Can flathead cats control crappie?

Posted by: saint_abyssal

Can flathead cats control crappie? - 08/13/19 12:31 AM

Flatheads are unpopular among pondmeisters because they're voracious superpredators. Crappies are unpopular because they're excessively prolific and prone to stunting. It looks like their flaws cancel each other out. Would it be possible to manage a single-digit acre sized fishery based around these two species?
Posted by: Freg

Re: Can flathead cats control crappie? - 08/13/19 05:24 AM

I would guess that crappie wouldn't be enough of a food source for flatheads. Maybe if you added gizzard shad into the mix?
Posted by: RAH

Re: Can flathead cats control crappie? - 08/13/19 06:13 AM

I am getting FHM and LCS going in a half acre pond with a plan to add black crappie and then blue catfish. The idea is to have a small
batch of really big cats. The plant life is coming along very slowly due to the clay soil, so it may take me a while to build the forage base. I am not feeding. Thought about pumkinseed but have not found a source.
Posted by: Dave Davidson1

Re: Can flathead cats control crappie? - 08/13/19 08:37 AM

I'm skeptical about crappie in anything less than 20 or so acres. They have early spawns and I doubt the capability of big cats to control them.
Posted by: RAH

Re: Can flathead cats control crappie? - 08/13/19 09:19 AM

I also have a retired couple that fish my ponds:)
Posted by: Pat Williamson

Re: Can flathead cats control crappie? - 08/13/19 09:44 AM

So far no overpopulation of crappie after 5 years. Don’t think they have pulled off a spawn since the first year......
Posted by: ewest

Re: Can flathead cats control crappie? - 08/13/19 10:35 AM

If the crappie have not spawned for that long it is not because of the catfish.

It could be possible to manage the FHC and crappie if the numbers are right. Keep us posted as to results.
Posted by: Pat Williamson

Re: Can flathead cats control crappie? - 08/13/19 11:26 AM


Originally Posted By: ewest
If the crappie have not spawned for that long it is not because of the catfish.

It could be possible to manage the FHC and crappie if the numbers are right. Keep us posted as to results.


Eric I think the weather has been the deciding factor warm then cold till they give up on spawning. The catfish are CC and BC that are about 5#s . LMB are up to double digit size with a huge group of 2 year olds,
Posted by: saint_abyssal

Re: Can flathead cats control crappie? - 08/13/19 12:45 PM

Originally Posted By: Freg
I would guess that crappie wouldn't be enough of a food source for flatheads. Maybe if you added gizzard shad into the mix?

Originally Posted By: Dave Davidson1
I'm skeptical about crappie in anything less than 20 or so acres. They have early spawns and I doubt the capability of big cats to control them.

Getting mixed signals here, guys. grin cry
Posted by: SWMO 2

Re: Can flathead cats control crappie? - 08/13/19 01:59 PM

I have had crappie in my pond for years and they have never had a successful spawn as far as I know. I also had a few 20# channel cats and they eat ANYTHING, flatheads would be even worse as about all they will eat is live fish. I personally would never stock any catfish besides bullhead in a pond. I do know channel cats are popular and can be managed fairly easily. So if you really want to do it, go for it but I don't think your crappies could support the cats for long without sunfish or shad in the pond as well.
Posted by: teehjaeh57

Re: Can flathead cats control crappie? - 08/13/19 02:01 PM

FHC won't bother chasing CP under 10" once they get up to 10# or so...what I envision is a pond full of small CP and underfed FHC. The key to forage for predators is to provide multiple sources each with it's own availability during the season.

If one had a fishery full of invasive species [Carp, Buffalo, Bullhead, Green Sunfish, etc.] due to periodic river flooding it's the only instance where I would recommend ultra predator species stocking like FHC. In sandpit fisheries in NE I manage we often face dense Gizzard Shad populations due to river flooding and HSB, TM, and BC perform well utilizing that forage base and providing new angling opportunities.

I understand your logic on the CP/FHC combo, but again I suspect the fishery would yield abundant small CP and underweight FHC.
Posted by: saint_abyssal

Re: Can flathead cats control crappie? - 08/13/19 03:58 PM

Originally Posted By: teehjaeh57
underweight FHC.

