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An experimental method that marks hatchery-raised fish by staining their skeletons instead of clipping their fins is enabling researchers to better track fishes’ fates across more lakes, at a lower cost, and with less stress to the fish.
The marking method is an important piece of an ongoing Department of Natural Resources study on 24 northern lakes to evaluate the effectiveness of stocking those lakes with walleye, according to Jeff Kampa, a fisheries research technician working on the study.
It allows researchers to track the fates of fish that otherwise would be too small to mark using traditional methods like fin clips. It also allows researchers to mark thousands of fish at a time.
The marking method, which the Department of Natural Resources and other states are seeking federal approval to use on a widespread basis, involves immersing hatchery-raised fry in water treated with oxytetracycline, an antibiotic. This treatment stains the bones of the fry in a way that can be detected only by examining the bone under ultraviolet light, where the mark appears as a gold band, Kampa says.
The oxytetracycline does not appear in the fishes’ flesh, nor does it pose a health concern for people who eat fish that may be marked with the antibiotic. The DNR and other partner states are using the antibiotic under a permit from the U.S. Food and Drug Administration
Based on the success a DNR fish manager had in using the marking technique in another study on Lake Kegonsa in Dane County, and initial signs that the marking method is working well on the 24-lake study, the DNR may expand its use of this marking method, Kampa says.
"If it is this simple to mark large numbers of fry in so short a period of time, it may become part of a routine for all fish stocking where we need to track survival statistics," he says.
FOR MORE INFORMATION: Jeff Kampa (715) 635-4166; Martin Jennings (715) 635-4160 or Mike Vogelsang (608) 273-5946.
Uploaded: 10/9/1999
Uploaded: 10/9/1999