Author : Michelle Kathleen Gutsch
Publisher :
ISBN 13 :
Total Pages : 190 pages
Book Rating : 4.:/5 (827 download)
Book Synopsis Identification and Characterization of Juvenile Coho Salmon Overwintering Habitats and Early Spring Outmigration in the Anchor River Watershed, Alaska by : Michelle Kathleen Gutsch
Download or read book Identification and Characterization of Juvenile Coho Salmon Overwintering Habitats and Early Spring Outmigration in the Anchor River Watershed, Alaska written by Michelle Kathleen Gutsch and published by . This book was released on 2012 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Alaska, winter months are likely a crucial time period for juvenile salmon; however, this aspect of their ecology is poorly understood. Our goal was to examine the role of groundwater in moderating the severity of overwintering habitat conditions and the strength of selection of these habitats by juvenile coho salmon in side and peripheral channels representing a range of groundwater influence in the Anchor River, Alaska. We also investigated the effects of overwintering habitat features on the timing of juvenile coho salmon outmigration. In fall 2010 and spring 2011, we sampled 25 sites along the south fork of the Anchor River. We related catch per unit effort of juvenile coho salmon to habitat conditions within these sites; in addition, we collected individual information on fish (length) and tagged a subset of captured individuals for later recapture during outmigration. In summer 2011, outmigrating fish, including tagged individuals, were recaptured using a screw smolt trap; we related the timing of outmigration to both individual characteristics of the fish and characteristics of the overwintering site in which individuals were originally tagged. Our results indicated that the amount of groundwater, dissolved oxygen (% saturation), and invertebrate density were determinants of age-1+ coho salmon abundance in overwintering habitats. We were unable to model data from age-0 coho salmon due to assumption violations, but my data indicated that these fish distributed themselves differently than age-1+ fish, with greater abundances in areas with less groundwater influence. From the outmigration model, we determined that a high proportion of groundwater (60-96%) of the overwintering site and long fish length in the fall before winter lead to earlier spring outmigration. Variability in coho salmon lengths observed within overwintering habitats was not reflected in the relative uniformity of outmigrating individuals in length, suggesting that body size is a critical smolting cue. My study provides strong evidence for the importance of groundwater influence in providing high-quality winter habitats for age-1+ coho salmon and allowing for earlier outmigration in improved condition.