Believe it or not, this is kind of something I was planning the pond around. To be more specific about the intended food web, I wanted to stock a large variety of small forage fish like Gambusia, banded killifish, non-golden shiners, non-fathead minnows, pumpkinseed, alongside the BCP and FHC.

I was hoping the flatheads would kind of struggle after they outgrew those foods. Their only food source beyond this would be the crappie themselves, I was hoping this would create a bottle neck where few flatheads achieved large size, and those that did could control the smaller ones through cannibalism. Meanwhile, the heavily predated, well-fed crappies could max out their size.

I'm a complete amateur though, so that might still be a path to both species ending up stunted. Just thought I would elaborate on the specifics I was imagining. Would being underweight ruin the quality of an FHC as a food fish?







Posted by: SWMO 2

Re: Can flathead cats control crappie? - 08/13/19 04:39 PM

Catfish have issues spawning in a pond, if you put in the correct habitat thay can but if it is not preasent odds are they will not.
Posted by: RAH

Re: Can flathead cats control crappie? - 08/13/19 04:40 PM

My experience is that the knowledgeable folks recommend against large catfish (flatheads and blue) and crappie in smaller ponds. I already have two ponds with more conventional species, so I am curious about experimenting with something different in this 3rd pond. If I am unhappy in future years, I'll dump in a bunch of lime and start over.
Posted by: TGW1

Re: Can flathead cats control crappie? - 08/14/19 07:12 AM

Pat, after four yrs of reading about your pond, it seems to me you wound up with a pretty nice lmb pond with a few nice cp in it. I know from your post here your goal was for a good crappie fishing pond. Have you considered adding more cp to the pond. I was thinking one nice winter fishing trip at Rayburn you could have more than enough cp to restock the pond with some 12"+- cp. Even you and I could put that trip together. smile I have pretty much everything we would need to do that trip. Just a thought!!
Posted by: Pat Williamson

Re: Can flathead cats control crappie? - 08/14/19 01:04 PM

Originally Posted By: TGW1
Pat, after four yrs of reading about your pond, it seems to me you wound up with a pretty nice lmb pond with a few nice cp in it. I know from your post here your goal was for a good crappie fishing pond. Have you considered adding more cp to the pond. I was thinking one nice winter fishing trip at Rayburn you could have more than enough cp to restock the pond with some 12"+- cp. Even you and I could put that trip together. smile I have pretty much everything we would need to do that trip. Just a thought!!


That sounds like a plan Tracy.
Posted by: teehjaeh57

Re: Can flathead cats control crappie? - 08/14/19 01:23 PM

Originally Posted By: saint_abyssal
Originally Posted By: teehjaeh57
underweight FHC.

Believe it or not, this is kind of something I was planning the pond around. To be more specific about the intended food web, I wanted to stock a large variety of small forage fish like Gambusia, banded killifish, non-golden shiners, non-fathead minnows, pumpkinseed, alongside the BCP and FHC.

I was hoping the flatheads would kind of struggle after they outgrew those foods. Their only food source beyond this would be the crappie themselves, I was hoping this would create a bottle neck where few flatheads achieved large size, and those that did could control the smaller ones through cannibalism. Meanwhile, the heavily predated, well-fed crappies could max out their size.

I'm a complete amateur though, so that might still be a path to both species ending up stunted. Just thought I would elaborate on the specifics I was imagining. Would being underweight ruin the quality of an FHC as a food fish?









Probably best to state your ultimate goals for the fishery and work from that perspective. It's not clear to me what you're trying to achieve.
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/14/19 03:59 PM

Originally Posted By: saint_abyssal
Originally Posted By: teehjaeh57
underweight FHC.

Believe it or not, this is kind of something I was planning the pond around. To be more specific about the intended food web, I wanted to stock a large variety of small forage fish like Gambusia, banded killifish, non-golden shiners, non-fathead minnows, pumpkinseed, alongside the BCP and FHC.

I was hoping the flatheads would kind of struggle after they outgrew those foods. Their only food source beyond this would be the crappie themselves, I was hoping this would create a bottle neck where few flatheads achieved large size, and those that did could control the smaller ones through cannibalism. Meanwhile, the heavily predated, well-fed crappies could max out their size.

I'm a complete amateur though, so that might still be a path to both species ending up stunted. Just thought I would elaborate on the specifics I was imagining. Would being underweight ruin the quality of an FHC as a food fish?


