Pond Boss
Posted By: DrLuke Shock survey results - 05/11/22 09:33 PM
I the spirit of sharing and learning, which is the core of the Pond Boss forum family, I thought I'd share the results of the shock survey we had done on April 29, 2022. I used Bjornson Pond Management again, which is one of the Pond Boss advertisers. Kevin Bjornson (the owner) works frequently with Nate Herman who is also a PB forum member and contributor. They also did a shock survey for us in Sept 2017, after which we did some corrective stocking and pond tweaks. They did a great job and are really fun to work with! For any members in Iowa, they come highly recommended.
I had the repeat survey done for two reasons. One, because I wanted to see 'what's going on down there' and get a feel for who's growing and how well, and if any of the things we've been 'doing' to our pond are having the hoped impact. Second, because we had that winter kill last spring (of 2021, which I posted about). I wondered about the impact on fish numbers and classes of the various species we have. So that sets the table.
First, a few pictures will tell most of the tale:

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Posted By: DrLuke Re: Shock survey results - 05/11/22 09:34 PM
Data from all the LMB they gathered data on and tagged:
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Posted By: DrLuke Re: Shock survey results - 05/11/22 09:43 PM
and here are the relative weights:
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Posted By: anthropic Re: Shock survey results - 05/11/22 09:51 PM
Good relative weights on those bass! From what I could see, nice bluegills, too.

Do you cull fish, particularly LMB? How about feeding?
Posted By: DrLuke Re: Shock survey results - 05/11/22 10:07 PM
We had low LMB numbers, but saw all class sizes. We had strong BG numbers, and had heavy numbers in the 5-7" range. We had few BCP, and the ones we did see seemed stunted (big eyes). We got a couple of large GSH (golden shiners). No perch. No RES. No HSB.
Posted By: ewest Re: Shock survey results - 05/11/22 10:58 PM
Nice results and pics ! Time to think about harvest of small or skinny LMB. Note the high RW of longer LMB. Harvest some in the length where RW are low or falling as there is to much competition for food in that size.
Posted By: DrLuke Re: Shock survey results - 05/12/22 12:33 AM
Originally Posted by anthropic
Good relative weights on those bass! From what I could see, nice bluegills, too.

Do you cull fish, particularly LMB? How about feeding?

We had been planning to start culling under performing LMB in the 10-12" range last summer, but then the winter kill happened. Our numbers are low enough we maybe stock a few more, to boost genetics.
We do feed, TH hanging feeder. I feed from about May thru Oct, once the water temp is over 50°. I feed a mix of Optimal BG and bass pellets (buy bag of each, hand mix), twice a day 1-2 second throws (1 to start then more once they are feeding well).

I had always hoped to catch a LMB of 5 lbs, so we're pretty excited to have shocked up that 4.88 lb bass. The boss caught a 10+" BG recently that was 1 lb even. We both loved that. She holds most of our pond records on fish size.
Posted By: jpsdad Re: Shock survey results - 05/12/22 12:38 AM
Those are some fat fish Dr. Luke. So the fish kill just took the right amount of fish spurring the growth of all remaining? Very impressive survey.
Posted By: canyoncreek Re: Shock survey results - 05/12/22 12:44 AM
wow, thanks for the great pictures! What is the plan to get more YP or HSB in the pond? Or is it too late with those mega-mouthed LMB in there?
Posted By: DrLuke Re: Shock survey results - 05/12/22 01:56 AM
Originally Posted by canyoncreek
wow, thanks for the great pictures! What is the plan to get more YP or HSB in the pond? Or is it too late with those mega-mouthed LMB in there?

Interestingly, we are catching perch while fishing. And the boss even caught a 10.25" YP that was 1/2 lb in the past week. So we still have them. However, we are planning to over stock more YP this spring while our LMB numbers are low. That was actually part of the recommendations given with the formal report, based on the discussion Kevin, Nate and Wes and I had.
I'm changing gears on my bonus fish. Never did hook a HSB in the 4 years they were in there. No slight on HSB, we only stocked 25. But I am going to try SMB this time and see how they do.
We also plan to add some RES. We catch one occasionally, and our black spot is very nearly gone, but I don't mind pumping up the numbers a little. Plus RES can be a nifty bonus catch too.
Posted By: DrLuke Re: Shock survey results - 05/12/22 02:00 AM
Originally Posted by jpsdad
Those are some fat fish Dr. Luke. So the fish kill just took the right amount of fish spurring the growth of all remaining? Very impressive survey.

Yeah, I got a lesson in max biomass for my pond. Mother nature "helped me" cull...everything. But for the survivors, the extra groceries have been helpful.

