Too many small crappie in Patoka Lake
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Originally Posted by
wannabe fisherman
yep too many of'em they don't grow much and need to be thinned out :Rofl
Had a game warden that checked me once tell me not to throw the small ones back. He said to throw them on the bank if we didn't want to keep'em
That's interesting and is what I heard from one of the fishery people at IDNR somewhere. When you have so many crappies and they have very slow growth rates it means that there is not enough food to feed them all. If you can't give them more food then thin them out. The Gizzard shad are only small enough for the smaller crappie to eat for a short period of time. And the Gizzard Shad grow too big for the smaller crappie to eat. The smaller crappie starts out on small insect aquatic and terrestrial and then eat smaller fry and minnows. Evidently, Patoka Lake doesn't have enough food for these crappies to grow bigger You have to wade through a lot of 7 to 8-inch long crappie before you can find the bigger ones.
Small pond water volume vs Patoka Lake water Volume
Quote:
Originally Posted by
wannabe fisherman
when I had a small garden pond the people at the pond store told me if I wanted my fish to grow to their full size to change the water by about 1/3rd every year. Said the fish emit some kind of enzyme that will stunt their growth. I wonder if that could have anything to do with small fish also. I know there's flow in a lake but still, I wonder about it.
Not sure about fish enzymes but fish do poop and pee and the nitrates that they emit can accumulate to high levels in a small coy pond or an aquarium. Patoka Lakes water volume and diverse ecosystem can take up the nitrates from the fish and use it as food. The nitrogen cycle is taught in schools. Nitrogen is a limiting nutrient and is recycled through the food chain. There are nitrogen-fixing bacteria that can use the fish poop as their own food. That's not the case in a small pond with a plastic liner. This is why you have plants in the coy ponds. The plants can take up the nitrogen and use it for food. There must be a balance in the ecosystem of the pond.
Keep a few of the small crappie and examine them to see what they are eating. Cut them open and examine the stomach contents. These small crappies are not able to open their mouths (gullets) large enough to eat a big shad. Now if Patoka had Threadfin shad instead of Giggard Shad the crappie would be able to grow much faster as the threadfin shad are smaller in size and can be eaten easier by smaller crappie and larger crappie.
Gizzard shad can grow to up to 18" in length and that's hard for a small crappie to eat.
Again I'm not sure about what enzymes he's talking about. Weird things happen to mammal populations when they get too large. But fish live in schools according to age size. They probably run out of food before anything else. The carrying capacity of the lake area limits the fish population and size distribution of the fish.