This study was undertaken to determine the identity of Philonema oncorhynchi from anadromous sockeye and Philonema agubernaculum from non-anadromous trout, and also to test the hypothesis that the worm in salmon is dependent on hormonal stimulus from the host for synchronization of reproduction. On the basis of differences found in life cycles, cross infection and starch gel electrophoresis, P. oncorhynchi and P. agubernaculum are considered to be different species. The hypothesis was tested experimentally, using salmon pituitary extracts and synthetic stilbestrol. Pituitary extracts accelerated the production of larvae in the uterus, of the worm and stilbestrol inhibited the gonadal development of the fish, but had no apparent effect on the worms. The hypothesis was further supported by the results of transplantation of adult but non-larvigerous worms from maturing sockeye into immature trout. Larval development failed to take place in recipient hosts. As well, larvigerous worms were collected only from sexually mature fish, whether 3, 4 or 5 years old. Rapid development of the worm paralleled the rapid gonadal development of the fish during the last 6 months of the fish's life. Sexually immature sockeye had only immature worms. / Science, Faculty of / Zoology, Department of / Graduate

The activity of the pituitary-interrenal axis in juvenile coho salmon (Oncorhynchus kisutch) and the relationship of this activity to the numbers of circulating leucocytes has been studied, using histological and histometric techniques. To this end, the effects of injections of mammalian ACTH, of Cortisol acetate and of dexamethasone on the interrenal tissue, on the epsilon cells in the pituitary gland, and on the differential leucocyte counts were investigated. In addition, the activity of the pituitary-interrenal axis and the related changes in leucocyte counts were determined throughout their year of stream residence. Further, the response of this axis, along with corresponding hematological changes to environmental alterations in the laboratory, were studied. Injections of ACTH resulted in a dosage-related stimulation of the interrenal tissue of coho salmon fry. On the other hand, injections of Cortisol acetate and of dexamethasone produced a marked atrophy of the interrenal tissue. All dosages of either ACTH or Cortisol acetate decreased the mean nuclear diameters of epsilon cells, and resulted in their degranulation. In addition, a decrease in numbers of circulating small lymphocytes and thrombocytes resulted from administration of all dosages of ACTH, Cortisol acetate or dexamethasone. It is proposed that the interrenal tissue of coho fry is capable of marked variations in activity, that this tissue is under pituitary control, and that a negative-feedback mechanism operates between the interrenal and the pituitary gland. Additionally, changes in pituitary-adrenocortical activity are reflected in characteristic alterations in numbers of certain circulating leucocytes. The pituitary-interrenal axis of juvenile coho salmon in their natural habitat is inactive, from the time of emergence in spring, and through summer and early fall, compared with the winter and spring samples of yearling coho. In addition, numbers of circulating small lymphocytes were decreased in the winter and spring samples of yearling coho compared with summer and autumn samples. It is suggested that the increased activity of the pituitary-interrenal axis along with changes in leucocyte counts observed in the winter sample of juvenile coho salmon are related to cold-temperature acclimation. Furthermore, it is proposed that the increased pituitary-adrenocortical activity noted in the latest of the three spring samples of yearling coho salmon is associated with the transformation from parr to smolt. The interrenal tissue of juvenile coho salmon maintained in continuous darkness, or exposed to a continuously flashing light for varying numbers of days, was generally more active than that of corresponding control fish subjected to a twelve hour photoperiod. Additionally, small-lymphocyte and thrombocyte counts for darkness-maintained and flash-exposed fish were lower than values for corresponding control samples. On the other hand, no consistent differences in activity of the interrenal tissue were found when fish maintained in continuous light for varying numbers of days and corresponding control fish were compared. It was observed that the pituitary-interrenal axis of juvenile coho salmon was initially stimulated following transfer of the fish from holding tanks to an altered environment. In addition, the activity of the interrenal tissue was increased by exposure of these fish to cold water temperatures; this increased interrenal activity was accompanied by a lymphopenia. It is suggested that the pituitary-interrenal axis of juvenile coho salmon is involved in cold-temperature acclimation. It is concluded that the pituitary-interrenal axis of juvenile coho salmon undergoes marked fluctuations in activity as a result of environmental alterations within the laboratory. Furthermore, an increase in pituitary-adrenocortical activity during acclimatization is characteristically reflected in a decrease in number of.circulating small lymphocytes. / Science, Faculty of / Zoology, Department of / Graduate