'Experience is what you get when you don't get what you want'. *sad face*
Posted By: jpsdad Re: Shock survey results - 05/12/22 11:58 AM
No need for a sad face. All that was lost was the opportunity to harvest those that succumbed. The track looks good now. When you last surveyed, were a similar number of fish brought up? That looked like a pretty good sampling.

I loved that you tagged some fish. You will be able to track progress on them.
Posted By: canyoncreek Re: Shock survey results - 05/12/22 05:12 PM
so the shock boat could not shock up perch because they stay deep?

And do you suspect HSB are still in your pond or you think somehow they died in the 'kill' event? I would think if they move around in open water in schools that they also could escape the shock boat too.
Posted By: DrLuke Re: Shock survey results - 05/12/22 05:18 PM
Originally Posted by jpsdad
No need for a sad face. All that was lost was the opportunity to harvest those that succumbed. The track looks good now. When you last surveyed, were a similar number of fish brought up? That looked like a pretty good sampling.

I loved that you tagged some fish. You will be able to track progress on them.

We had zero LMB shocked at the 2017 survey, and weren't catching any either. BG were skewed to the 4-6" range. BCP were bigger (length) but very thin. No other species found, and lower numbers overall.

I have wanted to start tagging for a while now, for data tracking on growth rates and catchability.
Posted By: DrLuke Re: Shock survey results - 05/12/22 05:24 PM
Originally Posted by canyoncreek
so the shock boat could not shock up perch because they stay deep?

And do you suspect HSB are still in your pond or you think somehow they died in the 'kill' event? I would think if they move around in open water in schools that they also could escape the shock boat too.

Nate and I discussed that. His experience is HSB are not very tolerant of low oxygen sats, so were likely the first casualties of the winter kill. There could be a monster HSB lurking but seems unlikely.

And yes, I guess YP can be a challenge to collect unless present in dense numbers. This also influenced our decision to overstock more now, while LMB numbers are low. I really like YP and would love to see them build their numbers up.
Posted By: Sunil Re: Shock survey results - 05/12/22 05:34 PM
When I had my main pond shocked several years ago, we brought up a ton of Yellow Perch; this would have been in 5-8' of water, so maybe Doc's pond is deeper.
Posted By: ewest Re: Shock survey results - 05/12/22 05:45 PM
Water conductivity, temp and depth all effect/limit shock surveys. That is part of the art of shock survey analysis.
Posted By: ewest Re: Shock survey results - 05/12/22 05:52 PM
Originally Posted by DrLuke
Originally Posted by canyoncreek
And do you suspect HSB are still in your pond or you think somehow they died in the 'kill' event? .

Nate and I discussed that. His experience is HSB are not very tolerant of low oxygen sats, so were likely the first casualties of the winter kill. There could be a monster HSB lurking but seems unlikely. .

In addition HSB are more active (higher metabolism) at cooler temps so they also use up more O2 being active in winter. That plus low O2 during possible winter kill will often get the more active fish first. Also (likely not an issue here) HSB can metabolize carbohydrates from fish food that BG and LMB can't so they can become morbidly obese on fish food carbs. This makes them more apt to have O2 problems.
Posted By: DrLuke Re: Shock survey results - 05/13/22 03:18 AM
Originally Posted by Sunil
When I had my main pond shocked several years ago, we brought up a ton of Yellow Perch; this would have been in 5-8' of water, so maybe Doc's pond is deeper.

My pond averages around 8', but has lots of variation, including a 14' valley. But my suspicion is my YP numbers are very low, so the chances of shocking one up is also very low.
We hope the supplemental stocking will help get them established and reproducing.
Posted By: Snipe Re: Shock survey results - 05/13/22 06:00 AM
I have to enter my thoughts here..
We spend thousands upon thousands on electrofishing equipment and then measure and weigh in inches and pounds/ounces.
mm and grams are in order. It's been proven to me time after time that pounds/ounces/inches can create up to a 15% error in WR and bad assumptions are made because corners were cut on accuracy.
This is something I don't think is "good" in fisheries management, if it isn't as accurate as possible, how can you adjust or manage with faulty data????
Sorry guys, I'm OCD with this particular step.
Posted By: DrLuke Re: Shock survey results - 05/14/22 04:29 AM
Originally Posted by Snipe
I have to enter my thoughts here..
We spend thousands upon thousands on electrofishing equipment and then measure and weigh in inches and pounds/ounces.
mm and grams are in order. It's been proven to me time after time that pounds/ounces/inches can create up to a 15% error in WR and bad assumptions are made because corners were cut on accuracy.
This is something I don't think is "good" in fisheries management, if it isn't as accurate as possible, how can you adjust or manage with faulty data????
Sorry guys, I'm OCD with this particular step.

