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Residence and growth of juvenile chum salmon (Oncorhynchus keta) in Netarts Bay, OregonWilson, Matthew T. 28 February 1990 (has links)
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
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Introducing co-management at Nitinaht Lake, British ColumbiaJoseph, Robert 11 1900 (has links)
Conventional fisheries management has appeared to be at odds with the rights of Native
people in the Province of British Columbia. At the same time many Native Bands want to
focus on the salmon fishery for economic and cultural revival. The combination of these
two factors with growing management problems for the Federal Department of Fisheries
and Oceans (DFO) has, for some Bands resulted in efforts toward cooperative
management (co-management) of the resource.
This thesis analyzes the outcomes of efforts towards co-management of one Band
(Ditidaht, at Nitinaht Lake), and evaluates its effectiveness in the early stages of
implementation. The thesis includes both a literature review and a case study that
describes the Band's efforts at local control in light of their developing property rights,
made stronger by recent court cases. It also describes how the DFO has responded to
these developments, and how both groups attempted to keep the process directed toward
improved fisheries management.
The literature review reveals that while there are a number of advantages to the practice
of co-management over conventional systems, there also a number of challenges that face
local groups attempting this practice. The case study focuses particular attention on how
the Ditidaht Band has responded to these challenges.
Strategies used by the Ditidaht Band and the DFO, in response to increasing property;. .
rights of the Band, to better manage the salmon fishery and to overcome barriers to the
exercise of co-management are documented and analyzed. These strategies have
generally evolved from concern for the conservation of salmon on the part of both parties. For the Ditidaht these strategies also involved a search for economic development
opportunities.
Outcomes of the efforts of the two parties are also analyzed in terms of propositions
about co-management set out in the literature.
It is concluded that the DFO has been reluctant to grant the Ditidaht control over fisheries
management functions and appear to have done so done so reluctantly, and only as a
result of recent court cases. Because of this Ditidaht input has been kept to a minimum
and basically only involves enforcement. As for the Ditidaht Band, it has not taken full
advantage of alliances with other parties as a mechanism for enhancing its control over
the resource. The Band has also generally not responded to the importance of internal
cohesion by establishing a forum for solving disputes over allocation.
They have also failed to see the importance of using public concern for conservation as a
strategic tool. The case study highlights the importance of looking beyond short-term
interests, in this case economic development, in order to become self-sufficient in the
long-term. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
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Impacts of cumulative thermal and fishery stressors and infection development on the health and survival of adult Pacific salmon during freshwater residenceTeffer, Amy 30 April 2018 (has links)
Cumulative stressors influence the infection development, health and survival of wild Pacific salmon (Oncorhynchus spp.). Infectious disease is generally assumed to be the ultimate cause of death of wild adult salmon, but empirical evidence demonstrating links between infections and early mortality (i.e., prior to spawning) is lacking, especially as a function of cumulative migratory stressors. The influences of high river temperature and fishery capture and release on infection development and early mortality was explored in three Pacific salmon species. Adults were captured at river entry and held in freshwater tanks for the duration of river migration (days–weeks). Tank temperatures reflected either optimal (cool), warm (climate change scenario), or dynamic (changes in river temperature, behavioral thermoregulation) thermal conditions during migration. A subset of fish in all temperature groups was treated with a fishery bycatch release simulation (gillnet entanglement, air exposure) at the start of the holding period. We tracked shifts in physiology, immune activity and multiple infections using repeated biopsy (gill, blood) and molecular tools. Laboratory experiments were complimented by a telemetry study to assess impacts on behavior in the river. Novel application of high-throughput qPCR on nonlethally-sampled gill measured infections (bacteria, viruses, protozoa) concurrently with host immune gene expression, and was complemented by blood plasma chemistry to assess physiology. Ecologically relevant high temperatures increased mortality, infection development and stress metabolites and impaired host osmoregulatory function. Fishery stress reduced survival, especially after long entanglements and at high temperature, which reduced the capacity of individuals to resolve stress and infections. Females were more drastically affected, and mortality was delayed by more than a week. Fish with heavy infections in the river migrated more rapidly but traveled less distance. Sublethal effects of stressors included reduced migration rates and suppressed maturation indices that could delay maturity and extend river residence. Finally, river-exposed fish carried heavier infections and died sooner than those that bypassed the lower river, suggesting a causal influence of infections on early mortality. These findings support river-derived infections as causal factors contributing to the early mortality of adult Pacific salmon in fresh water and clarify its mechanisms, which comprise influences of multiple infections, sex, species, water temperature and fishery stress. / Graduate / 2019-04-15
