White crappie generally grow faster than black crappie, but the specific environment has an overriding effect on fish growth, even between neighboring ponds. Availability of food, water quality, depth, and other factors will all contribute to growth rates of either type of fish. In fact, the region of the country may have the strongest effect of all, with northern states seeing slower growth (probably due to the long, cold winters) and southern states boasting significantly larger fish of the same age. If you’re curious and want to estimate the age of your recent catch, crappies can be classified by counting their dorsal spines: white will have 5 or 6 while a black crappie will sport 7 or 8 spines.
In a very broad way, it’s considered reasonable to say that the size in inches of mature black crappie is generally equivalent to its age in years. For example, a typical 14” specimen will be around 14 years old and weigh roughly 1.7 lbs. A white crappie of the same size will weigh in slightly less at 1.4lbs but will generally be just about 9 years old. However, northern anglers rarely report even seeing crappie in the 15-17” range. In contrast, anglers in the southern states estimate that in a fertile pond with little competition and no overpopulation, a healthy black crappie might reach 14” in only 5-6 years. It’s interesting to note that there have been few formal comparative studies conducted on growth rates for crappie across regions, so reliable comparisons are difficult to make. If you’ve caught a large crappie and are curious about your specimen’s exact seniority, it’s not difficult to determine the age by counting the rings on one of its scales - scales grow much like trees and reflect annual growth patterns. An excellent description of the information about a fish’s personal history stored in its scales can be found on the website of the Delaware Division of Fish and Wildlife (http://www.dnrec.delaware.gov/fw/Fisheries/Documents/agegrowth.pdf)