I did watch Nate tare his scale. I also try to examine each fish's body condition as they are measured and weighed, mainly to improve my ability to judge healthy relative weight fish.
I guess I could use a standard weight to confirm calibration. I do have some standard weights I use on my arrow scale when setting up my hunting arrows. Would that be sufficient to verify accuracy?
Posted By: esshup Re: Shock survey results - 05/14/22 04:45 AM
Water clarity will also affect the results. The fish that may be shocked and are deeper that can't be seen will be passed by. I've spend a number of hours on that boat!! LOL Great people.
Posted By: jpsdad Re: Shock survey results - 05/14/22 01:11 PM
Originally Posted by Snipe
I have to enter my thoughts here..
We spend thousands upon thousands on electrofishing equipment and then measure and weigh in inches and pounds/ounces.
mm and grams are in order. It's been proven to me time after time that pounds/ounces/inches can create up to a 15% error in WR and bad assumptions are made because corners were cut on accuracy.
This is something I don't think is "good" in fisheries management, if it isn't as accurate as possible, how can you adjust or manage with faulty data????
Sorry guys, I'm OCD with this particular step.

Kenny, I agree that the degree of precision is very important. Like you I would prefer mm and grams because these units lend to very good degree of precision for fish that are > 5" in length. mm and grams are easy to read from scales and tapes.

That said. A similar degree of precision can be obtained if one has sufficiently sensitive measuring tools. For example, if a English unit tape is divided into 1/32 of an inch AND if the one taking the measurement doesn't take shortcuts of rounding then the degree of precision is actually just a tiny bit better than mm. Even so, a tape with mm is the hammer and the 1/32" scale is a rock. I would much rather drive a nail with hammer and than a rock because it is the most appropriate tool. So same goes for the tape. Your measurement will not need conversion into decimal notation and it is far easier and faster to take the measurement very accurately with a tape graded in mm.

A weight scale needs to have sufficient sensitivity to measure small increments of change. Some scales display a greater degree of precision than they are actually sensitive to. But if grams are the degree of precision sought, the scale must be sensitive to 1 gram increments. So this is easily checked (though most instruments declare sensitivity) by adding the increment to an existing weighed item and checking to see if the increment registers. If measuring in pounds on a decimal scale the scale must provide measurement in 1 thousandths of lbs and be sensitive to register .001 lb increments.

The problem with rounding and degree of precision is very much exacerbated with fish at the smaller end of the spectrum becoming more muted with large fish.

In looking over the LMB in the table, I think the surveyors may have attained a very acceptable degree of precision. The length measurements seem to be incremented to the nearest .05". So the tape was probably 1/10 graded with possible 1/2 ticks. Whether the tenths were half ticked or not, the data collected suggests that the measurements take were taken with care either to the finest degree of precision graded on the tape or possibly making additional effort to record precision finer than the tape graduation. The nearest .05 (1/20th) inch is a little larger than a millimeter by ~ 0.27 mm. So on the first fish, assuming a very accurate measurement to the nearest .05 inch the variation or uncertainty in relative terms is less than 9 parts in 10,000. Don't know if this alarmed you but the number of exactly 13" did catch my attention. With degree of precision at 0.05 this did seem a little odd but that doesn't of course mean that they were not 13" to the nearest 0.05"

On the weight end, increments of 0.01 lbs is about 4.5 times greater than grams. Assuming the sensitivity to 0.01 lbs the uncertainty of measurement relative to a gram sensitive instrument is about 4.5 parts in 1000 for first and lightest fish. The parts uncertainty for larger fish is less than that. All in all, there was sufficient precision here I think but one surely does not want to pull out a fish de-liar and round to the nearest quarter or half inch. This would yield results that are not very accurate.
Posted By: JiminKY Re: Shock survey results - 05/27/22 05:19 PM
Nice photos! I'm new this lake management and wondered if you had any opinions about our specific lake fish survey.

Our lake is about 80 acres. Its deepest point is 23 feet. It's spring and watershed fed. The watershed is 1.2 sq miles of mixed residential and farm areas. It's about 58 years old and is part of a 300-home social club (a.k,a. an incorporated HOA) about 20 miles from Louisville, KY. Most of the catches are released, and we have a rule that "bass between 12 and 16 inches shall be released. Nor more than two bass larger than 16 inches may be taken per day. No more than 6 crappie larger than 9 inches may be taken per day, crappie between 12 and 15 inches are limited to 2 per day, and larger crappie are limited to one per day.". That might be out of date or even backwards, but I suspect it was based on paying $12 each for 1 to 1.5 pound bass. It's cheaper to hand out grocery store fish vouchers.