Saint,

Flatheads can control crappie, however, the result probably won't be what you desire above. Flatheads are rather aggressive and sometimes kill each other. Seems to me it would be exceedingly difficult to manage the appropriate sizes and numbers to get the desired result.

Pat's having good success so look into what he is doing.
Posted by: saint_abyssal

Re: Can flathead cats control crappie? - 08/14/19 09:20 PM

Originally Posted By: teehjaeh57
Probably best to state your ultimate goals for the fishery and work from that perspective. It's not clear to me what you're trying to achieve.

Lots of crappie and flathead of good eating size.
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/15/19 09:23 PM

This link has information that may help.

Flathead catfish can reproduce at 18 in. For it to work, you should make every attempt to harvest them once they reach this size and provide only 3 to 4 spawning receptacles per acre. You want thirty 2 lb flatheads per acre not two 30 lb flathead per acre. Gizzard shad aren't really the natural prey of flat head but it might work in a shallow BOW. Tilapia would also probably be great for forage, particularly mossambica. Feeding some behind a net might introduce a lot of forage. I would complete forgo the crappie altogether. It's not clear, even without bluegill, bass, and crappie whether Flathead would recruit at the rate of 30 fish/acre per year. If they can, then this may be doable.

**Bump**

GSH would also be good prey, they require no nest tending to reproduce. Their mouths are also to small to eat fingerling flathead. Ideally, the only predators of the young should be other flatheads.
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/19/19 05:30 PM

OK, Here is a study on 3 Michigan lakes where flathe... in Sand Lake).

Swingle determined that Flatheads heavily target 4" to 6" panfish. I guess this tends to persist even as they grow very large. The fish in the study above were much larger than I recommended. It would be better to match their stocking rates and fish sizes as it clearly worked. Flatheads live a long time, so they wouldn't need to reproduce if allowed to grow large
Posted by: canyoncreek

Re: Can flathead cats control crappie? - 08/19/19 08:33 PM

jpsdad, thanks for posting that link! You learn something new every day!

My wife's grandmother (96 yo) still has a cottage on Sand Lake and after years of not having a chance to go there, we were there for an evening of fishing a few weeks ago.

The lake association still is killing the weeds with chemicals every June, but another thing they did the last few years is they put in a LAKE WIDE aeration system. At least I assume the association is footing the bill... I've never heard of the DNR doing this..

But there are about 14 large air stations all around the lake and they run day and night in the summer. The water clarity and the removal of muck in the shallows is amazing. The water out to about 4' deep is back to pure sand (like it was in the good old days). I'm not sure if the natural springs have opened back up yet or not but I have to believe they are cutting down on muck in the deeper water too. It is an all around shallow lake with very few places deeper than 12' deep.

The locals say the bluegill fishing has dried up almost completely. Even hard to catch bass bigger than 14". I see from the PDF that they did plant catfish (that was a rumor I had heard before) but the report suggests no natural reproduction in their sampling.

Rarely someone catches a NP so they must not naturally reproduce so well either.

The graphs show very few pumpkinseed even. I'm wondering if the lake had gone through possibly some bad winterkills since it is so shallow.

But the evidence even in this tiny lake with a challenging environment for predator and prey shows that the hungry flatheads were cleaning up on small fish in the desired size range (less than 6")

Very fascinating read. Thanks!
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/19/19 11:01 PM

You are most welcome canyoncreek.

This topic piqued my interest. Flatheads are favorite of mine to eat. But when I catch one I tend to release it. I like them between 18 and 24 in. When they are bigger, I worry about mercury. Were it possible to set up a self sustaining population in 1 acre BOW where they are harvested at <4 lbs, I would be very, very, tempted to do that when I finally get around to owning my own BOW. One could probably grow some monster BG or WM in a BOW like that also. If there were some examples of it working with TP, GSH, BH, and/or red shiner, I would probably only stock a few male panfish a year as catch and release fishery and rely on TP and BH to feed the catfish.
Posted by: saint_abyssal

Re: Can flathead cats control crappie? - 08/19/19 11:33 PM

Originally Posted By: jpsdad
Were it possible to set up a self sustaining population in 1 acre BOW where they are harvested at <4 lbs, I would be very, very, tempted to do that when I finally get around to owning my own BOW.

