Dissertation/Thesis Abstract

Use of hydroacoustics to examine spatial and temporal patterns of Pacific salmon (Oncorhynchus spp.) behavior during spawning migrations in Nushagak River, Alaska
by Simpson, Samantha C., M.S.E.S., Alaska Pacific University, 2014, 151; 1555183
Abstract (Summary)

The Nushagak River, Bristol Bay, Alaska, supports one of the largest wild sockeye salmon (Oncorhynchus nerka) runs in the state and also supports overlapping runs of chum (O. keta) and Chinook (O. tshawytscha) salmon. Each summer, the Alaska Department of Fish and Game deploys dual-frequency identification sonar (DIDSON) on the river to enumerate salmon to monitor escapement goals; however, salmon behavior and spawning run characteristics at the site are not incorporated into management. We investigated the feasibility of using Nushagak River DIDSON data from 2008-2011 to identify trends in run timing and compare passage rates to local environmental conditions, including tide, light intensity, and water temperature. We also used spatial analysis to examine aggregation behavior of salmon at the DIDSON site at multiple distance scales. Between all four years, run timing only varied within a few days (< 1 week), regardless of water temperature. In 2009 and 2011, more salmon passed upriver during slack and ebb tides than during flood tide. Salmon were never completely spatially random, and distance scales of aggregation behavior were influenced by run period and photo period. When examining all factors together, the interaction between salmon density and run period affected distance at maximum aggregation. This research used hydroacoustics for a multi-level approach to investigating spatiotemporal patterns of Pacific salmon relative to environmental factors during their spawning migration and may help refine in-season monitoring and management of the fishery.

Indexing (document details)
Advisor: Harris, Bradley
Commitee: Buck, Gregory, Dial, Roman
School: Alaska Pacific University
Department: Environmental Science
School Location: United States -- Alaska
Source: MAI 52/06M(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Ecology, Zoology, Aquatic sciences
Keywords: Aggregation, Bristol Bay, Alaska, Environmental factors, Oncorhynchus keta, Oncorhynchus nerka, Oncorhynchus tshawytscha, Pacific salmon, Upriver migration
Publication Number: 1555183
ISBN: 9781303870095
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