A few weeks ago, we went to a fee fishing facility located on a 40 acre lake. The spring-fed lake had been stocked with several species, including yellow perch, bluegill, smallmouth bass, and a few rainbow trout. For the VHS surveillance testing work we are doing this summer, we are taking samples from 60 fish per farm. Most farmers use nets or traps to collect the 60 fish necessary for testing. When we arrived to this facility, however, the farmer had no equipment but one fishing pole! I volunteered for the job of “fisherman.” What a fun day! I got to catch 60 fish…and get paid to do it! Although there were many fish species in the lake, all 60 I caught were yellow perch. We suggested putting in predators such as pike to clear out some of the perch, as the farmer was disappointed that the perch population so outnumbered the other fish. I’ve included a picture of me having fun fishing!
The only way to test for VHS is by taking tissue samples. We are as humane as possible when euthanizing the fish to collect these samples. If the farmer does not wish to keep the fish for food, we euthanize them with a chemical known as MS-222. It is commonly used on fish farms as an tranquilizer or anesthetic for egg or milt (sperm) collection, fin clipping or tagging, immunizing, etc and in the pet fish business for surgeries, physical exams, and more. If used at the correct dose, it induces a quick and humane death. The second picture is of me with a fish I just euthanized with MS-222. Fish euthanized with MS-222 need to be buried to prevent injury or death to wildlife or birds that may prey upon the carcasses. If the farmer wishes to fillet the fish for food, MS-222 is not used because it would be unsafe to eat the meat. In this case, we pith the fish, which is also considered humane euthanasia for fish by AVMA.