- Why Colby?
- Request Information
- College Profile
- Scholars Programs
- Student Perspectives
- Alumni Success
- For Counselors
- Contact Admissions
ES Student Profile
Sasha Bartels '08
Rubenstein School of Environment and Natural Resources Research Assistant
My name is Sasha Bartels and this summer I took part in several graduate studies at the Rubenstein School of Environment and Natural Resources working with Donna Parrish and Ellen Marsden at the University of Vermont. The Rubenstein School promotes research and graduate student training in the ecology and management of fish, wildlife and their habitats. The major project I worked on involved controlling sea lamprey in Lake Champlain. Sea lamprey significantly reduce lake trout survival and fishing opportunities for trout and salmon. I was investigating lamprey migratory and sex pheromones in order to determine which tributaries contribute the most to the lamprey population. Sea lamprey control in the Great Lakes and Lake Champlain is currently dependant on use of chemical lampricides to kill larval lamprey, and barriers to prevent spawning. The lamprey spawn emit a pheromone that attracts the adults to the right tributary. When the adult lamprey pick up the pheromone, they know that the tributary is a viable breeding ground. The male lamprey enter the tributary before the females, and once the males reach the breeding ground, they emit a sex pheromone that attracts the females. This study looked at if the amount of pheromone in traps would cause the females to prefer one trap to another even with background pheromone. This study is unique because it looks at the effect of pheromone in the field as opposed to in the laboratory.
For this study I spent time monitoring the large tanks of lamprey that were separated by sex. I took and recorded the temperatures of the tanks every day to make sure it was at the correct temperature to maximize the lifespan of the lamprey and to make sure that the temperatures of the two tanks were the same. I also counted the number of lamprey in each tank everyday and removed the dead lamprey. I collected the lamprey that were caught in traps in the stream and tagged them. I also went out in the field and collected and tagged more lamprey directly from the streams by walking upstream and looking for lamprey nests. After tagging the lamprey we had to determine if the females were releasing eggs and if the males were releasing motile sperm. This had to be the case for our experiment because the females wouldn’t respond to the pheromone released by the males unless they were releasing eggs. The males would not necessarily be releasing hormone unless their sperm were motile. In order to determine this we had to collect sperm from the males and look at it under a microscope. The males with motile sperm and the females that were producing eggs were kept in a separate acclimation tank. Unfortunately, do to the weather and death of lamprey, we were not able to complete our experiment. We did determine that when ten male lamprey were put in one trap and one male lamprey was in the other, we caught more lamprey in the trap with ten males.
I also took part in a study on the declining lake trout population in Lake Champlain. The study looked at the predation on the lake trout. I spent over a month cutting open over 300 fish, recording their lengths, weights, stomach contents, and the weight of the stomach contents. I also went out and trawled on Arnold’s Bay trying to find lake trout, and recording the species and number of fish we caught. While cutting open fish, if we found any lake trout fry, we would record their length and what fish they were found in, and then we would preserve them in alcohol. Most of the trout were being eaten by yellow perch and rock bass. During all of the times I trawled, we never found an adult lake trout.
I also took part in a research project looking at the way science articles in the field of fish sciences have changed over the years. I looked up articles in Web of Science for “watershed AND fish” from 2002-2004. Then I tried to find the full text versions of the articles using Colby Libraries and UVM libraries.