james holt, unless we caught every fish in the lake, we can't be sure about what has successfully reproduced. I've had problems with my knees all of last summer but normally we have at least 3-4 groups a week fishing our lake. Each group will catch 50-100 fish so we're looking at a large percentage of the fish. Also we fin clip everything so we can tell what we stocked and the fish that we have sampled. We only let people fish from two places. Every so often, a friend and I fish other parts of the lake to see what is there. At the end of a summer, about half of the fish we catch have been caught before.
We use fathead minnows for bait which catch certain species. Every so often we will use worms, leeches, crawfish or frogs to catch other species.
Obviously, this isn't exact but Dave Willis has some of his students sample the lake every two years which adds to our knowledge.
The point of this is that we do a lot of sampling in many different ways. You'll find this in many posts. Keep track of what you are catching, fish many different ways and keep good records. In the long run, you will have a very good idea about what is happening in your lake.
