i dont keep near as many as some people that i fish with. that may be because i only eat fish when they were caught the same day. dont know why thats just me. but back to ur question, i believe that the crappie are so plentiful and reproduce in such large numbers that (in the waters i fish anyway) that it doesnt hurt anything to keep as many as is legal. thats why they have limits on number and size. if the biologists thought it would hurt the population they would change the regulations. thats just the way i look at it.