Looking for some feedback on gizzard shad and advice on what to do. We have a 25 acre lake that is highly fertile. We have a large rookery in the area and regularly have to run birds out to other parts of the property to keep them from roosting in the trees in our fishing lake. If we aren't careful we can quickly have tens of thousand of herons, egrets, ibis, etc. setting up shop in our stocked lake. In addition to the birds, approximately half of the lake is covered with cypress trees. We also have duckweed with varying degrees of coverage depending on wind and water fertility from birds. We have removed a couple hundred trees but there are still hundreds of trees that create a closed canopy over about half of the lake.

We have installed a large paddle wheel aerator (good for about 12 acres) and have a DO meter to check oxygen levels when needed. I have some aquaculture/fisheries experience and a degree in wildlife and fisheries so I have a decent idea of how things work.

The lake was drained and reworked (trenches, etc) and stocked 2 years ago with LMB, HSB, CNBG, RES, TFS and FHM. After stocking we experienced a problem with our drain pipe and the neighboring bayou backfed into the lake on several high water events. As a result we inherited white crappie (WCP), bullhead catfish (BH) golden shiner (GSH), gizzard shad (GSD), green sunfish (GSF) and probably some other unwelcomed species. I recently cast netted several large GSD that were in the process of spawning.

I have done quiet a bit of reading on other sites as well as old PB threads in an attempt to better educate myself on how to manage our current situation. We have heavy algal blooms so my initial thought was that we had unlimited food for the shad. The plan was and may still be to let the bass do their thing without removing any for at least the first 3 or 4 years to see if they can make a dent in all this food. I'm a little worried that the GSH may eat all of the larger zooplankton that our young CNBG and other fish will need. When we stocked we went with, 3/4 of the bass being F1 LMB and the other 1/4 were straight Florida LMB. We are catching some really healthy LMB and HSB but they are sometimes hard to catch or find, I'm assuming this is because they are loaded with shad, etc. and aren't hungry. Would we be asking for trouble if we didn't take out bass for another year or two? Should I consider trying to remove some the larger shad by shocking, netting, etc? Any thoughts or advise on how best to proceed would be greatly appreciated.

Thanks,
Ben

Ben I don't have much experience managing southern waters, but up here the Gizzards can grow faster to adult size that are bigger than the LMB can eat in a year, maybe two years. Some public lakes here have a low dose of Rotenone applied that is low enough to kill the Gizzards but not any of the other fish.

Typically Gizzards aren't stocked until at least 25% of the adult LMB in the pond can eat the adult GSD.

Esshup,
Thank you for your feedback. What do you think about not harvesting any LMB for several more years to let them work on the GSD numbers. We stocked two years ago and are catching different sized LMB that look good. Some fish are in the 4 pound range.

As one creates a thriving food rich ecosystem,,, land based predators soon learn there is a bountiful buffet available. Nature's Law. Keep doing your best to deter them as much as practical.

Initially I am agreeing with BeSaDo's thoughts, that it is a good idea to allow the LMB and HSB populations to develop at least another year or even two more years until the initial stocker year class of bass commonly reach the 5 to 7 pound sizes. They then can prey of the 10"-12" GSD.

With your now unplanned introduction of high diversity of 'trash' fishes this is a positive and negative. Positive in that it results in a lot more types of food forage items and a negative it results in more difficultly in managing more species for the 'juggling' of fishery balance. IMO these added trash fishes makes managing the lake more difficult for creating trophy bass (10lb+) because now ideally, you want lots of predation pressure from smaller bass (12"-16") present to effectively control the numerous offspring and young species of the less than desirable forage species.

If it were mine, I would educate and teach the membership about the complexity of the current fishery balance problem, emphasize the positives and encourage them to be happy with catching more numbers per hour of the more aggressive angler friendly 5lb-8lb bass compared to a lot of days angling and catching very few of the 10+lb LMbass. This is mainly because there are always a lot more younger bass than the oldest bass. More numbers almost always means higher angler catch rates.

Also In a couple years as the HSB grow to larger 7lb - 10lb sizes these freight train pulling HSB will also help the angler membership catch more very good quality fish during each fishing experience. Often catching HSB requires using slightly different methods that the anglers may need to learn about for frequently catching bigger sizes of both HSB and LMB.

