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WHY DO THEY NOT STOCK MORE WALLEYE ???

  • rippin-lips
    Participant
    Kearney
    Posts: 52
    #1319945

    After watching this years very impressive egg collection for one morning at Sherman it made me wonder. How many of these do they stock back in the lake. After looking at the G&P stocking reports I was shocked!!! Only 160,000 1.5″ fry were put back in 2010. How many of those are just fish food???

    While lake MCconaughy was stocked with over 2,000,000

    salmo_trutta
    Participant
    River Falls,WI
    Posts: 653
    #961830

    Im not near the lake youre talking about but the stocking numbers reflect the active reproducing popuation of the lake. If Sherman is only getting 160,000 fry compared to 2 million at other lakes, that would suggest that Sherman has a more productive class of walleyes than Mcconnaughty. On the other hand your also part correct about stocking to feed larger fish, which is a practice I just researched. Colorado stocks some of their reservoirs with salmon and trout with the intention of feeding the lake trout population within the system. Does Mcconaughty have alot of trophy class fish caught?

    mb376
    Participant
    Lincoln, Nebraska
    Posts: 120
    #961861

    Daryl will probably give you the best answer, but bigbones is probably on the right track. I understand that Sherman is one of the few reservoirs in Nebraska which has documented natural reproduction and recruitment, and I believe Mcconaughy is maintained almost solely by stocking. Mconnaughy is also about 10 times the size of Sherman.

    Brian Robinson
    Participant
    central Neb
    Posts: 3914
    #962026

    Plus, Mac has a ton of alewife in it, where Sherman is a shad based fishery. I’m sure that has something to do with it as well.

    whitetips2
    Participant
    Posts: 100
    #962629

    OK, let’s play some “number games”.

    Our spawning crews collected walleye eggs at Sherman, McConaughy and Merrit this spring. All together we collected over 500 quarts of walleye eggs, that would be somewhere in the neighborhood of 60 billion walleye eggs. We will see at least half of those eggs hatch in our hatcheries. That walleye production will be sufficient to stock all the walleyes our fisheries managers request for all Nebraska waters where we stock walleyes. We also trade some walleyes to other states in return for trout, wipers, channel catfish, etc.

    So, we “only stocked” 160,000 walleyes in Sherman last year, but we did stock walleyes there; we stock walleyes in all the waters where we collect walleye eggs. Those 160,000 1.5-inch fish that were stocked in Sherman last year were actually 40-day old fingerlings. We also stock a lot of 4-day old walleye fry, fish that are much shorter than an inch, almost too small to see with the naked eye, in some Nebraska waters. Over the years we have discovered that a variety of walleye stocking strategies work on Nebraska waters. Fry-stocking works on some waters and on other waters fingerling stocking works better. When we stock walleye fry, we typically stock them at a 1,000 fry per acre rate. When we stock walleye fingerlings, we typically stock them at a 50-100 fingerling per acre rate. So, yes, we stock A LOT more walleyes in waters where we stock walleye fry, but it is very much a numbers game and you better believe the survival rate for 4-day old fry is A LOT lower than the survival rate for 40-day old fingerlings. Notice also that our stockings are done on a “per acre” basis–we stock a lot more fingerlings in McConaughy compared to Sherman because McConaughy is a larger reservoir.

    By the way, Sherman is one Nebraska reservoir where we have very good natural reproduction of walleyes and probably do not need to stock any walleyes. But, some anglers believe that the more fish you stock the better the fishing will be, so in addition to the natural reproduction at Sherman, we also stock walleye fingerlings.

    At Sherman we stocked walleye fingerlings in alternate years, odd-numbered years 1995-2009. We also stocked walleye fingerlings in Sherman in 2010. Since 2000 we have stocked over 817,000 walleyes in Sherman. If even a small percentage of those fish survive, that would be all the walleyes that water could support and then some.

    Between natural reproduction and stocking, there are plenty of walleyes maintain the Sherman walleye population and fishery. Waters can only support so many fish and that is especially true for a top-of-the-food-chain predator like walleyes. Stocking more walleyes is not necessarily a good thing and in fact stocking more fish may not produce any more fish for anglers to catch. Walleye populations wherever walleyes are found are typically maintained by large year-classes that are produced once every 3-5 years. That is the case whether those walleye populations are stocked or maintained entirely by natural reproduction. That is the case at Sherman as well as all other walleye waters in Nebraska and no amount of stocking will change that.

    How many of those fingerling walleyes end up being nothing but fish food? Well, a lot of them; by far most of them! Small fish live in a “fish eat fish” world and the percentage of young fish that survive their first year is very low; in most cases less than 1%, almost always less than 10%. But, that is in fact the reason fish produce a tremendous number of young! By collecting walleye eggs, hatching and then re-stocking them, we can increase survival somewhat, but the fact of the matter is most of those fish are not going to survive, ever, any year, under any conditions. However, enough will survive to maintain the population and that is all we can ask for.

