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our streamside "O.R."
Montana Fish, Wildlife and Parks
Some of you might be wondering, “How do they get radios into those fish in the Missouri-Yellowstone Adopt-A-Fish program?”
Rumors have been swimming around that we mount the radios on the backs of fish like jet packs with zip ties and duct tape. That rumor is not true.
A select few individuals are surgically trained to use a scalpel and needle to place the transmitter inside the fish. In the Adopt-A-Fish program, the spiny soft shell turtles do get the transmitters put on the outside of their shells. But fish are handled differently.
The goal of surgically implanting a transmitter is to have as little change as possible to the fish but still getting a transmitter in so we can learn things from the individual.
We learn about how far fish move or don’t move and how often. We learn the patterns of the movement such as spring spawning migrations and wintering areas. And, we learn about what habitats the fish use and when. The cool part of the adopt-a-fish program is that you get a chance to follow along and learn with us.
The process goes like this. The crew drifts nets to capture fish to be implanted. Once the fish is captured, it’s placed into a holding pen in the water, kind of like a hospital waiting room.
Before the fish is put under the scalpel, we first weigh and measure it. When we are ready to start a surgery, it’s placed on the “surgery table” which could be inside a shallow tank of water for big fish, or in a PVC pipe modified to hold a smaller fish.
The fish might be out of water for several minutes and it needs water to keep moist and to keep breathing, much like oxygen masks or tubes may be needed for people during surgery. We use a water pump to circulate water into the fish’s mouth and over its gills so the fish can still breath.
We keep as much of the fishes body wet to prevent drying them out which can be very unhealthy for fish, while at the same time we keep water out of the incision during the operation. The fish, surprisingly, stay pretty calm with just using water, but the crews have the option to use sedatives if a fish is too feisty to handle.
Once the fish is calm and the cutting area is cleaned, a sterilized scalpel is used to make a small incision in the abdomen about four inches in length. From there, the radio, which is about the size of AA battery, is placed into the body cavity and the antenna exits a few inches behind the incision.
Fish have to be big enough to have a transmitter in it and the transmitter must be only a small addition to the fish’s total weight. The fish needs to be able to swim normally after the surgery and not be dragging its belly on the bottom because the radio is too big.
With the radio placed gently into the fish, the incision is either stitched or stapled closed by using sutures or medical staples. The fish is then placed into a recovery room (the holding cage in the river) before being released back into the river to ensure the surgery went well. After we are sure the fish is recovering and ready to go it’s off to the murky waters to continue it’s daily routine.
It takes a few weeks for the fish to completely heal from the surgery.
Our surgical staff’s job is complete and the fish live on to show where they live at different times of the year. The results have been amazing. We’ve learned that many of them move much farther than we ever expected.
Our big mover of the week on the lower Missouri River was potentially Paddlefish #1 moving about 7 miles up the Missouri, possibly heading for the Milk River.
It looks like paddlefish #3 and a slug of other fish did in fact go up the Milk. We checked our telemetry ground station and it showed a bunch of fish moving upstream, which tells us just how important the Milk River is to the fish of the lower Missouri.
Ryan Lott is a fisheries biologist with Montana Fish, Wildlife and Parks stationed at Fort Peck.