Thanks for the PDF, I found it really informative and encouraging. Why wouldn't you be able to set up a self-sustaining flatty population? Do they not spawn in small BOWs? I thought their spawning was similar to channels'.
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/20/19 12:10 AM

Originally Posted By: saint_abyssal
Originally Posted By: jpsdad
Were it possible to set up a self sustaining population in 1 acre BOW where they are harvested at <4 lbs, I would be very, very, tempted to do that when I finally get around to owning my own BOW.

Thanks for the PDF, I found it really informative and encouraging. Why wouldn't you be able to set up a self-sustaining flatty population? Do they not spawn in small BOWs? I thought their spawning was similar to channels'.


It is and there is no doubt they will spawn, it deals with their survival after hatching ... the same is true of CC. If I were to do it, my goal would be harvest between 60 and 110 lbs of flatheads annually where none of them exceed 5 lbs and most are harvested at 2-3 lbs. There is no end to how big one can grow and if they resist harvest ... this scenario would fall apart over time where fewer fish of larger size dominate.

Flathead are really a stream and river fish and these generally don't build large panfish populations. Shad, carp, and other catfish are an important forage in these systems. There is also more habitat typically in those environments that protect young flathead. Even in these favorable conditions there isn't a lot of recruitment as these fish grow large and defend a territory. They can and do kill each other just defending a territory. Its a battle of attrition to reach 30+ lbs. They need room. In the paper above, the wildlife managers worked with these natural tendencies stocking at around 1.2 flathead per acre averaging ~10 lbs per fish. It was interesting that it still took three years to get the full effect. By then, they would have averaged almost twice the original average weight.

My suggestions were geared towards circumventing these tendencies where a larger number of sub-adult fish can co-habit the BOW. Harvesting most just as they reach sexual maturity ... before the territorial instincts really kick in. Was thinking some would still be able to spawn and if the forage didn't go about eating the fry they might reproduce as a self sustaining population where all fish are harvested before reaching 5 lbs. I can point to no examples that this is possible.
Posted by: ewest

Re: Can flathead cats control crappie? - 08/20/19 02:05 PM

Nice work. May write an article on that study.
Posted by: canyoncreek

Re: Can flathead cats control crappie? - 08/20/19 05:37 PM

ewest, if you do, please let us know. I got lost in some of the graphs and tables in that PDF. They spell out some of their conclusions about what worked and what didn't, but I bet a trained eye looking at the electrofishing information and the other tables could also extract some other very useful conclusions from the sand lake data.

I wish I knew if the DNR are still going out and sampling or have any interest in trying other active management strategies at that location. They have years of data now, and now there is a big new variable, the aeration and the improved water clarity. The predator prey balance is going to shift as the weeds go 'deeper' with better sunlight penetration and the water is clearer.
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/20/19 07:19 PM

Originally Posted By: canyoncreek


The locals say the bluegill fishing has dried up almost completely. Even hard to catch bass bigger than 14". I see from the PDF that they did plant catfish (that was a rumor I had heard before) but the report suggests no natural reproduction in their sampling.


There was data through 2014. One thing about Bluegills that I noticed was that number of BG smaller than 6" began increasing around 2000. Meanwhile the Pumpkinseed fell off the cliff. The increase of BG of that size might have in part been related to the space left by Pumpkin seeds. Notably lacking is any estimate of production (harvest counts and weights).

You have me wondering what happened to the BG between 2014 and 2019 when you were last there. Are they largely gone and if so why? Was the lake a victim of humans overharvesting, winterkill, or perhaps even the flathead. Next time you go, you should try to do some fishing for BG. If its anywhere as good as it was in 2014, then you would be in for a treat. Locals do have an incentive to underplay their good fortune if indeed they enjoy it. Where I am from, nobody tells the truth about where they catch their fish. The most popular reply is "Pinney Hill" and when you hear that you know they aren't saying! Or sometimes they say ... Right Here ... forming their index finger into a hook shape while indicating the fish were caught in the lip.

One thing I can say is that there is a huge difference between a trophy fishery (producing > 10" BG) and a good fishery (many 6" to 8" and few >8")when one talks about how fast the fishing is. Some prefer a lot of 6-8" fish and not a few 8-11" fish and this may be what they meant by "dried up". Sand Lake seemed to have evolved into a trophy lake with time ... at least until 2014.

