Keeping tabs on fish population

Larry White
10-19-2005

Biologists recommend taking a certain number of bass and bream out of a pond each year to keep things in balance. They also recommend releasing many of the larger fish back into the pond to maintain a healthy balance and provide more big fish to catch later. The problem is keeping up with the true growth rate of the fish since there will always be some large fish and some small fish in the pond. One of the easiest and most fun ways to monitor the fish growth in a pond is to tag them. A fish tag is simply a three-inch piece of colored plastic about the size of pencil lead with identifying numbers on it. This remains outside of the fish. There is a smaller piece of plastic that fits into the needle on the tagging gun. When the needle is inserted behind the dorsal fin on the fish and the trigger is pulled, a plunger pushes the smaller piece of plastic under the skin of the fish and the needle is removed, leaving the tag attached to the fish. No damage is done to the fish with this process. When tagging the fish, record the tag number, date, location in the pond where the fish was caught, measurements and weight of the fish. Keep this information in a notebook. Later, each time a tagged fish is caught; compare the present information to what was recorded in your notebook when the fish was tagged. You might be surprised at what you learn about the fish in your pond. For instance, you might discover that one certain fish is caught and released five or six times in a single month, or you may never catch some of the fish again. Some fish may gain a lot of weight in a single year while others may gain only a little. Some fish may be caught very close to the place where they were first tagged and others may have moved to the opposite end of the lake. After you have tagged about 20 or 25 fish in the lake, you can now figure the ratio of tagged and untagged fish that you catch each trip. This will give you an idea of the population of fish in the lake (it is not necessary to try to tag every fish in the pond). Although some people tag and release fish in our local lakes and rivers, the odds of the same fisherman catching one that he tagged are really rather slim because of the sheer size of the impoundment. It works much better in a smaller lake or pond of about 50 acres or less. Fish tagging can be loads of fun and add a whole new dimension to your fishing experience. It may also give you some valuable information that could improve your fishing in other lakes.

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