(Click Photo to Enlarge) According to Samuel Eddy's guide to freshwater fishes, the final determining difference between white and black crappie is based up the distance from the eye to the dorsal fin.
There is always great debate in fishing boats far and wide… is it a black crappie or is it a white crappie?
The majority of anglers try to make their identifications based on body color. A "scientific" angler won't fall into that trap, with any fish species.
Colors vary widely for black and white crappie, depending upon water clarity, season and especially spawning conditions.
A man named Samuel Eddy wrote the fish identification key that the majority of biologists subscribe to. According to Eddy, the final determination between a black and white crappie is as follows:
White crappie (Pomoxis annularis): the distance from the eye to the front of the dorsal fin base is GREATER than the base of the dorsal fin.
Black crappie (Pomoxis nigromaculatus): the distance from the eye to the front of the dorsal fin base is about EQUAL to the base of the dorsal fin.
Other clues include the number of spiny dorsal rays (the hard, sharp rays). A black crappie will typically have seven or eight spines. A white crappie will typically have five or six spiny rays in the dorsal fin.
In Chickamauga Lake the majority of crappie are white crappie, although black crappie are caught frequently. The state record white crappie weighed 5 lbs. 1 oz, taken from a private lake in 1968. The state record black crappie weighed 4 lbs. 4 ozs., taken from Brown's Creek Lake, a state-operated lake in 1985.