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Trophic niche and foodweb dynamics within and among juvenile salmon species in years of contrasting ocean conditionsJenkins, Erica 26 September 2011 (has links)
The ecological niche of a population is dynamic and will be affected by changes in the ecosystem and as a population migrates. An ontogenetic niche shift can also occur as organisms grow and can include changes in morphology, habitat, and feeding behaviour. Although they are the two most abundant salmon species, and are further augmented through hatchery stocking, it is unclear the degree to which the niches of juvenile pink salmon (Oncorhynchus gorbuscha) and chum salmon (O. keta) overlap. Furthermore, juvenile pink salmon and chum salmon undergo a period of rapid growth during their first summer at sea and it is unclear how their ecological niche changes with their ontogeny. Understanding the foodweb dynamics of juvenile salmon in the coastal marine environment is important because a large proportion of the overall mortality of salmon is thought to occur during their first summer at sea. The purpose of this study is to determine the degree to which the niches of juvenile pink salmon and chum salmon overlap, how their trophic position and food source changes as they grow into a new ontogenetic niche, and how these processes are affected by ocean conditions.
I expected that years of poorer feeding conditions and increased competition would result in reduced trophic position and greater overlap of the niches of juvenile pink salmon and chum salmon. I hypothesized that juvenile salmon would shift their diet to a more offshore-based foodweb as they grew and that their trophic position would increase with size, but that the shift would be stronger when feeding conditions were improved.
Statistical analysis showed evidence that the overlap of the niches of pink salmon and chum salmon increased when the abundance of salmon was high. Contrary to expectations, the trophic position of salmon appeared to decrease under favourable conditions. The trophic position of both pink salmon and chum salmon was higher in the southern portion of the study area, and increased when juvenile abundance was high. I suggest that the higher trophic position among juvenile salmon when there is more competition might result from increased reliance on gelatinous zooplankton, which are carnivorous, but a nutritionally poor food choice compared to other common prey items.
The ontogenetic shift from summer to fall among juvenile salmon included a shift to a more offshore-based diet and a higher trophic position. In the northern portion of the study area, which was comprised of the southern reaches of the Alaska Coastal Current (ACC), the shift to an offshore-based food source was more pronounced than the trophic shift. In the southern portion of the study area, which included the Transition Domain (TD) between the ACC and the California Current System (CCS), the shift to a higher trophic position was more pronounced than the shift in food source.
The results of this study suggest that if climate change leads to poorer feeding conditions, the niches of pink salmon and chum salmon may increasingly overlap when the abundance of these species is high. Hatchery stocking of these species may also contribute to this trend if it leads to a greater abundance of juvenile salmon in the coastal marine environment. There is evidence that the structure of the food web and the nature of the ontogenetic niche shift are very different in the ACC and the TD, and climate change and hatchery stocking will most likely affect these regions differently. / Graduate
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Fishing for justice : an ethical framework for fisheries policies in CanadaPower, Melanie Deanne 05 1900 (has links)
Canadian fisheries are in crisis. On both the Pacific and Atlantic coasts, stories abound
of fisheries closures or failures and coastal communities in difficulty. A new approach to
fisheries policy is required, one which recognises the intrinsic value of all participants in the
fisheries ecosystem and is capable of providing guidance on how to make policy decisions. The
principles of environmental ethics provide a framework for developing justice-based fisheries
policies.
The environmental ethics literature is first explored, with special attention to fisheries
issues. From this review, a justice-based framework is identified, in which five types of justice
are viewed as pertinent to fisheries concerns. This framework is then translated into an
assessment tool, based upon the Rapfish method for rapid appraisal of fisheries and using a set
of justice-based ethical criteria. These criteria are evaluated and, through a paired comparison
survey, further explored. An assessment of a range of Canadian marine fisheries is conducted
using these ethical criteria. Subsequently, a modified Rapfish assessment, using the original
criteria supplemented with additional customised criteria, is conducted for Aboriginal fisheries
for Pacific salmon in British Columbia. Additionally, a study is conducted which explores
preferences regarding the abundance and diversity of fisheries ecosystems.