Quote:
Rarely someone catches a NP so they must not naturally reproduce so well either.



They mentioned poor growth of NP in all the study lakes. Flathead presence did not help them.

Quote:
The graphs show very few pumpkinseed even. I'm wondering if the lake had gone through possibly some bad winterkills since it is so shallow.


The pumpkinseed were plentiful but too small to eat prior to the flathead introduction. The flathead were proceeding to extirpate them from Sand Lake. This tells me that BG are more robust and fecund. What we don't know is how the pumpkinseeds might have fared without competition from BG. It appears also that BH were greatly reduced in number by flathead presence.

Quote:
But the evidence even in this tiny lake with a challenging environment for predator and prey shows that the hungry flatheads were cleaning up on small fish in the desired size range (less than 6" )


Yes and I wouldn't have expected that.
Posted by: ewest

Re: Can flathead cats control crappie? - 08/21/19 01:22 PM

One thing I have learned over years of doing this - expect the unexpected.

Usually PS do not directly compete with BG. PS fill a different niche than BG much like the RES/BG combo. More likely that with lower reproduction and the same predator base (FH eating both and everything else) that #s of PS surviving to adulthood declined. In addition PS because they are smaller and live near the bottom stay both size and location wise in the FH bulls-eye more.

FYI

North American Journal of Fisheries Management
Article: pp. 198–202

Gape:Body Size Relationship of Flathead Catfish
Joe E. Slaughter IVa,,1 and Brad Jacobsonb
a) Georgia Department of Natural Resources, Wildlife Resources Division, 2065 U.S. Highway 278 SE, Social Circle, Georgia 30025, USA
b) Arizona Game and Fish Department, Region IV, 9140 East 28th Street, Yuma, Arizona 85365, USA

Abstract.

The flathead catfish Pylodictis olivaris is a highly piscivorous ictalurid native to central North America whose range has been extended throughout much of the United States. With this range expansion, many populations of native fishes have experienced declines in the number of individuals due to direct predation by flathead catfish. Previous evidence suggests that flathead catfish are opportunistic feeders and may be the least gape limited of North American freshwater piscivores. To better understand the size of prey vulnerable to flathead catfish, we measured gape dimensions for individuals of various sizes to determine the maximum size prey a flathead catfish can kill based on its gape limitations. Our results show the relationship of total length to horizontal and vertical gape and the relationship of flathead catfish total length to the total lengths of ingestible-sized prey of different body shapes. Furthermore, comparisons of the body depth of three common fish species to the gape dimensions showed that no size of largemouth bass Micropterus salmoides, bluegill Lepomis macrochirus, or gizzard shad Dorosoma cepedianum would preclude predation by flathead catfish. Our results support the assumption that the flathead catfish is one of the least gape-limited piscivores.

Received: January 31, 2006; Accepted: May 4, 2007; Published Online: February 11, 2008

DOI: 10.1577/M06-033.1
North American Journal of Fisheries Management 2008;28:198–202
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/21/19 04:38 PM

Quote:
PS fill a different niche than BG much like the RES/BG combo. More likely that with lower reproduction and the same predator base (FH eating both and everything else) that #s of PS surviving to adulthood declined. In addition PS because they are smaller and live near the bottom stay both size and location wise in the FH bulls-eye more.


I totally agree with this. Resources for both PKS and BG were not as limiting as they were before the FH introduction. After the FH introduction there was plenty of food to go around for both PKS and BG. That said they used that food and probably together attained Fall standing weights that were a high proportion (though a ratio of less than 1)of their standing weights prior to the introduction of flatheads.

The point I was making was that the abundance of less than 6" bluegill increased considerably from 2000 to 2014 in electrofishing surveys. Why did the number of BG less than 6" increase in number from 2000 to 2014? It seems plausible that BG were able to use some of the resources that were earlier utilized by Pumpkinseeds. This is debatable, what do you think most influenced the production of less than 6" BG during this period?

As to question how would Pumpkinseeds fared in the absence of BG, it may well be that they would have been on a path of extirpation.

It should be noted that the use of FH as they did it was a REMEDIATION of overpopulation conditions where standard predators utterly failed to control the BG and PKS. Growth rates of younger age classes of predators would have also have been weak as these youngsters were competing with BG, PKS, and crappie for food. These lakes were a lost cause and the FH, no matter how you shake the mustard, made an impossible situation a great panfish fishery. It was able to accomplish tangible benefits by the third year and with no extra management, provided an excellent environment for the production of large panfish for a minimum of 20 years.