The main objective is to have a productive large mouth bass fishery with plenty of crappie and sunfish and things for the kids to catch. Over the years it has been stocked with LMB, crappie, pan fish (i.e. sun fish, red ear, etc.), grass carp and channel catfish. the Channel cats are in two classes: 8 and 16 pounds. That probably corresponds to the stocking plans because there are very few spawning structures for them here. The crappie were over fished by a member who is no longer here and have started to return after 2 years of being rare catches. The main bass food is gizzard shad. The number of Shad bait balls look normal this year.. A few 35# flat head catfish have been netted but we don't stock them.

The Club has tried to manage the lake but it has been a "Let's put more fish in and see what happens" type of approach. The lake chemistry (dissolved O2, temp, alkalinity, pH, conductivity are all in the proper ranges. We're lucky to be in a limestone area. Nitrogen, and phosphate test are normally too low to measure with droplet tests. Ecoli is very low since 1974 when the septic regs went into place (e.g., 5 to 9 col/100 ml). (We test a lot because we added the lake to a KY satellite remote imaging project which is studying how to manage water quality from the overhead). Our main issues are milfoil, silt and an unreliable and insufficient annual lake budget.

Our first algae bloom this year seemed early. Normally, at this time and most of the summer, or Secchi disc would read 24 inches. This year it has been 43 inches all spring. This year we're catching more 4 to 8 pound bass than usual. It could be the same fish caught over and over. The anglers have not been providing length and weight info. as we request.

Now to the questions: Two seasons ago, (before we've found this awesome community) the State did an electro-shock survey (see photo). They recommended we stock a lot of LMB so they would reduce the gizzard shad population and then start eating the pan fish. (Something about the shad not having bones which makes it preferred over pan fish.). The strategy was to reduce the gizzard shad and pan fish which would reduce the load on the food chain and give larger but fewer pan fish, crappie and bass. We put in 130 or so 1 to 1.5 lbs. LMB that year. They look very healthy when I feed them Purina sport fish food for fun, not for sustenance (I seem to be the only angler here who can't catch them (and then weigh) them.)

We noted that the state didn't weigh any of their samples, and they have discontinued that program and we can't afford to survey again. I'm considering netting them when I try to feed them but it would be a very geographically limited sample, and probably only sample the pellet fed fish we put in last year.

We are trying to get smarter with the Pondboss and all y'all's help (I got the book but not the tee shirt ;>) ).. Any comments the survey or their conclusion, as well as any comments on what we did wrong, or suggestions to improve it would be greatly appreciated. Many thanks.

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Posted By: esshup Re: Shock survey results - 05/28/22 03:10 AM
The Gizzards are eating the base of the food pyramid for the rest of the fish in the lake. A low dose of Rotenone might be beneficial. That will kill a lot of the Gizzards but very few of the other fish.

The LMB in the survey are only able to eat the smaller Gizzard shad and not the adults. A Gizzard shad can grow from hatching to being larger than the LMB in the survey can eat in less than a year. Without something in there to help hammer the Gizzard shad, the lake will slowly decline because they are eating a lot of food that would be going to growing the small panfish.

If it was legal to stock Hybrid Striped Bass in there, that is what I'd do - on the order of 20 or so per surface acre. They will not reproduce in there, and after they are 5#-7+# then you can start allowing some to be removed. You could stock the HSB at 4"-6" fish. Bigger than a lot of the bass could eat but they'd still be able to target the small GSD in there.

There is a local lake that is 360 acres. The last net survey that the DNR did showed 60% of the fish in the lake by weight were Gizzard Shad.

If the bass are eating the fish pellets, look at buying some Stubby Steve's pellets to fish with. The bass will hit those. https://stubbysteves.mybigcommerce.com/brown-fish-food-pellet/
Posted By: ewest Re: Shock survey results - 05/31/22 05:51 PM
An adult GShad from a northern lake. If they can survive with no winter kill this is what you get.

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Reduce GShad numbers by electroshock, seine, rotenone or other methods.

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Posted By: anthropic Re: Shock survey results - 05/31/22 09:29 PM
Eric, would it be possible to keep gizzards under control by a combination of electroshock culling and light use of rotenone, even if the initial LMB population didn't contain enough bigguns to control them?
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