Finally, the commercial fishery for Pacific salmon in British Columbia is presented as a
case study. The Rapfish assessment results are presented, and considerations as to how to
operationalise just policies for this fishery are suggested. Recommendations include: balancing
the composition of the commercial fleet, based upon ecological impacts of the various gear
types; encouragement of local stewardship and community involvement; and inclusion of
various forms of knowledge in fisheries management and decision-making. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate
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Some effects of temperature on zygote and alevin survival, rate of development and size at hatching and emergence of Pacific salmon and rainbow troutMurray, Clyde Bruce January 1980 (has links)
This study provides comparative data on the effects of temperature on zygote and alevin survival, rate of development to 50 percent hatching and emergence, and alevin and fry size for five species of Pacific salmon (Oncorhynchus) and for rainbow trout (Salmo gairdneri). Fertilized eggs from each species were incubated in controlled temperature baths at five constant temperatures (2°, 5°, 8°, 11° and 14°C). At 2°C, survival for coho salmon zygotes was high (85 percent), moderate for sockeye salmon zygotes (40 percent) and low for chinook salmon zygotes (4 percent). No pink and chum salmon or rainbow trout zygotes survived at 2°C. However, at 14°C survival for chum salmon and rainbow trout zygotes was high (67 and 85 percent), moderate for chinook and pink salmon zygotes (50 and 55 percent) and low for sockeye salmon zygotes (10 percent). No coho salmon zygotes survived at 14°C. The same general pattern for temperature and survival holds for alevins. These data suggest that coho and sockeye salmon are adapted to lower incubation temperatures than the other species. All six species showed an inverse relationship between temperature and incubation time to 50 percent hatching and emergence. The data were analysed using linear regression but, even after a series of transformations, the relationship between temperature and development time remained curvilinear. The only exceptions were for chum salmon at hatching and pink salmon at emergence. Incubation temperature also influences both alevin and fry size. In general, low incubation temperatures produce larger alevins and fry than high incubation temperatures.
In addition to data on constant incubation temperatures, the effects of varying temperature regimes on the survival, rate of development and size of coho salmon and rainbow trout alevins and fry were also documented. Fertilized eggs from coho salmon and rainbow trout were incubated at two varying temperature regimes. The varying temperature regimes either gradually increased from 5° to 14°C (the spring regime) or gradually decreased from 14° to 5°C (the fall regime). The increasing temperature regime produces higher survival in rainbow trout zygotes and alevins than the decreasing temperature regime. However, in coho salmon there was no clear difference in zygote and alevin survival with either regime. The rate of development to hatching for zygotes incubated at either varying temperature regime was similar within a species because of similar mean incubation temperatures between regimes. But, the rate of development to emergence for alevins incubated at either varying temperature regime was different because of different mean temperatures between regimes. The linear regressions to hatching and emergence for coho salmon and rainbow trout were used to predict rates of development for zygotes and alevins incubated with each varying temperature regime. The actual and predicted rates of development to hatching and emergence are similar within a species. Varying temperature regimes also affect both alevin and fry size. The decreasing temperature regime produces larger alevins and fry in coho salmon and rainbow trout than the increasing temperature regime. / Science, Faculty of / Zoology, Department of / Graduate
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Optimal management of a transboundary fishery with specific reference to the Pacific salmonTian, Huilan, 1964- January 1998 (has links)
No description available.
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The influence of fall-spawning salmon on growth and production of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, AlaskaLang, Dirk W. 13 June 2003 (has links)
This thesis examined the influence of fall-spawning coho salmon on the
density, growth rate, body condition, and survival to outmigration of juvenile coho
salmon rearing in beaver ponds on the Copper River Delta, Alaska. During the fall of
1999 and 2000 fish rearing in ponds that received spawning salmon were compared to
ponds that did not receive spawners, and to ponds that were artificially enriched with
salmon carcasses and eggs. Juvenile coho salmon responded variably to fall-spawning
salmon. There were no consistent patterns associated with the two naturally occurring
pond types (spawning vs no spawning). In some ponds, fall-spawning salmon
increased growth rates and improved the body condition of juvenile coho salmon.