Two experiments were conducted to study the effect of protein source and level in the diet of juvenile chinook salmon (Oncorhynchus tshawytscha) reared in fresh water tanks. The protein sources compared were a freeze-dried pollock muscle and euphausid mix (9:1)(FPE), three whole herring meals processed differently from the same lot of raw herring and a casein-gelatin mix supplemented with arginine and DL-methionine (CS). The protein sources were tested at three levels of dietary protein in isocaloric diets fed to satiation to duplicate groups of fish for a 42-day period. Protein was replaced by dextrin and glucose on an estimated metabolizable energy basis. The various methods employed to evaluate protein quality yielded different values relative to FPE. In terms of growth rate and assays based on body protein gain, FPE was found to be the best protein source. Low temperature (75°C) drying of herring meal caused a slight reduction in protein quality compared to freeze-drying . High temperature (150°C) dried herring meal was found to be an extremely poor quality protein source. Although high estimates of protein quality were obtained for CS, lower food intake depressed growth in fish fed CS diets. The determination of the endogenous loss of nitrogen from fish enabled the partitioning of protein intake into the amounts used for growth, maintenance and exogenous excretion for each protein source. In Experiment 2, two series of isocaloric diets were tested containing 17 to 47% protein, in increments of 10%, provided by FPE at two levels of dietary energy. The equation y = -0.50699 + 0.25398x - 8.37872x² ,(where y = specific growth rate, and x = protein energy:total energy (PE:TE)) was derived to quantify the dietary protein requirement for juvenile chinook salmon over a 105-day period. Maximum growth was achieved at a PE:TE ratio of 0.55. However, for practical purposes the PE:TE ratio required was found to lie in the range between 0.35 and 0.55. The range permits the fish culturist to consider economic efficiency in diet formulation. / Land and Food Systems, Faculty of / Graduate

Some properties of the adenyl cyclase activity in the maturing testis of Oncorhynchus tshawytscha (chinook salmon) were characterized. The enzymic reaction was linear at 30° and at 15° for at least 60 min. The divalent cation requirement of the salmon testis enzyme was reexamined (33). The optimal concentration of Mg was about 10 mM and of Mn2+ was 5 mM; Mn2+ concentrations above 15 mM caused a marked decrease in enzyme activity. A higher maximal activity was achieved in the presence of Mn2+ than in the presence of Mg2+. Stimulation of the enzyme with the optimal concentration of F-, 12 mM, resulted in a 7-fold increase in the reaction rate over the basal activity. In efforts to solubilize the enzyme, it was found that Lubrol PX and Triton X-100 destroyed enzymic activity but Nonidet P40 and Tween 80 did not. The adenyl cyclase activity in salmon testis homog-enates was stable for at least 6 hours at 0° to 4° but was very unstable at 24°; storage of the homogenate for 24 hours at either 0° to 4° or 24° resulted in a total loss of activity. Differential centrifugation of salmon testis homog-enates which were prepared in isotonic medium revealed tnat all subcellular fractions contained some adenyl cyclase activity. About 55% of the activity sedimented at 600g while only 10% of the activity was recovered in the 105,000g supernatant. The 6300g sediment had a very high specific activity compared with the specific activity of the other fractions. The ATP analogue, adenylyl imidodipho3phate (AMP-PNP), tritium labeled in adenosine, was synthesized from tri-butylammonium imidodiphosphate and adenosine-5’ phosphor-imidazolate. Salmon testis adenyl cyclase catalyzed the conversion of AMP-PNP to cyclic AMP. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate

