Trophic pathways supporting Arctic grayling in a small stream on the Arctic Coastal Plain, Alaska

Ecology of Freshwater Fish
By: , and 

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Abstract

Beaded streams are prominent across the Arctic Coastal Plain (ACP) of Alaska, yet prey flow and food web dynamics supporting fish inhabiting these streams are poorly understood. Arctic grayling (Thymallus arcticus) are a widely distributed upper-level consumer on the ACP and migrate into beaded streams to forage during the short 3-month open-water season. We investigated energy pathways and key prey resources that support grayling in a representative beaded stream, Crea Creek. We measured terrestrial invertebrates entering the stream from predominant riparian vegetation types, prey types supporting a range of fish size classes, and how riparian plants and fish size influenced foraging habits. We found that riparian plants influenced the quantity of terrestrial invertebrates entering Crea Creek; however, these differences were not reflected in fish diets. Prey type and size ingested varied with grayling size and season. Small grayling (<15 cm fork length (FL)) consumed mostly aquatic invertebrates early in the summer, and terrestrial invertebrates later in summer, while larger fish (>15 cm FL) foraged most heavily on ninespine stickleback (Pungitius pungitius) throughout the summer, indicating that grayling can be insectivorous and piscivorous, depending on size. These findings underscore the potential importance of small streams in Arctic ecosystems as key summer foraging habitats for fish. Understanding trophic pathways supporting stream fishes in these systems will help interpret whether and how petroleum development and climate change may affect energy flow and stream productivity, terrestrial–aquatic linkages and fishes in Arctic ecosystems.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Trophic pathways supporting Arctic grayling in a small stream on the Arctic Coastal Plain, Alaska
Series title Ecology of Freshwater Fish
DOI 10.1111/eff.12336
Volume 27
Issue 1
Year Published 2018
Language English
Publisher Wiley
Contributing office(s) Coop Res Unit Seattle
Description 14 p.
First page 184
Last page 197
Country United States
State Alaska
Other Geospatial Crea Creek