Lake Trout (Salvelinus namaycush) and Arctic Grayling (Thymallus arcticus) Diet, Population, and Migration Dynamics in Arctic Ecosystems

• Main Author: Miano, Andrew
• Format: Text
• Language: unknown
• Published: Digital Commons @ Connecticut College 2013
• Subjects: Aquaculture and Fisheries; Marine Biology; Arctic; Arctic grayling; Climate change; Thymallus arcticus
• Online Access: https://digitalcommons.conncoll.edu/biohp/13; https://digitalcommons.conncoll.edu/cgi/viewcontent.cgi?article=1012&context=biohp

Climate change has already increased temperatures in Arctic ecosystems and is predicted to continue warming these ecosystems at double the pace of the rest of the world. Increasing temperature coupled with other effects of climate change are expected to have negative effects on Arctic aquatic ecosystems including higher water temperatures and increased frequency and severity of drying events in streams. My project examined lake trout and arctic grayling diets in order to assess how climate change could influence their populations. We sampled diets in Green Cabin Lake and its outflow stream, the Kuparuk River, using gastric lavage techniques and then determined dry weights of all organisms to the lowest taxonomic level feasible. During the summer in Green Cabin Lake, lake trout ate differently depending on their size while all sizes of adult grayling ate similar items. In addition, both adult grayling and smaller lake trout preyed on similar items during the summer in Green Cabin Lake, indicating possible interspecific competition. During the fall lake trout preyed more on grayling than in the summer and those grayling that migrated into the Kuparuk River for the summer had different diets from those that remained in Green Cabin Lake. The interconnectivity between lake trout and arctic grayling in this aquatic ecosystem means that climate change could severely disrupt food web dynamics in Green Cabin Lake.