03-02-2014, 07:19 PM
[#0000FF]Sheer numbers planted are not the only factor in how many grow to larger sizes. The greatest majority of those numbers (planted) are "sac fry"...newly hatched with the egg sac still on them. They are less than a half inch long. At that size, even the gizzard shad feed on them...along with the young of all the other species in the lake. They might be at the top of the food chain when they get bigger but they are totally at the bottom until they get above about five or six inches. To get there they have to dodge and compete with all the other fish in the lake. Until they get big enough to feed on gizzard shad those shad are their main competitors for zooplankton and other small fry food.
Some years DWR plants a few thousand fry that are 3 to 4 inches long. Those obviously have a higher survival percentage but they are also expensive to hold and feed in rearing ponds for several months.
Also, when the sac fry are planted, there can be a higher mortality rate for them just based upon their overall strength and survivability. Proper timing of collection of eggs and milt...from the two different species (white bass and stripers) is important. And since those two species are far apart at spawning time (Utah Lake and Powell) there can be a problem in getting eggs and milt together in a timely fashion. That can affect fertility percentage as well as "toughness" of the hatchlings.
In the days before DWR instituted the Utah wiper hatching program they bought high quality sac fry from states where white bass and stripers were spawned side by side and the eggs promptly fertilized in suitable surroundings. Those were the days when megathousands of wipers were planted and we experienced wide open wiper fishing. Even used to get boils all over the lake. It has been years since those fun times.
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Some years DWR plants a few thousand fry that are 3 to 4 inches long. Those obviously have a higher survival percentage but they are also expensive to hold and feed in rearing ponds for several months.
Also, when the sac fry are planted, there can be a higher mortality rate for them just based upon their overall strength and survivability. Proper timing of collection of eggs and milt...from the two different species (white bass and stripers) is important. And since those two species are far apart at spawning time (Utah Lake and Powell) there can be a problem in getting eggs and milt together in a timely fashion. That can affect fertility percentage as well as "toughness" of the hatchlings.
In the days before DWR instituted the Utah wiper hatching program they bought high quality sac fry from states where white bass and stripers were spawned side by side and the eggs promptly fertilized in suitable surroundings. Those were the days when megathousands of wipers were planted and we experienced wide open wiper fishing. Even used to get boils all over the lake. It has been years since those fun times.
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