Anadromous pink salmon undergo several migratory movements between different habitats during their life history. These migrations are accurately timed on a seasonal basis. Annual rhythms or seasonally-timed events may result from interactions between daily rhythms and annual changes in environmental factors. Therefore, knowledge of daily behavioral rhythms in pink salmon may improve our current poor understanding of the seasonal timing of its migrations. Hence, the objective of this study was to investigate, in a seasonal context and mainly under laboratory conditions, diel rhythms of ecologically-relevant behavior in juvenile pink salmon, and their timing mechanisms. Fry emergence from a simulated gravel redd in fresh water was mainly nocturnal below 13°C. Diel emergence timing was synchronized with the onset of night, but was affected by temperature in a non-linear manner. Temperature affected negatively the duration of the intra-gravel alevin stage and the rate of emergence. Nocturnal emergence was considered an anti-predator adaptation. Fry exhibited mainly nocturnal rhythms of swimming activity and of vertical distribution during the first week after emergence. However, a gradual shift from a nocturnal to a diurnal swimming activity rhythm occurred 7 to 13 days after emergence, when wild fish are residing in estuaries and adjacent coastal waters. Coincident with this shift was an increasing tendency of the fry to swimnnear the water surface during the day. This suggested a weakening of their negative phototactic response during this period. Thereafter, the fish usually displayed diurnal rhythms of swimming activity and nocturnal rhythms of vertical distribution. The ontogenetic shift in the phase of the activity rhythm and in photobehavior was considered adaptive for schooling and feeding during the day. Wild fry fed mainly during daylight hours in littoral areas of two marine bays. However, their feeding rhythms varied among study sites. Laboratory experiments showed that hunger level affected fish feeding rate and ration consumed positively. Fish fed continuously on live copepods under idealized laboratory conditions. During a 12-h session they rapidly (< 30 min) filled their stomachs with prey; thereafter, they maintained their stomachs full by feeding at a rate that balanced the rate of evacuation of prey from the stomach. Hence, I concluded that pink salmon have flexible feeding activity rhythms, which may permit opportunistic exploitation of prey, and feed at a relatively low hunger threshold. This feeding strategy may explain in part their relatively high growth rates in nature. During the periods corresponding to their juvenile coastal and pelagic ocean phases, the fish exhibited generally diurnal rhythms of swimming activity and of aggression, and nocturnal rhythms of vertical distribution in response to simulated seasonal photoperiodic and temperature changes. These rhythms were synchronized with the artificial light-dark (LD) cycle throughout most of the year. Some parameters of these rhythms varied on a seasonal basis, but not according to the Aschoff-Wever model. Mean swimming speed, the degree of diurnalism of the swimming activity rhythm, and the timing of the daily peak of the rhythms were affected by daylength. Hence, photoperiod might be an important proximate factor that pink salmon use to time their oceanic migration on a seasonal basis. Some data suggested the existence of an endogenous, circadian activity rhythm, and thus a daily "clock", in pink salmon. However, this remains uncertain. The free-running period of their activity rhythm was not related negatively to constant light intensity, as predicted by the Circadian Rule. The LD cycle affected directly swimming activity (masking), rather than entraining an endogenous circadian system. Since the activity rhythm of pink salmon does not possess a strong endogenous component, it is doubtful that the seasonal timing of its migrations results from interactions between a circadian clock and seasonal changes in environmental factors. However, the flexibility and inter-individual variability of their behavioral rhythms may be adaptive responses to the instability and heterogeneity of the marine environment. / Science, Faculty of / Zoology, Department of / Graduate

The exploitation of salmon resources was once central to the economic life of the Northwest Coast. The organization of technological skills and information brought to the problems of salmon utilization by Northwest Coast fishermen was directed to obtaining sufficient calories to meet the requirements of staple storage foods and fresh consumption. This study reconstructs selective elements of the traditional salmon fishery drawing on data from the ethnographic record, journals, and published observations of the period prior to intensive white settlement. To serve the objective of an ecological perspective, technical references to the habitat and distribution of Pacific salmon (Oncorhynchus sp.) are included. The aim of the work is to assess the relationship of salmon technology complexes to ecological conditions at fishery sites. It is an examination of the operating principles in traditional systems of salmon production. A model of the fishery is suggested: during migration anadromous salmon pass through a number of time and space segments where they can be intercepted by fishermen. A coincidence of appropriate elements will define a fishery site, i.e., the characteristics of the prey, accessibility to resource locations, natural features of the environment, and the enterprise of fishermen. The interaction of these and their constituent variables provides a range of selective strategies to be used, analyzed in this study with reference to specific Northwest Coast ethnic divisions and geographic locations. Twenty-four ethnic or areal divisions within the Northwest Coast culture area were studied. The results of the research are presented in Part One supported by distribution maps and illustrative materials. Lists of reference tables for each of twelve systems of salmon production are contained in an Appendix. Part Two includes technical information about Oncorhynchus sp. and its habitat. Part Three is an analysis of social, ecological, and technological elements in several stages of inter-relation, including an interregional comparison in the final section. An Index of Salmon Abundance and a comparison of selected resource areas provide statistical evidence (Appendix II and III). / Arts, Faculty of / Anthropology, Department of / Graduate

No description available.

