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
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26995 |
| Date | 28 February 1990 |
| Creators | Wilson, Matthew T. |
| Contributors | Pearcy, William G. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Relation | North Coast Explorer |
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