T. Bentley, Kale Schindler, Daniel E. B. Armstrong, Jonathan J. Cline, Timothy T. Brooks, Gabriel Inter-Tributary Movements by Resident Salmonids across a Boreal Riverscape <div><p>Stream-dwelling fishes inhabit river networks where resources are distributed heterogeneously across space and time. Current theory emphasizes that fishes often perform large-scale movements among habitat patches for reproduction and seeking refugia, but assumes that fish are relatively sedentary during growth phases of their life cycle. Using stationary passive integrated transponder (PIT)-tag antennas and snorkel surveys, we assessed the individual and population level movement patterns of two species of fish across a network of tributaries within the Wood River basin in southwestern Alaska where summer foraging opportunities vary substantially among streams, seasons, and years. Across two years, Arctic grayling (<i>Thymallus arcticus</i>) and rainbow trout (<i>Oncorhynchus mykiss</i>) exhibited kilometer-scale movements among streams during the summer growing season. Although we monitored movements at a small fraction of all tributaries used by grayling and rainbow trout, approximately 50% of individuals moved among two or more streams separated by at least 7 km within a single summer. Movements were concentrated in June and July, and subsided by early August. The decline in movements coincided with spawning by anadromous sockeye salmon, which offer a high-quality resource pulse of food to resident species. Inter-stream movements may represent prospecting behavior as individuals seek out the most profitable foraging opportunities that are patchily distributed across space and time. Our results highlight that large-scale movements may not only be necessary for individuals to fulfill their life-cycle, but also to exploit heterogeneously spaced trophic resources. Therefore, habitat fragmentation and homogenization may have strong, but currently undescribed, ecological effects on the access to critical food resources in stream-dwelling fish populations.</p></div> pit;summer foraging opportunities;resource;Wood River basin;anadromous sockeye salmon;population level movement patterns;individual;Rainbow Trout 2015-09-17
    https://plos.figshare.com/articles/dataset/_Inter_Tributary_Movements_by_Resident_Salmonids_across_a_Boreal_Riverscape_/1547138
10.1371/journal.pone.0136985