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Selected life history aspects of American shad (Alosa sapidissima) and predation on young-of-the-year shad in Lake Umatilla of the Columbia River

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Title Selected life history aspects of American shad (Alosa sapidissima) and predation on young-of-the-year shad in Lake Umatilla of the Columbia River
Names Stainbrook, Cris Eric (creator)
Tubb, Richard A. (advisor)
Date Issued 1982-12-15 (iso8601)
Note Graduation date: 1983
Abstract Selected life history aspects of American shad, Alosa
sapidissima, collected in Lake Umatilla of the Columbia River
during 1980 and 1981 were examined and compared to other shad
populations. Mean fork lengths of adult shad captured in
1981 were 405-, 415- and 423-mm for age III, IV and V males;
425-, 444- and 457-mm for age III, IV and V females. The mean
age at maturity was determined to be 3.2 years for males and
3.5 years for females while the rate of repeat spawning was
36% and 45% for males and females, respectively. Four-year-old
shad accounted for 58.5% of the spawning adults in the two years.
Absolute fecundity ranged from 97,168 to 284,240 eggs with a
mean of 193,074 eggs per female. Young-of-the-year shad were
more abundant in 1980 than in 1981. In both years, the tail-race
zone was the most important spawning area and the island
zone the most important rearing area for young-of-the-year
shad in the reservoir. Growth of young shad in Lake Umatilla
was similar in all sampled macrohabitats and appears to be
dependent on year class strength, water temperature and water flow. Out-migrating young-of-the-yetar shad passing through
John Day Dam were significantly largjer than young-of-the-year
shad in reservoir habitats indicating size, as well as temperature, influences the timing of downstream migration. Predation
on young shad by resident predator fish species was variable
and appeared to be dependent on the Abundance of young-of-the-year
shad.
Genre Thesis/Dissertation
Topic American shad
Identifier http://hdl.handle.net/1957/41994

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