How Old Do Flathead Catfish Get? by Don Orth

The recent catch of a 62-pound Flathead Catfish from the upper New River was a rarity and generated many questions.  One of these was "how old is this fish?"    Fortunately, I can answer that question, thanks to Timmy Dixon who provided me with the head.  With the help of annual rings laid down on the ear stones (i.e., otoliths) of the catfish, we can determine its age. It's not possible to estimate the age of a Flathead Catfish from it's weight alone.  There is just too much variation in growth rates among individuals.  

Lapillus ear stone from 62 pound Flathead Catfish glued to glass slide.  Lincoln penny for size reference.
 Photo by Cobin Hilling.

Otoliths are calcareous accretions that permit detection of sounds and maintenance of  equilibrium via the semicircular canals. Because the grow continuously as the fish grows and grow faster when the fish is actively growing, annual rings are discernible.   The otoliths of the Flathead Catfish are tiny compared to the size of the fish and can be a challenge to find.  There are three pairs of otoliths -- asterisci, lapilli and sagittae.  To learn how otoliths are removed from large catfish, check out this post.  In this Flathead Catfish, Corbin Hilling extracted the lapillus (above), which is the largest otolith in catfish. 

Otolith section from 62 pound Flathead Catfish.  Photo by Corbin Hilling.

In order to count all the rings, the otolith is sanded until all the rings from the nucleus to the edge can be seen.   In this otolith section, Corbin Hilling counted 25 annual rings. So the Flathead Catfish was born in 1994. The maximum age from populations of Flathead Catfish averages about 20 years and the oldest individual aged was 32 years old (Massie et al. 2018).  

Once Flathead Catfish reach about 30 inches (or ~ 75 cm), they begin to develop massive girth. To reach a 25 pound trophy mark, Flathead Catfish have to survive to at least 7 or 8 years. Once they reach that size, they have must eat a lot to grow larger and are highly vulnerable to hook-and-line or trotline fishing.   The 62 pound Flathead Catfish is clearly off the chart showing weight attained at different ages (below).

Weight of Flathead Catfish by age (years) from the James River from Hilling et al. (in press).

The Flathead Catfish was a rare trophy catch.   It's what I refer to as a BOFFFF, or a big old fat fecund female fish.   Fisheries scientists hypothesize that BOFFFFs are critically important to maintaining a large population for the future because they are experienced breeders and produce more and larger eggs per body mass than smaller females.    The BOFFFF hypothesis has never been scientifically evaluated for exploited catfish populations, so we can't know for sure.   But the 62 pound Flathead Catfish was certainly a fish of a lifetime. 

Flathead Catfish   CC BY 2.0  USFWS 

References 

Hilling, C.D., A.J. Bunch, J.A. Emmel, J.D. Schmitt, and D.J. Orth. In Press.  Growth and mortality of invasive Flathead Catfish in the tidal James River, Virginia.  Journal of Fish and Wildlife Management 10(2)

Massie, D.L., G.D. Smith, T.F. Bonvecchio, A.J. Bunch, D.O. Lucchesi, and T. Wagner. 2018. Spatial variability and macro-scale driver of growth for native and introduced Flathead Catfish populations. Transactions of the American Fisheries Society 147:554–565.