Mobile Asian carp Surgical Hospital
BY ERIC BROSSMAN AND CORY ANDERSON, CARTERVILLE FWCO-WILMINGTON SUBSTATION
Within the last two years, the Carterville Fish and Wildlife Conservation Office (FWCO) Wilmington Substation has expanded the monitoring of juvenile Silver and Bighead Carp distribution to include a telemetry study in the Peoria reach of the Illinois River. The purpose of this study is to track the movements of juvenile Silver Carp and correlate fish movements with factors such as population density, hydrology, habitat, and water quality. This data will provide valuable information about how far these fish move and what habitats they prefer during different times of the year, information that can greatly improve monitoring efforts.
Movement of tagged Silver Carp are recorded by radio receiving stations and hydroacoustic receivers installed along the river channel, side channels, and backwaters of the Peoria reach. When a tagged fish swims within the proximity of one of these receivers, its ID tag is logged along with the date and time. Before any of these data can be collected, however, the telemetry tags must be implanted in fish.
Surgically implanting telemetry tags is quite an operation (pun intended). An entire surgery team is organized to facilitate a smooth and speedy process from the second the fish arrives at the tent to their eventual release in the river. This is because they are already under a great deal of stress from simply being captured. Like any surgery, a myriad of activities can be seen taking place and everyone has a job to do.
Asian carp are brought in from the capture team and are first held in a holding tank, which has salt added to the water to help facilitate oxygen diffusion across their gills and regeneration of their slime coat. When the surgeon is ready, the fish’s length, weight, and sex is recorded. Then the data recorder preps and assigns each fish a specific telemetry transmitter and floy tag; the size of the fish will dictate the size and type of the transmitter used. Next, the fish is placed upside down onto a special surgery board and a breathing tube flowing oxygenated river water is inserted in the fish’s mouth. Once the fish is sedated, the surgeon makes an incision is in the body cavity near the anal fin and implants the tag. The wound is closed with sutures, sterilized once more, and then the fish is placed into a recovery tank to be monitored by a release team.
This tagging process results in a remarkably quick recovery. Fish are released once they are able to swim away from the releaser’s grasp and maintain proper buoyancy in the tank. The surgical process is an organized whirlwind of activity to ensure the fish are returned quickly and are healthy. It seems unusual ensuring that an invasive species returns to the water healthy but the results of the telemetry study will provide extremely valuable information in the fight against the spread of Asian carp.