The use of some age determination methods may result in the
incorrect age structure of fish populations. This in turn may lead
to incorporation of inappropriate data into models used for stock
management. Otoliths are commonly used for determining the age of
fishes, and ages based on the whole otoliths...
Data from the coho salmon migration were examined from three streams of the Alsea Watershed Study, conducted on tributaries to Drift Creek, Oregon, from 1959 through 1973. With the migration season defined as November 1 through May 31, the mean seasonal smolt count was 2022 fish in Deer Creek, 665...
Regions of similar species composition and groups of demersal fish
species with similar distribution patterns from Cape Flattery,
Washington to Point Hueneme from 50-250 fm (93-460 rn) were defined based
on results of an agglomerative cluster analysis of National Marine
Fisheries Service Rockfish Survey data taken during the summer of...
The migrations, distribution, and feeding of American shad, Alosa
sapidissima (Wilson), were studied from February 1980 through January
1981 in the Columbia River Estuary, an important rearing zone for
young-of-the-year shad. Sampling was performed with purse seine,
beach seine, and otter trawl.
Adult shad and large numbers of juveniles from...
One hypothesis proposed to explain how the endocrine
system controls reproductive cycles in seasonally breeding
animals is that the hypothalamus undergoes seasonal
changes in sensitivity to negative feedback by gonadal
steroids. The result is seasonal changes in the secretion
of luteinizing hormone-releasing hormone (LHRH) and
gonadotropin secretion. The present experiments...
Nest sites of reticulate sculpin (Cottus perplexus) were located in two stream reaches, one from a basalt basin and one from a sandstone basin. Stream reaches were similar in gradient, basin area, elevation, climate, and riparian vegetation but differed in biologic community structure and substrate characteristics. An electivity index was...
