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Bill Babler

Lake Biologist is Aware of the Dead Gizzard Shad

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Got a Text from Shane Bush, our Biologist and he is aware of the dead shad. He also stated he is not aware of the crappie or bass, but will do more research. If you have any pictures of dead game or pan fish, please post them.

He attributes the death at this point to Extremely Hot Lake water, up to 93 degree in some lake areas, and he also states the thermocline is very broken due to the influx and movement of the lake.

I'm also thinking there may be an oxygen problem with the broken thermocline. "I'm, being the key word here." The fish I am seeing, and I will preface this with I have not been on the Rock for the past few days, were adult Gizzard shad, some of the biggest I have ever seen in Table Rock.

From our family resort up on Lake of the Ozarks, we used to see Shad of this size and age and we always called them Hickory Shad as I'm sure some of the mature fisherman on that lake still do.

Lets not get our panties in a bunch quite yet, Shane and his crew are aware of it and I will try my best to keep you updated with correct and current information as it becomes available.

Good Luck

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That's very interesting stuff Bill. Thanks for posting that.:-)

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It's always interesting to hear you relay information from Shane. Nice to get some scientific insight from him on what's taking place over the years on the lake.

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Myself and another forum member fished Long Creek area 8days ago. We seen several shad floaters, along with catfish, several fry, and a bass. Hope this is a temp thing due to water temps.

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Keeping my fingers and toes crossed it's not the LMBV again !

Maybe someone with better understanding of water conditions than me can explain why the water isn't clearing up ? Only thing I can think of is a continued algae bloom from all the nutrients that got washed in ?

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From Shane Bush, MDC fisheries biologist:

I went out to Big M last week after getting a bunch of calls about dead fish and I observed dead gizzard shad from the Shell Knob bridge all the way west to the MO/ARK line. I counted about 200 dead gizzard shad from 12-14” as well as a few scattered bass, bluegill, crappie, suckers, and white bass. I suspect that the gizzard shad are dying as a result of extremely warm water temperatures. The surface temperature was 90 degrees and when I did a DO profile, it was 84 degrees at 15-20 feet deep where the thermocline started. There is some literature that suggests gizzard shad have an upper temperature tolerance of around 83 degrees, which could explain why they are the main fish being affected. The thermocline is setting up rather shallow this year in the upper end of the lake, perhaps more than usual which could explain why this is happening this year and not others. The thermocline set up shallow during the last high water events we had in 2008 and 2011 as well. The DO profile by the dam shows cooler water at the thermocline (around 75 degrees), which would be cool enough for the shad on this end of the lake. This is probably why this event is isolated to the upper end.

http://www.swl-wc.usace.army.mil/pages/reports/remote/profiles/tabpro.htm

Fish start getting stressed and dying at DO levels below 4 ppm. I suspect that there may be pockets of anoxic water in the areas where the bass and crappie are being affected. As you know, the thermocline didn’t set up until just last month, so those sport fish could have been anywhere in the water column. Have you been catching bass deep? Have you caught them deep since the thermocline set up? I suspect that some of the bass, bluegill, crappie, and white bass observed dead could have been attributed to angling mortality, having been caught from very deep water. Their eyes were bulging out of their heads, which usually indicates barotrauma from no oxygen or being brought to the surface from very deep (see attached picture of a bass by Big M). There is a secondary thermocline set up in the upper end of the lake that starts around 45 feet and extends to the bottom. Dissolved oxygen levels were 5-6 ppm in this deep layer. I think the bass and crappie are being caught deep and when they're released into the warmer water it's tough on them. The fact that this is happening lakewide really suggests an oxygen problem, not pollution or other factors that might be killing them. Of course, these are just my thoughts based on what we know about how the dissolved oxygen sets up in these large hydropower reservoirs. This year has been very strange with water inflow and I really think the thermocline and oxygen concentrations could be doing funny things, especially trapping fish in pockets of anoxic water. This happened in 2011 in Bull Shoals Lake when all of the big striped bass and walleye were killed. It’s quite an interesting phenomenon to see how the secondary thermocline dissipates in the fall, trapping the fish that are down there. It could also vary from lake arm to lake arm as well.

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Am I understanding this correct that this fall when the deep secondary thermocline dissipates those fish will basically be left without oxygen and will more or less suffocate and we will have another fish kill them?

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