance of trophy-size muskellunge in this state today."
I've analyzed the netting data from lakes in the lower Chippewa River basin and based on that data, I repectfully disagree that you are finding 50" fish in your nets - at least in the area in which I live. I received the Information from the fisheries people down here a while back, and have the data from 11 samples. Of the 741 adult fish (age 4 or older) sampled, there was only one musky sampled equal to or over 50 inches. (51 inches from Dells Pond) It's interesting to note that this 14 year old 51 inch fish was born in 1982 - According to WDNR stocking database there was no Musky stocking by the WDNR in that time period in Dells pond. So, apparently it's not a stocked fish. If this simple method is valid it should prove the stocked fish do not reach 50 inches in the Lower Chippewa Basin.
As for needing long life spans to get large - the information shows that fish in NW Wisconsin average 39.6 inches at age 15.
If any of you have specific questions on the data, let me know. The lakes sampled range from small to large and include Wissota, Holcombe, sand, Long, Old Abe, Cippewa Falls Flowage and Dells Pond. For those of you in NE Wisconsin - can you find similar netting data? I'd love to do a comparison between hatchery districts.
Thanks,
Bob |
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Posts: 32886
Location: Rhinelander, Wisconsin | 'Many Wisconsin Biologists have documented that long life spans do not necessarily correlate to large muskies. (Margenau/Johnson studies).'
'Didn't Dr. Casselmans work indicate that the largest specimens tend to exhibit moderate growth and great longevity?'
Just to make a point, these two statements are not contradictary. Moderate growth and great longevity would be what was mentioned for the Canadian fish at 17 years, I think. If that fish survived to 24 or 26 years, I wonder what it would measure then. I'll wait for Mr. Nueswanger's resoponse on the rest.
As far as growth rates here in my home area, I believe that the fish from Pelican, for example, are about 13 to 15 years old at 50". I am also pretty certain there has never been a legitimate 50# fish from Pelican. I think an Oneida Co. fish I caught a season ago at about 40# was about 15 years old, and went from 42" to over 50" in about 4 years.
Of course, that doesn't mean all 15 year old muskies here are guaranteed to reach 50", I'm pretty sure that doesn't happen anywhere.
Here's some references to look to about outbreeding depression, all from the source Bob mentioned:
http://www.fisheries.org/html/fisheries/F2808/F2808p10-24.pdf
http://www.fisheries.org/html/fisheries/F2808/F2808p10-24.pdf ( this is a good read, interesting stuff)
http://www.fisheries.org/html/fisheries/F3002/F3002p30-34.pdf Here's the one Bob is referring to. Read the entire document ( it's interesting. Unless you are here because you like to see a 'train wreck', you'll find this a worthwhile read) read about propagated fish and wild fish, understand the context, and the reference is better understood. It basically was a query, as I understand it.
Here's a book I have to get, being a Black Bass freak:
http://www.fisheries.org/html/publications/catbooks/x54031.shtml
Do a search by hitting control and the F key, type in 'outbreeding depression' and hit enter
http://www.fisheries.org/html/publications/catbooks/bb.shtml More Bass conversation, do the search to cut to the chase if you're not distracted by the content, which I was...
And so on.
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Posts: 7
| Bob,
Because so few people have studied muskellunge, there have been no studies done of inbreeding depression and outbreeding depression in this species. The long generation time of muskellunge is another problem that puts the question beyond the time-frame of an M.Sc. or Ph.D. project utilizing controlled crosses. Outbreeding depression remains one of the hypothesized causes (along with habitat degradation) of failed reproduction in once self-sustaining muskie populations in the midwest (Margenau 1999).
Management agencies throughout North America are re-evaluating their fish propagation programs as this and other genetic risks are identified.
Here are summaries of some recent studies of outbreeding depression. I apologize for the technical content. Skip to the end of each abstract if you'd just like the take-home message. Send me an email if you'd like the full papers.
Mixing Stocks of Largemouth Bass Reduces Fitness through Outbreeding Depression
Author Philipp, DP; Claussen, JE; Kassler, TW; Epifanio, JM
Affiliation Center for Aquatic Ecology, Illinois Natural History Survey, 607 E. Peabody Drive, Champaign, Illinois 61820,
Source Black Bass: Ecology, Conservation, and Management. pp. 349-363. American Fisheries Society Symposium [Am. Fish. Soc. Symp.]. Vol. 31.
Evolutionary theory predicts that differential selection pressures coupled with a restriction in gene flow among populations occupying distant habitats or isolated areas will result in the divergence of those populations and ultimately in the generation of discreet gene pools (or stocks) that are adapted to their local environments. Based on this theory, we can make two fundamental predictions concerning the outcome of a stock transfer (i.e., the introduction of fish from one or more non-native stocks into the habitat of a divergent, but native, stock). First, because of local adaptation, we predict that the introduced, non-native stock will be less reproductively fit than the native stock in that environment (Stock Transfer Prediction 1). Second, in cases where some portion of the transferred stock survives to maturity and hybridizes with the native stock, we further predict that this new hybrid population will have reduced fitness compared to the original, native stock (Stock Transfer Prediction 2). Such a loss in fitness is termed Outbreeding Depression. To test these two basic predictions empirically, we used genetically-tagged stocks of largemouth bass Micropterus salmoides from Wisconsin, Illinois, and Texas, as well as a stock of Florida bass Micropterus floridanus from Florida in a series of "common garden" experiments in different geographic regions within the United States (Minnesota, Illinois, Texas, and Florida). In each of the four geographic regions, the native stock had not only superior rates of survival and growth, but also, and more importantly, superior rates of reproductive success. These results are highly consistent with our first prediction. Moreover, the absence of fully assortative mating resulted in extensive interbreeding among stocks in the experimental ponds. We tested the effect of this interbreeding on the fitness of the recipient, local Illinois stock. Here, interbreeding of the native Illinois stock with the transferred stocks led to a hybrid population with more than a 50 percent reduction in reproductive fitness relative to the original, local Illinois stock, an outcome consistent with the second prediction. Our results clearly indicate the long-term negative consequences that accrue from transferring largemouth bass stocks. We recommend suspending stock transfer activities and replacing bass management programs that continue to erode the genetic resources of this valuable group of fish with programs that conserve and protect their genetic diversity.
