Researchers can utilize fish marking as a way to determine fish growth, movement, survival, reproduction and more. This information, in turn, can be used to assess stocking success.
Therefore, CPW initiated a research project to investigate fish marking techniques. These techniques will be used to assess walleye fry (recently hatched fish) versus fingerling (juvenile fish) success after stocking[L1] .
Researchers tested oxytetracycline as a possible marking method. A type of antibiotic, oxytetracycline turns fluorescent green-yellow under a particular wavelength of light. To mark fish, researchers submerge them into an oxytetracycline solution; the fish then incorporate the oxytetracycline into their hard parts (e.g., bones). This can later be viewed in the lab after the fish is captured again in the wild after stocking.
Based on the results of this project, researchers determined oxytetracycline as an effective marking technique. This technique will be applied by biologists to monitor walleye fry and fingerling stocking success and survival.