    Daryl Bauer
    Fisheries Outreach Program Manager
    Nebraska Game & Parks Commission
    [email protected]
    Bauer’s Barbs and Backlashes

    rippin-lips
    Participant
    Kearney
    Posts: 52
    #962876

    Quote:


    By the way, Sherman is one Nebraska reservoir where we have very good natural reproduction of walleyes and probably do not need to stock any walleyes. But, some anglers believe that the more fish you stock the better the fishing will be, so in addition to the natural reproduction at Sherman, we also stock walleye fingerlings.

    At Sherman we stocked walleye fingerlings in alternate years, odd-numbered years 1995-2009. We also stocked walleye fingerlings in Sherman in 2010. Since 2000 we have stocked over 817,000 walleyes in Sherman. If even a small percentage of those fish survive, that would be all the walleyes that water could support and then some.

    Between natural reproduction and stocking, there are plenty of walleyes maintain the Sherman walleye population and fishery. Waters can only support so many fish and that is especially true for a top-of-the-food-chain predator like walleyes. Stocking more walleyes is not necessarily a good thing and in fact stocking more fish may not produce any more fish for anglers to catch. Walleye populations wherever walleyes are found are typically maintained by large year-classes that are produced once every 3-5 years. That is the case whether those walleye populations are stocked or maintained entirely by natural reproduction. That is the case at Sherman as well as all other walleye waters in Nebraska and no amount of stocking will change that.

    How many of those fingerling walleyes end up being nothing but fish food? Well, a lot of them; by far most of them! Small fish live in a “fish eat fish” world and the percentage of young fish that survive their first year is very low; in most cases less than 1%, almost always less than 10%. But, that is in fact the reason fish produce a tremendous number of young! By collecting walleye eggs, hatching and then re-stocking them, we can increase survival somewhat, but the fact of the matter is most of those fish are not going to survive, ever, any year, under any conditions. However, enough will survive to maintain the population and that is all we can ask for.

    Daryl Bauer
    Fisheries Outreach Program Manager
    Nebraska Game & Parks Commission


    Wow thats a lot of information Thanks for the reply Daryl

    With all that being said. Since Sherman is really one lake that has great natural reproduction, If the walleye at Sherman were left un-touched to do their own thing do you think we would end up with more or less than 160,000 1.5″ fingerlings per year?

    One more question running through my mind. It seems that the biologists had great sucess in gathering up fish to collect eggs from. Do they have any idea what percentage of the spawning females in the lake are netted and milked? What percentage are still left to naturally spawn in the lake?

    whitetips2
    Participant
    Posts: 100
    #963026

    I am not sure I understand your question, if the walleye were left “un-touched” to do their own thing if you would end up with more or less than 160,000 1.5-inch walleyes? Do you mean if they were left “un-touched” would they produce more than 160,000 1.5-inch walleyes by themselves?

    The dam at Sherman is closed to fishing after dark during the walleye spawn and the walleyes in Sherman naturally-produce more than 160,000 walleyes. They would produce just as many if the dam was open to fishing after dark during the walleye spawn. Research on Sherman has found walleye egg densities of over 650 walleye eggs per square meter on the rocked face of the dam. Now, I do not know off the top of my head the total area of the spawning habitat on Sherman, but there are billions of walleye eggs produced each year and a survival rate of only a fraction of a percent would produce more than 160,000 1.5-inch walleye fingerlings.

    Without doing population estimates I cannot tell you the percentage of female walleyes from which we collect eggs. We have not done a walleye population estimate at Sherman ever that I know of. But, we have done that on other Nebraska waters. Back in the early 1990’s we tagged walleyes at Harlan and that allowed us to calculate a population estimate. Using that information along with collecting walleye eggs at Harlan and having an angler survey going at the same time, I was able to estimate that in one spring the walleye population at Harlan produced a billion eggs. If every female walleye that was caught by anglers that spring was harvested and if every female walleye caught by anglers was full of eggs, then anglers would have “removed” 2% of the total walleye egg production that year. Our crews collecting walleye eggs that spring would have removed an estimated 4% of the total walleye egg production. That means 94% of the total walleye egg production in Harlan that spring was deposited on the rocks and again if even a small percentage of those eggs hatch and survive, that is more than enough recruits to maintain that walleye population.

    We do not have any way to come up with similar estimates for Sherman Reservoir, but I am sure the numbers would be very similar. We collect walleye eggs from a small percentage of the total adult female population.

    Daryl Bauer
    Fisheries Outreach Program Manager
    Nebraska Game & Parks Commission
    [email protected]
    Bauer’s Barbs and Backlashes

    rippin-lips
    Participant
    Kearney
    Posts: 52
    #963100

    Thanks Daryl. Watching the egg collection process was very interesting. I wish I could go back 15 years and I would pick a career in fisheries!! So much more interesting… LOL…

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