There are many lessons to be learned here but one shouldn't think that FH can help every fishery. Those with existing excellent panfish fisheries might and probably would be harmed by their introduction.
Posted by: Shorty

Re: Can flathead cats control crappie? - 08/21/19 07:30 PM

We have an 1800 acre lake 10 miles from me that has been extensively stocked with FHC and wipers to control an accidental introduction of white perch. Branched Oak lake also has gizzard shad and the FHC are under total catch and release regulations. There are still lots of 5-6" stunted white perch in the lake. Stripers we're stocked several years ago to no avail, it is however a fantastic FHC lake.

http://magazine.outdoornebraska.gov/2013/06/branched-oak-flatheads/
Posted by: RStringer

Re: Can flathead cats control crappie? - 08/22/19 07:17 AM

That's a pretty cool story. We have them in our rivers here in Kansas. Those are some monster fish.
Posted by: canyoncreek

Re: Can flathead cats control crappie? - 08/22/19 11:04 AM

ewest, if you need more info or pictures of sand lake for your article I can try to help you.

jpsdad, I can tell you that the fishing for 6" plus panfish MAY have been better at some point in the last couple of years but the locals have not seen any change. For sure in the past 2-3 summers there seems to be zero decent BG or PS of any type. Hard to even catch a stunted one. Nephew and 2 buddies spent a couple hours fishing with worms and had only about 5-6 stunted ones to show for it.

I do not know that they run the aerators in the winter (I can find out but I that was not mentioned to me) Winter kill is a possibility.

The word on the lake is that they don't catch any catfish either so I'm thinking the original stockers are gone or are few and there was no natural reproduction.

The water is very very clear now and much less weeds in the shallows. To me the lack of weeds is surprising with the aeration. To me that means that the aggressive use of weed control chemicals also changed the refuge that the small fish use in the weeds.

Agree that in the last decade the lake probably continues to get shallower and that makes it a less favorable place for NP.

Per Mr. Cody, pickerel are better suited for warmer shallow lakes, I wonder why in the many small, eutrophic puddles around my house that they don't try to use CP for additional predator influence beyond the typical LMB?

I also wonder why the DNR wouldn't try to boost the forage base in many of these lakes using GSH or other shiners such as spotfins?

But the point of this thread is that catfish can really exert an immediate and measurable effect on certain slot size of panfish.
Posted by: ewest

Re: Can flathead cats control crappie? - 08/22/19 01:15 PM

Originally Posted By: jpsdad


ewest in red

The point I was making was that the abundance of less than 6" bluegill increased considerably from 2000 to 2014 in electrofishing surveys. Why did the number of BG less than 6" increase in number from 2000 to 2014? ... what do you think most influenced the production of less than 6" BG during this period?

Improving condition of BG status resulted in many more BG being hatched and those were not the prime FH food source (to small at the beginning). Result many more small BG. Also electro surveys are not always unbiased - they are a tool not an answer.

As to question how would Pumpkinseeds fared in the absence of BG, it may well be that they would have been on a path of extirpation.

Very likely that FH could consume more PS than the PS could reproduce. This has been documented in BG only ponds after the intro of FH. In a few years BG were almost impossible to catch as they had mostly been exterminated.

It should be noted that the use of FH as they did it was a REMEDIATION of overpopulation conditions where standard predators utterly failed to control the BG and PKS. Growth rates of younger age classes of predators would have also have been weak as these youngsters were competing with BG, PKS, and crappie for food. These lakes were a lost cause and the FH, no matter how you shake the mustard, made an impossible situation a great panfish fishery. It was able to accomplish tangible benefits by the third year and with no extra management, provided an excellent environment for the production of large panfish for a minimum of 20 years.

There are many lessons to be learned here but one shouldn't think that FH can help every fishery. Those with existing excellent panfish fisheries might and probably would be harmed by their introduction.
Agree on last para.


Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/22/19 05:05 PM

Quote:

Very likely that FH could consume more PS than the PS could reproduce. This has been documented in BG only ponds after the intro of FH. In a few years BG were almost impossible to catch as they had mostly been exterminated.