The other thing that I would routinely do is get the lake electro-fished once or twice a year to help monitor the balance of the fishery. You do not want the fishery to get out of balance for the ESTABLISHED goals. When out of balance, a 20 ac lake is very costly and time consuming to return it to the desired balance. Example - look at the cost now of your "out of balance" lake again that needs renovation because it has been invaded by the allotment of new species causing balance problems. Electroshocking effectively monitors the balance and numbers of a large number of fish species. FYI - two types of electroshocking methods are available DC and AC. Each has it benefits - learn the pros and cons of each method and use them appropriately for the species that you want most sampled.

The second thing that I would suggest if to routinely add HSB because they do not reproduce each year to add more young, efficient, open water predators to help control GSD and young open water crappie which need high pressure predation to keep undesirables reduced. LMB are good littoral predators and HSB are good open water perdators.

Hopefully mentor B.Lusk and other experienced managers will visit this thread soon to get his opinions. Keep checking back for new opinions.

How many and what size LMB did you stock per acre ?

Your Number One problem will be water quality. I've worked on several south Louisiana lakes over the years and that's been the biggest nemesis. With so many birds depositing so much waste, even with gizzard shad rooting around on the bottom, input will far exceed your ability to get rid of it. If you have a good well, flushing water will be important. Constantly watch your water quality by measuring visibility, being on the lookout for toxic amounts of blue-green algae in the summer and even in the winter. Aerate and move the water as much as possible. The second issue will be managing the fishery, as discussed to some extent above. I'd look at getting threadfin shad as well. Gizzard shad feed on the bottom, threadfins are filter feeders. Also, if the lake has enough depth, look at getting a few paddlefish. They can help by consuming large amounts of plankton.
As mentioned above, predators will also be an issue.
Diligence is important on several levels in Louisiana.

I agree with both Bill and Bob. Water quality will be a huge issue with all the nutrients that the birds add. Electroshocking will be an important fishery monitoring system.

Especially with your HSB as your possible low DO and hot temps will stress them.

Thank you all for the feedback, it is very much appreciated and gives us confidence that we know what needs to be done with our lake. I'm really looking forward to any additional feedback or experience other pond managers and lake owners may have had with similar lakes/issues. It's always good to hear what has worked and what the latest data can show us.

Ewest, in 2/2021 we stocked 9000 CNBG, 3500 RES, 10,000 FHM, 1 load of TFS (can't remember how many fish that was approximately). In 6/2021 we stocked 1000 2" F1 LMB and 150 2" Florida Bass, and in 7/2021 we stocked 2000 4-5" HSB.

I think it would be awesome to add some paddlefish. When I was working as a research associate in aquaculture we had paddlefish in some of our ponds. I think they came from our state hatchery which I believe no longer sells to the public. Do any hatcheries currently sell paddlefish? I've never seen them listed by anyone.

I thought the TFS and GSH would help consume large amounts of plankton. I asked an old coworker/county agent and his response was "once a bass eats a shad and digests it...the nutrients are right back in the lake". I'm assuming there's some conversion of nutrients into fish tissue however he didn't seem to think it was a good option unless I could somehow remove the larger shad from the lake.

We definitely have some wild blooms that I have to monitor closely. Luckily we haven't had any blue green blooms...knock on wood. I live close to the lake and can check it daily when I'm not away for work. Our big paddlewheel aerator should be good for about 12 acres (the front of the lake with only a few trees). We had to run it for a couple of weeks last summer when our bloom died. My only concern is that when we run it, seems to eliminate the thermocline. It held the lake DO at about 4 ppm but that's a little close for comfort IMO. The birds are out this year so hopefully that won't be a problem that adds to our nutrient loading.

Do they need to try to have a lake rule of not deliberately fishing for HSB when the water temps are elevated?

I thought a paddlewheel aerator was LESS likely to eliminate the thermocline?

That's the rule at my place when water temps climb much above 80. Even with good DO.

Lots of threads here on HBS, fishing and heat/low DO negative effects.

With a lake that size a electrofishing survey would be a wise move. Also learn how to do a seine survey.

I never noticed a reply on paddlefish. Anyone know of a paddlefish producer? Thanks to everyone who provided feedback on the gizzard shad in fertile lake issue! I also learned that when the water temps are in the mid 70's and up, HSB don't handle catch and release very well. In all of my reading on HSB I never came across that! As usual, lots to learn from PB!

Osage Catfisheries handles paddlefish.

No idea if they can be legally transported from Misery to Lousiana.

Osage Catfisheries paddlefish