Colorado Trout Unlimited, it's chapters, and volunteers helped Colorado Parks and Wildlife clip fins of Cutbow Trout as part of CPW's ongoing study of diploid vs triploid trout in Eleven Mile Reservoir. Volunteers, along with staff from CPW helped clip over 26,000 fish in just the first day at the Mt. Shavano Fish Hatchery in Salida. Over the last two years, 97 volunteers helped clip over 148,00 fish in a six day period.
The study focuses on the size comparisons of the diploid and triploid trout. Diploid trout are the typical with only two chromosomes. In comparison, triploid trout have three chromosomes, making them sterile. The third chromosome is added during egg development through a pressure shock treatment method.
The triploid, or sterile trout, are believed to grow bigger in length and girth due to the assumption that they will use more energy for growth while the diploid trout will use up much needed energy for reproduction.
The fish used in this study are Rainbow X Cutthroat hybrid trout. Or commonly known as Cutbow trout.
Volunteers would clip the left pectoral fin on all of the diploid trout and the right fin for all triploid trout. These fish will be stocked into Eleven Mile Reservoir in February by CPW fish biologists, led by Jeff Spohn.
Due to the weak current in Eleven Mile Reservoir, these fish will be able to survive and adapt perfectly fine without a fin. According to Spohn, if the fish were placed in a river, it may hinder their ability to swim.
CTU helped with this event last year and over the course of three days, 70 volunteers clipped over 68,000 fish that were then stocked for the study.