Night electrofishing was a great experience last Monday. We headed out on to the river just as the sun was going down. The reason we boat electrofish at night is that fish become more active and move closer to the surface of the river. It was still day light out when we arrived at the power plant, so we reviewed safety precautions and proper techniques until the sun had completely sank below the horizon. We motored over to our sample location downstream of the power plant and filled our live wells with water. Next, we fired up the generators, turned on the electrofishing unit, lowered the electrodes into the water, illuminated the bow of the research vessel, and positioned ourselves to net the tetanized fish. Our sampling consisted of a reach of 1200 seconds beginning at our sample site downstream of the power plant. In our research vessel, one intern regulated the voltage of the electrofishing unit, one intern placed the netted fish in to the live wells, and four interns netted fish from the bow of the research vessel. Once we finished our designated reach, we recorded the lengths and weights of the fish and released them back in to the river. We kept the minnows for later identification and for tissue samples.
Tuesday entailed identifying the minnows we sampled the previous night and a behind the scenes tour of the Newport Aquarium. We used dichotomous fish keys to correctly identify the minnows. Next, we grouped the minnows together by species and recorded their weight. Later that day, we drove to the Newport Aquarium for our behind the scenes tour. An employee at the aquarium talked us through his daily routine and the various tasks that need to be completed for the aquarium to function properly. The most interesting exhibits we toured consisted of the shark rays, Amazon fish (including a few arapaima), and the paddlefish.
On Wednesday, we went to the Cincinnati Museum Center to further process our DNA samples and we also went night electrofishing that evening. At the Museum Center, we continued the process of extracting the DNA from our samples so that we can eventually run our samples through the DNA sequencer. This involved multiple steps using the centrifuge for twenty-minute intervals. Once completed, our samples were ready for the DNA sequencer. However, that step will not be completed until we have our other samples processed to the same phase. That evening, we went electrofishing above the power plant for a reach of 1200 seconds. While electrofishing, we were able to net four Asian carp. Dr. Lorentz stated that we have been shocking more Asian carp this year than he has in previous years on this section of the Ohio River. When we finished the reach, we completed our usual routine of recording the length and weight of each fish that we sampled.
The week concluded with our research group identifying minnows on Thursday and having the day off on Friday. With our day off on Friday, a colleague and I went on a canoe adventure on Elkhorn Creek. It was a beautiful stream with a diversity of fish. However, the particular fish that we were seeking was the smallmouth bass. We caught a few on our fishing rods and released them back into the creek. Overall, it was a good day.
Thanks for reading,