Carroll County Times
Carroll County Sports

Jim Gronaw: How old is that fish? | OUTDOORS COMMENTARY

This 16 1/2-inch black crappie caught earlier this month may well have been at least 12 years old. Many factors determine growth rates and top-end size of fish.

Over the years there has been much research and study devoted to the aging process and evolution of various species of fish by both the scientific community and amateur biologists alike. Often, the studies are done on the “headline” species such as bass, trout or stripers. In recent years biologists have devoted some of these efforts into determining the age of various panfish species like crappies, bluegills and yellow perch.

With conservation efforts finally coming to the forefront of the panfish community, more and more anglers are starting to release trophy-class panfish, not keep their daily limit and educate themselves as to what can be done to improve panfishing waters that have suffered from years of overharvest.


Fishery biologists continue to use the standard scale samplings from various sized fish that exhibit yearly annuli rings on scales, indicating a span of increased growth during warmer months and a period of stagnant, or no growth during colder, winter months when feeding activity is at it’s lowest. Under a low power microscope, a scale with four annuli rings would indicate a four-year period of growth, or a 4-year-old fish.

Some biologists feel the initial annuli ring during the fish’s young-of-the-year stages may not be present from its birth year, making it a year older than the ring count. Regardless, the scale samples give us a pretty good idea of the approximate age of most species of fish caught in regions where seasonal changes in weather and environment occur.


Many factors come into play determining the top-end size and health of a specie of fish in any given body of water. To produce large, trophy-class fish there needs to be a variety of components during the fish’s early “growth” years. Water quality has to be good — no pollutants, low-dissolved oxygen or parasitic concerns. Abundant, high protein forage (minnows, shad, zooplankton or insect varieties) need to be available to the fish throughout its growing years. Young panfish and bass feed primarily on insect larva the first few years of their life, transitioning to larger insects, crustaceans or smaller minnow species as they age and grow. During those “teenage” years, fish need larger prey to get bigger. Crappies will take YOY bass and bluegills or shad species. Bass will feed on mid-sized panfish, shad and adult crayfish. As they age and get to trophy size, they may be forced to feed on the most abundant food source, whatever the case.

In the Mid-Atlantic region, one can safely set the bar on trophy class fish of a variety of species. Largemouth bass, for example, generally top out at around the 24-inch mark — a very rare fish in all but the most special of waters. The odds of a bass reaching such a length in our region are astronomical, yet achievable, in prime lakes and ponds where ideal conditions prevail. A true giant of a crappie would be in the 17-inch category and a legitimate 12-inch bluegill is a fish that few of us will ever see in a lifetime. Yes, all of these fish, and larger, do occur in Maryland waters, but not to the routine.

Perhaps the “X-factor” in all this is the genetics of the fish as scientists are now discovering that certain genetic qualities are passed from one generation to the next in larger, adult fish. When genetics are removed either by natural disasters or continual harvest, rebuilding of superior genetic qualities is stunted, slowed or even completely halted as in the case of trophy-class bluegill that exceed 10-inches. Of bass, crappies and bluegills, the bluegill is the one most likely to suffer from overharvest issues. Additionally, the smaller the body of water, the more likely angling pressure can alter top-end size structure.

A recent study was conducted on Mississippi waters of Grenada Lake where the population of huge white crappies were aged through scale sampling. Historically, Grenada, Arkabutla, Sardis and other huge reservoirs of the region routinely yield crappies in the 2½ to 3½-pound range, giants by any man’s measure. It was discovered that a 2-year-old crappie averages 12-inches in length and a 3-year-old fish goes 13½ inches. These are astonishing growth rates and the great majority of 5- and 6-year-old crappies are 16-inches plus and in excess of 3 pounds — the benchmark for a world-class crappie. It is also noted that after the sixth-year growth slows considerably. Literally, these fish are out of the blocks fast and hard with few fish living longer than eight years.

Surprisingly, the recently discovered black crappie populations in central Maine boast trophy, northern fish that reach the 16-inch mark, but with slow growth and brutal winters, they are very old fish that are reportedly in the 12 to even 15-year-old class. These are very old, very slow growing crappies that have been received as a “non-native invasive” species and are often thrown on the ice by local ice fishermen to rot or be eaten by eagles. Both local and vacationing anglers are now trying to get statewide authorities to install some type of creel and size regulations to preserve this sensational rare panfish fishery of trophy class black crappies that has quietly evolved over the past 25 years.

In our local waters, I have always thought that it took at least 10-years to grow a trophy-class fish in their natural state. Some would grow quicker and other more slowly. Forage is a huge factor in top end size structure and a potential record-class fish could possibly be harvested early in its life for the sake of a fish sandwich. In a lifetime of fishing, I have caught only a handful of crappies exceeding 16 inches and none over the 17-inch standard. I had always figured those fish to be a dozen years old, if not more. In those diverse and world-class fisheries like Grenada and Maine, the fish get huge based on many factors and the preservation of these fisheries are worthy endeavors. Think about it, how old is that big fish you just caught?