Policy decisions in fishery management are becoming increasingly complex and difficult. This is especially true for the salmon fisheries where policy outcomes affect the productivity of the salmon resource and the subsequent well-being of commercial fishermen, charter boat operators, Indian fishermen, and sport anglers. The objective of this study was to advance methodology from statistical decision analysis which would assist fishery managers in Oregon who must make particularly difficult choices with respect to allocation and production of coho salmon while recognizing uncertainties in the environment, incomplete state of knowledge, and the conflicting needs and desires of different interest groups. The method chosen given multiple objectives and uncertainty is multiattribute utility analysis. The approach consists, of two main components: (1) a computer model which simulates the life cycle of hatchery and stream spawning coho salmon given environmental variation, different hatchery juvenile release levels and harvest rates; and (2) an objective function which relates the different outcomes from alternative release levels and harvest rates to an assessment of the degree to which individual objectives are met. The approach was used to evaluate and rank the expected outcomes from twelve proposed policies under different hypothesized ocean environments. Analysis of the results suggest that (1) the most effective policy is achieved with a relatively low harvest rate and high smolt release level; (2) selection of a particular harvest rate is the most important decision variable; and (3) a large smolt release level can be maintained unless such releases adversely decreases the ocean survival of stream spawning coho. Because the coho fishery is a mixed stock fishery consisting of hatchery and wild stocks, the results suggest that too high a harvest rate will lead to depletion of wild stocks, considered important because of their potential contribution to production and diverse genetic traits and characteristics. Conversely, too low a harvest rate will lead to excessive escapement of coho and thus reduce the total catch. As is illustrated, formulating the coho decision problem in a multiattribute utility analysis framework is useful in two ways. First, by quantifying the objectives of the decision maker, consistent results from following alternative policies can be determined. These results provide a basis for comparison and serve as a guide for decision making involving uncertainty. Second, the approach is useful in isolating major objectives and conflicts, value judgments, trade-offs, and needed empirical evidence. / Graduation date: 1982

Juvenile coho salmon (101-400 mm) were sampled by purse seine off the Pacific Coast from Waatch Point, Washington to Four Mile Creek, Oregon, out to 30 mi offshore, during the months of May, June, and September in 1982 and 1983. Sea surface temperature, surface salinity, surface chlorophyll-a concentration, and Secchi depth were measured at each station. Sea surface temperatures were higher in 1983 than in 1982, while surface chlorophyll-a concentrations and surface salinities were lower. Catch data were not highly correlated with any of the four physical parameters measured. Strong northerly winds and strong upwelling tended to disperse juvenile coho offshore and south. Fish were found closer inshore during periods of weak winds and weak upwelling. In both years the center of distribution of the fish appeared to shift northward as the summer progressed. Larger fish, in general, were found farther north and offshore throughout the year. / Graduation date: 1985

From 1998-2000, laboratory studies were conducted to examine factors that impact saltwater-entry behavior and saltwater preference (SWP) of juvenile chinook salmon, Oncorhynchus tshawytscha. These factors included bacterial kidney disease, stress and the presence of trout, O. mykiss. An additional study investigated the orientation of the startle response of chinook salmon within a salinity gradient. All experiments were conducted in 757-1 tanks in which a stable, vertical salinity gradient was established. SWP was decreased in fish suffering from bacterial kidney disease (31 �� 20.0%), compared with control fish (85 �� 17.6%). A mild chasing stressor resulted in a 26% decrease in SWP relative to unstressed fish. After a severe handling stressor, only 20% of fish preferred salt water, compared with 100% of unstressed controls. After exposure to an overhead predator model, severely stressed fish descended into the saltwater layer, but this response was transient. The presence of non-aggressive steelhead trout did not affect SWP of chinook salmon. Chinook salmon stocked with rainbow trout displayed decreased SWP. Aggression levels in tanks with rainbow trout were higher than in tanks with only chinook salmon. The orientation of the startle response was affected by the presence of salt water. Fish that preferred salt water within a gradient responded by moving horizontally within the saltwater layer. In contrast, control fish (held only in freshwater) moved vertically within the water colunm when startled. Prior preference for salt water superseded the inclination to move upward in the water column when startled. Smoltification involves physiological, behavioral and morphological changes that prepare healthy chinook salmon for seawater residence. However, disease, stress and aggressive interactions can decrease the SWP of fish at this life history stage. Avoidance of salt water during estuarine outmigration is likely maladaptive, and may have ecological ramifications including increased risk of avian predation during outmigration and decreased fitness in the marine environment. / Graduation date: 2002