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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Residence and growth of juvenile chum salmon (Oncorhynchus keta) in Netarts Bay, Oregon

Wilson, Matthew T. 28 February 1990 (has links)
Estuarine residence and growth of juvenile chum salmon (Oncorhynchus keta) from Netarts Bay, Oregon were estimated from daily-formed growth increments of sagittal otoliths which are distinguishable from accretion patterns formed during freshwater residence. Estuarine residence time was inversely related to the average size at which juvenile chum salmon entered Netarts Bay. Among fin-clipped, hatchery fish, large individuals disappeared from Netarts Bay more rapidly than smaller members of the same release group during the first 9 days of estuarine residence. This selective removal was not evident among creek-reared chum which were smaller than the fin-clipped fish. Size-related emigration explains this variation in residence time. Growth rates were estimated from back-calculations of fork length from otoliths. The growth rates of juvenile chum salmon in Netarts Bay (0.6 mm FL/d; 3.5% bw/d) were lower than growth rates in other estuaries where harpacticoid copepods were a major prey item. Juvenile chum salmon that entered the estuary early in the spring grew faster than those which entered later in the year, possibly because of lower water temperature and lower density of small (50 mm FL) chum during the early period. High water temperature reduced apparent growth rates by slowing growth and causing emigration of larger, faster-growing individuals. / Graduation date: 1990

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