By the time a flathead reaches 5lbs, it is a creature that wants to grow 3 to 4 lbs per year. At the lower growth we are talking a 30 pounds of forage for growth and 25 pounds for maintenance and so roughly 55 pounds for the 5# spring flathead. With a 20 lb flathead we are talking 130 lbs of forage. This tells me that more than 25 lbs of flathead/acre will stress the production limits of many BOWs. Sand Lake was considered borderline eutrophic and it isn't clear what weight of forage it was capable of producing. Even so, it seems plausible to me that the flatheads' needs ultimately reached the prey production limit at Sand Lake.

LMB do that to, all the time when you think about. The answer to that problem is a fish harvest and from a management perspective, the same applies where FH are used to control BG overpopulations. A regular stocking FH of a starter size (say 5 lbs) and harvest of minimum length FH would prevent the FH from attaining to large a mass.

Quote:
Improving condition of BG status resulted in many more BG being hatched and those were not the prime FH food source (to small at the beginning).


There are theories that predators prefer the biggest prey they can stuff in their mouth but these theories have never been supported by evidence. We know they are limited by gape but this limit has never been shown to be what they prefer nor what they tend to eat. With increasing gape there is a tendency to eat larger prey and that ... when you think about it ... is just because they can. There is a preponderance of evidence that suggests that piscivorous predators tend to eat prey at about 1% their body weight. A flathead is going to take any opportunity it gets, however, if it is close enough to suck in a 3" fish it is going to do it without worrying about whether it expended too much energy opening its mouth.

IMO the larger BG are most at risk when the production of 0 through 2 year BG are no longer capable of sustaining and growing FH Biomass
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/22/19 06:38 PM

Originally Posted By: Shorty
We have an 1800 acre lake 10 miles from me that has been extensively stocked with FHC and wipers to control an accidental introduction of white perch. Branched Oak lake also has gizzard shad and the FHC are under total catch and release regulations. There are still lots of 5-6" stunted white perch in the lake. Stripers we're stocked several years ago to no avail, it is however a fantastic FHC lake.

http://magazine.outdoornebraska.gov/2013/06/branched-oak-flatheads/


Shorty, I've spent quite a lot of time last night reading up on Branched Oak. The FH reproduce there and are not harvested so I guess they are just unable to reach the biomass that might control the white perch. There are a lot of other predators in the lake as well. It must produce a huge weight of white perch annually small though they are.

I could find no reference to how they got there. Every state has its conspiracy theories about wildlife biologist gone mad ... does one exist about white perch?
Posted by: Shorty

Re: Can flathead cats control crappie? - 08/22/19 07:28 PM

White perch were accidentally introduced by one of our State fish hatcheries. The presence of shad compound the white perch problem as predators prefer eating shad over spiny white perch.

https://www.fws.gov/fisheries/ans/erss/highrisk/Morone-americana-WEB-7-30-2014.pdf

Quote:
“White perch was brought from New Jersey to Nebraska in 1964, and fry produced that year in a hatchery were accidentally introduced into a reservoir that provided access to the Missouri River (Hergenrader and Bliss 1971).


Quote:
Walleye or White Bass eggs can make up 100% of White Perch diet depending on which fish is spawning. During a three-year study, this diet was found to be unique in that: 1) eggs were eaten for a comparatively long time, 2) they were the only significant food item eaten by adults during two of the three years, 3) large volumes were eaten per individual, and 4) most fish were feeding. White Perch also feeds heavily on minnows Notropis spp


Quote:
“Within three years after being introduced into a Nebraska reservoir, White Perch had completely replaced the previously dominant Black Bullhead Ameiurus melas. Species composition changed from 74 percent Black Bullhead to 70 percent White Perch in that
time frame (Hergenrader and Bliss 1971).”
Posted by: Shorty

Re: Can flathead cats control crappie? - 08/22/19 07:34 PM

Big FHC can be territorial, guess what made these marks?



An old link.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=71588

Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/22/19 08:04 PM

Thank you for the info Shorty. That's a mighty fine FH and there is no mistake where that bite mark came from!
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/23/19 05:07 PM

Saint, so you might be able to have cake and eat it to.

