No single person is going to make or break a species with the amount he/she keeps. As long as they stay within the legal limits, that is. That's what the limits are for. Your local biologists know how many need to be kept/released, and that's the info they use to set the limits. This question is best suited for a small unregulated body of water like a private pond. But lakes are huge, and nearly impossible to overpopulate. JMHO
Jeremiah 16:16a "But now I will send for many fishermen," declares the Lord, "and they will catch them."