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Outbreeding depression in hybrids between spatially separated pink salmon, Oncorhynchus gorbuscha, populations: marine survival, homing ability, and variability in family size
Gilk, SE; Wang, IA; Hoover, CL; Smoker, WW; Taylor, SG; Gray, AK; Gharrett, AJ*, Environmental biology of fishes [Environ. Biol. Fish.]. Vol. 69, no. 1-4, pp. 287-297. 2004.
Abstract Hybridization between distinct populations and introgression of nonnative genes can erode fitness of native populations through outbreeding depression, either by producing a phenotype intermediate to that of both contributing genomes (and maladapted in either population's environment) or by disrupting distinct coadapted complexes of epistatic genes. In salmon, fitness-related traits such as homing ability or family-size distribution may be eroded. Geographically separated pink salmon populations were investigated in repeated trials in independent broodyears (odd and even). Hybrids were made between female Auke Creek (Southeast Alaska) pink salmon and Pillar Creek (Kodiak Island, approximately 1 000 km away) males; hybrids and their offspring were compared to offspring of control crosses of the same females with Auke Creek males. Parentage assignment from microsatellite analysis was used to improve estimates of survival and straying and to examine variation of family size. Hybridization reduced return rates of adults (a proxy for survival at sea) in the F sub(1) generation in the odd-year broodline (p < 0.0001) but not in the even-year broodline (p = 0.678). Hybridization reduced survival in both the odd- and even-broodyear F sub(2) (p < 0.005 and p < 0.0001). Hybridization did not appear to impair homing ability; weekly surveys revealed similar straying rates (approximately 2%) by both hybrid and control fish into nearby (approximately 1 km) Waydelich Creek in both generations in both trials. Hybridization did not increase the index of variability (sigma super(2)/mu) in family size. Decreased survival in the hybrid F2 generation supports an epistatic model of outbreeding depression; nonepistatic effects may have contributed to reduced survival in the odd-broodyear F1 hybrid fish. Outbreeding depression in hybrids of geographically separated populations demonstrates that introgression of nonnative fish can erode fitness, and should be recognized as a potential detriment of both aquaculture and management practices. |
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| Michael and Steve,
Thanks for the information - fascinating stuff. Sounds like what happened on LCO.
I notice in the book "Managing Muskies" that Casselman and Crossman show that the Muskies in Bone, LCO and Big Spider Lake are among the slowest growing Muskies he found - anywhere. (Table 2 page 100)
On a side note - I see that Casselman and Crossman thanked Larry Ramsell for all of his help with the Cleithrium project at the end of that chapter.
Bob |
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Posts: 32886
Location: Rhinelander, Wisconsin | Bob,
Defining 'anywhere' as 18 studies done in 1936 to 1982 on limited number of waters is a bit misleading. Note the 101 rating in that chart listed as 'lakes and drainage areas in Northern Wisconsin', and the fact the Chautauqua fish were 'listed' at a value of .03 less than the .84 Bone, LCO, and Big Spider. MuskieFIRST held an outing with a very active MI group out there on Chautauqua a couple years back that produced 74 muskies in 3 days from about 50 anglers, and two were over 50". Note also, that the data from the .84 stat from Bone, LCO, and Big Spider was apparently combined, as was the stat from Pennsylvania at 105, streams of Kentucky at .94, and waters in Michigan at .97.
The conclusion apparently drawn from this, quoted from page 100, states,"It is apparent from these indices that populations of Muskellunge in streams and relatively unexploited small lakes are significantly slower growing than the standard. Populations in lakes at the southern part of the range are faster growing. Growth of Muskellunge in large rivers is very similar ( ST. Lawrence River-95%98% and 99%, Niagra-97%)"
As far as sounding like what happened on LCO, from what I understand the chances are VERY slim that's occured there. Not impossible, just very slim. I will do everything I can to support Dr. Sloss's work to completion so we can find out for certain.
Regarding the 1984 Muskie Symposium that was responsible for creating the AFS Special Publication 15, I assisted in promoting and setting the event up, and attended the LaCrosse symposium. I had a blast, too! The company I worked for in 1984 was a major financial sponsor, as was another I was working for at the time, Lowrance Electronics. We worked very hard to raise the sponsorship funding with the help of Steve Quandt, Dick Rose, Darrel Weihert, and many others. Larry was very actively involved there, too, as he has been in many more events since that time.
Here's a close up of that page...
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 IMAG0001.JPG (95KB - 283 downloads)
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