To be successful you want to harvest the flathead so that the requirements for growth and maintenance do not breach the BOWs potential production. Actually, it should be below this in order to allow you to harvest some crappie. Ideally the weight at which they are harvested will correspond to multiple of 100 times the weight of crappie you want the FH to crop. For example, if you want FH to do the cropping up to 8" length for the crappie (.25 lbs) then you should crop the Flathead before or around 25 lbs in weight (38 inches). For a 6" length of crappie it would be FH of 10 lbs(28 inches).

If FH are unable to reproduce in the BOW then you can make fairly reliable estimates of how much the FH weigh and will gain. If you fish for them and fin clip so that you may identify individuals ... then you can gain keen insight by tracking their progress. Combined with your crappie creel you can establish understanding of your BOW's production capabilities and be able to fine tune your management of predators. There should be an additional prey species that is not inclined to eat crappie or compete with the crappie without providing substantial crappie forage. Its presence will feed crappie and take some predation off the crappie, GSH might be a good choice or perhaps TP if they are legal in your state.

If the FH reproduce then your only recourse is to monitor the crappie. Harvest any FH that exceeds 100 times the weight of the largest crappie you want to be cropped by flat head. If you don't get good crappie recruitment above this weight of crappie, then you might need to reduce some FH below that target weight. To be a good crappie BOW, they need to pull off some good spawns and hopefully this occurs on a yearly basis.

It still seems quite a challenge to source the Flathead if they don't reproduce. On the other hand, if they do reproduce they might very quickly attain too high a biomass. The best situation would be where you can ladder stock flathead ideally from a reputable aquaculturist and the flathead fail to recruit. Under this scenario you would have a great handle of the FH biomass and size structure.
Posted by: saint_abyssal

Re: Can flathead cats control crappie? - 08/25/19 04:53 PM

Originally Posted By: jpsdad
There should be an additional prey species that is not inclined to eat crappie or compete with the crappie without providing substantial crappie forage. Its presence will feed crappie and take some predation off the crappie, GSH might be a good choice or perhaps TP if they are legal in your state.

What about YP instead of tilapia?
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/25/19 07:02 PM

I don't see why you couldn't approach it from this angle. I would just say that GSH and TP are able to convert primary algae production DIRECTLY which is particularly why I recommended them. In other words, they will certainly produce more forage than YP because they won't depend entirely on secondary trophic organisms for food. The YP in the sense that they will feed on similar food of the crappie will compete to some degree with them. Even so, I consider crappie the stronger species and I think FH will predominately prey on the YP. Having YP instead of the other choices may mean that you need to be more sparing on the FH biomass. This said, with the right balance it could perform very well I think. With regard to TP as a tertiary harvested fish, particularly mossambica is most catchable and they could be also be harvested by rod and reel.
Posted by: Augie

Re: Can flathead cats control crappie? - 08/26/19 10:04 AM

FWIW, it's not at all unusual to catch 5lb size flathead catfish on 6" bluegill while fishing the Missouri River.
Posted by: jpsdad

Re: Can flathead cats control crappie? - 08/26/19 05:05 PM

Augie, I know that to be the case. Question then is what do flathead of that size most commonly eat. There is a lot of data that supports that predators most commonly eat prey at about 18.8% their own length. Across a broad range of predators, albeit I haven't seen data on flat head, this holds true and across many different age classes. Where there is exception it goes the way of smaller prey, for example, Muskellenge which tend to eat prey that is a smaller percentage of their length as they grow bigger. Now they eat larger prey for sure, but the relative size does tend to decrease as they get larger.

The way to look at this is that there is a distribution of prey size and when you look at a frequency plot, the curve is consistent with a probability function. 70% of the prey will fall within .75% and 1.33% the weight of the predator. Some do fall outside this range and when they are attached to a hook, there is little the prey can do to avoid being eaten.

I admit that I can not fully explain this but if I had to venture a hypothesis it would be this. Fish growth tends to be allometric. This means that they tend to grow proportionately in 3 dimensions. What this means is that fish's mouth volume and the volume of water it can engulf when launching an attack is proportionate to its weight. The 1% prey size might represent the optimum prey where the failure of capture and energy gained strike the optimum balance. The lower limit is around .1% or around 10% the length of the predator the upper limit seems to be the limit determined by gape.

From a management perspective, one should plan for the most probable outcomes. If one desires the diet to be primarily 6" prey, then one wants to be sure the predator is large enough to predominately prey on prey that large.