Biocontrol, electrofishing, and feminine crawdads

Wednesday, July 6, 2011 - 6:55pm



Last Friday, Katie and I accompanied Kim around Harriman State Park to release bio-control flies. The flies were designed to control the Canada thistle that is invasive in the area. They had really pretty wings with a black and white striped pattern. We got to see new areas of the park and climb through sagebrush to place the flies on the thistle. Apparently the flies are a more efficient and cost-effective method of controlling the thistle and don’t involve putting chemicals in the park. They have been thoroughly tested and don’t attack the native thistle. It seemed like an ideal solution.

After a long Fourth of July weekend, we went to Thurman Creek to go electrofishing yesterday for the first time. All of the interns were there working, but it was definitely hard work! Two people were carrying the electrofishing equipment and shocking the fish while two others had nets to catch the fish and two more had buckets to carry the fish we caught. We were all learning how to do it (except Anne Marie, of course) so we had a couple more fish fatalities than we had hoped for. It was fun to see the number of fish swimming in the creek. We saw larger ones than we had seen before there. Because we were so new at electrofishing, we saw a couple big fish that we didn’t end up catching, but I am sure with practice we will get more efficient.

While we were waiting for everyone to get to the weir earlier in the day, Katie and I counted the fish and crawdads in the trap. The number of fish was much lower than it has been for the last few weeks, but the number of crawdads was huge. We counted more than 400 of them! We decided to try informally tracking the crawdads to see if they move much in the creek, so we took a random sample and painted them with coral colored nail polish on their shells. We don’t know if the nail polish will stay on or if tracking them will change anything, but it will make counting them in the future more fun.