A method for predicting the harvest of commercial Dungeness
crab (Cancer magister) one year in advance of the fishing season is
described. The technique is based on the hypothesis that the relative
abundance of sub-legal crabs one year is directly proportional to the
harvest of legal crabs the following year....
Methods and utility of age determination of yellowtail rockfish
(Sebastes flavidus), canary rockfish (Sebastes pinniger), and black
rockfish (Sebastes melanops) collected off Oregon during 1972 to
1975 are discussed. Structures compared on the basis of the reproducibility
of counts of annuli (consistency of readings) were the anal fin
pterygiophore, opercle,...
The distribution and trophic ecology of neritic reef fishes was
studied to provide biological information useful in conserving these
stocks. Houk and line fishing was conducted from July 1976 to July
1977 on neritic reefs within 5 km of the Oregon coast adjacent to
Depoe Bay. Sampling was designed to...
The results of research designed to develop a synthesized diet
as a substitute or supplement to algae for culturing the Miyagi strain
of juvenile Pacific oysters, Crassostrea gigas (Thunberg) are
reported. The growth of juvenile Pacific oysters fed equal amounts
(based on ash free dry weights [AFDW]) of algae (Pseudoisochrysis...
The sample ratio of sublegal to legal male crabs retained in crab
pots was used in calculations to predict future harvest of Dungeness
crabs, Cancer magister, along the Oregon coast. Accurate predictions
by this method require a sample ratio representative of the population
ratio. I sampled the Oregon Dungeness crab...
Samples of weathervane scallops taken on Oregon Department of
Fish and Wildlife cruises off Oregon waters during 1981-1982 were
analyzed for a comparative growth study. No evidence of internal
growth marks were found in the shell structure when analyzed by the
acetate peel technique. Internal growth lines formed in the...
An analysis was conducted to estimate the minimum mesh
size for managing the common Chilean hake (Merluccius gayi)
fishery. Secondary objectives were to establish the
selective relationship between mesh size and fish length,
to examine growth patterns and related parameters, and to
estimate the critical age (or optimum size) at...
Data were gathered on the life history of the pile perch
(Rhacochilus vacca) from Yaquina Bay, Oregon, between April,
1966, and July, 1967. Pile perch feed on the bottom and consume
mostly molluscs, barnacles and decapod crustaceans. Food habits
varied among seasons and locations within the bay, whereas the
diet...
Data are presented on the life history of snake
pricklebacks, Lumpenus sagitta, collected in Yaquina Bay,
Oregon, from June 1977 to October 1978. Specimens were
collected primarily by beach seine from four sampling sites
in the bay. Snake pricklebacks feed on algae (mainly genus
Enteromorpha), on polychaeta (mainly genus Neoamphitrite),...
Numerous fishery researchers have attempted to preserve viable fish sperm, but only three investigations were successful in the fertilization of fresh eggs with frozen and thawed sperm: Blaxter (1953); Hoyle and Idler (1968); and Graybill and Horton (1969). Significant advances reported in this thesis were: the development of suitable life...
Successful fertilization of fresh steelhead trout, pink salmon, kokanee, chum salmon, fall chinook salmon, and coho salmon eggs with cryopreserved sperm is reported in this thesis. A mean percent fertilization greater than 50 percent was achieved for all species tested except chum salmon. Differences in sperm viability from donor males...
Reported are results of a study of otolith nuclei as a means to separate juvenile steelhead trout (Salmo gairdneri) from juvenile rainbow trout (S. gairdneri) which co-exist in the lower Deschutes River, Oregon. An intensive recreational fishery necessitated development of a technique for separation so that the impact
of the...
Fishery researchers have attempted to preserve viable fish sperm for extended periods of time. Only limited success has been achieved with storage of spermatozoa from salmonids. The principal accomplishments of this investigation during the fiscal year 1966-1967 were the development of standard methods for the collection
and evaluation of fish...
The 1988 status of yellowtail flounder stocks off the U.S. coast
of the Northwest Atlantic is assessed using U.S. and distant water
fleet commercial fishery statistics and Northeast Fisheries Center
bottom trawl survey data. Assessments of Southern New England and
Georges Bank stocks are revised using virtual population analysis of...
Signal crayfish Pacifastacus leniusculus were studied in Lake Billy
Chinook, Oregon, during 1994 and 1995. Because little was known about the
crayfish population, this study was conducted to obtain reliable estimates of life
history and population parameters, document historic commercial harvests, and
make management recommendations. Crayfish were captured with baited...
Recreational angling pressure has recently increased in the neritic
reef areas off the central Oregon coast. This study describes
weight-length and age-length relationships as well as ages at sexual
maturity of the black, blue, canary, yelloweye, and yellowtail rockfish
(Sebastes melanops, S. mystinus, S. pinniger, S. ruberrimus, and
S. flavidus,...
Growth characteristics of otoliths were used to determine age, and to separate known races and stocks of steelhead trout (Salmo
gairdneri). Otoliths were the first calcified structures observed in X-ray photographs of steelhead embryos, and a continuous record of events through life was interpreted from these structures. A direct
relationship...
In the fall and winter of 1965, 1966, and 1967, 298 ratfish (180 males, 118 females) were collected off the Pacific coast of
Oregon and Washington and examined for food habits , parasites, growth relationships and a method of age determination. The following
food organisms were found to be the...
Results of a study of spatial and temporal utilization of a tidal river estuary by hatchery and wild juvenile salmonids
(Oncorhynchus spp. and Salmo spp,), of overlap in food habits of hatchery and wild juvenile salmonids, and of size and relative
abundance of associated fish species are reported in this...