by Richard Simms
As a professional fishing guide, one of the most common questions I hear when someone catches a big fish is, “How old do you think that fish is?”
Since I am a professional who always has an answer, my answer is always, “It depends.”
Growth rates among various fish species has been widely researched by biologists. The results are always widely varying, depending on exactly where the study was conducted. Such studies are not easy and in most cases require that the fish be killed. The most accurate (and only) way to age most fish is by removing the otolith. That is a small, free-floating bone in the fish’s head. It is the free-floating organ that tells the fish when it is upright, or when it is upside down. The otolith adds a growth ring during every growing season. Biologists must remove it (which requires killing the fish), slice it in half and count the rings, just like aging a tree.