Enrichment with salmon carcasses and eggs significantly increased growth rates of
fish in non-spawning ponds. For some ponds, the relative influence of spawning and
enrichment on body condition depended on fish size. There was no evidence that the
influence of fall-spawning resulted in greater smolt production. Fall-spawning salmon
provide important food resources that can benefit juvenile coho salmon rearing in
beaver ponds on the Copper River Delta. However, other factors such as nutrients
from riparian vegetation and catchment characteristics that control hydrology and
thermal regimes are important to coho salmon smolt production. / Graduation date: 2004
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LARGE-SCALE EXOGENOUS FORCING OF LONG-TERM PACIFIC SALMON PRODUCTION AND ECOSYSTEM INTERACTIONS IN WESTERN NORTH AMERICASelbie, DANIEL 27 September 2008 (has links)
Pacific salmon (Oncorhynchus spp.) production strongly influences the ecosystems, cultures and economies of the Northeast Pacific. Historical variability in population sizes is complex, reflecting natural and human drivers. The nature and extent of such ‘exogenous’ controls on salmon and their nursery ecosystems are poorly understood, a significant impediment to sustainable fisheries management. Novel applications of paleolimnology demonstrate that past sockeye salmon abundances and nursery system ecology can be reconstructed from lake sediments. This thesis focuses on employing these techniques to establish the forcing mechanisms underlying salmon population and ecosystem dynamics, and determine the effects and interactions of fisheries management.
I provided the first reconstruction for a southern North American stock, which demonstrated the influences of both conspicuous (e.g. commercial fishery, main-stem damming) and uncertain human impacts (e.g. local damming) on endangered salmon declines. By reconstructing ecological variability at multiple trophic levels, I established that rehabilitative management (e.g. fish stocking) may have permanently altered nursery lake rearing capacity, a change potentially reinforced by recent atmospheric changes. This work highlights significant impediments to ongoing recovery efforts.
I extended my analysis of salmon management by exploring the interactive impacts of exotic salmon stocking on a remote northern lake. I demonstrated the utility of long-term data in pre-emptively understanding the complex impacts of stocking by documenting the long-term trajectories in limnological conditions. Integrating modeling, limnological and paleolimnological analyses, I determined that climate change and salmon introductions compound to alter chemical, physical and biological lake variables, ultimately altering ecosystem structure and functioning.
Finally I reconstructed salmon abundances over the past six millennia, the longest record and the first Canadian example to date, demonstrating salmon production is cyclical and far more variable than observed in the monitoring record. My analyses established that North Pacific salmon production is forced by ocean-atmospheric teleconnections ultimately linked to climatic variability in the tropical Pacific. Further analyses provided the first evidence for a possible solar forcing of Holocene salmon production on both orbital and higher frequency time scales.
Cumulatively this research improves our understanding of the processes underlying variability in Pacific salmon and their natal ecosystems, important to ecologically-informed future management. / Thesis (Ph.D, Biology) -- Queen's University, 2008-09-27 02:41:54.576
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The Resurrection of a River: The Umatilla and its SalmonShelley, Christopher Ward 01 March 2002 (has links)
Until the 1990s, salmon had been extinct from the Umatilla River for over 70 years. The struggle to bring salmon back to this river is a compelling story that exemplifies some of the new relationships in Columbia River Basin salmon management.
The Umatilla River and the disappearance of its salmon was a local issue. Irrigation interests had used the river so thoroughly it ceased to flow during the late summer and fall months-precisely when salmon needed it for migration. The Confederated Tribes of the Umatilla Indian Reservation saw decided that they would change that: they would figure out a way to put both salmon and water back into the river.
This thesis examines this process. First, it contextualizes the Umatilla River within the Columbia River Basin and Columbia Basin salmon management, and shows how a local salmon issue became a regional salmon issue. It then discusses the triangle of relationships that Indians, salmon, and hatcheries have come to form. Chapter III discusses the formation of the unique Umatilla Fish Restoration Program, which reintroduced fish into the river, and was paid for by the Bonneville Power Administration (BPA), as per the Northwest Power Act. Key elements within BPA's Fish and Wildlife Division resisted complying with the directives of the Northwest Power Planning Council to pay for the Program, setting the Program back years. I argue that this comes from two clashing ways of seeing the River: "cost-benefit analysis" versus "least cost."
Chapter IV looks at the new partnerships formed in the Umatilla River Basin by the Tribes and irrigation districts in order to encourage the U.S. Bureau of Reclamation to construct a water delivery system that would satisfy irrigators while allowing most of the Umatilla to flow freely.
The last Chapter suggests that these new and somewhat ironic partnerships between federal and state governments, private irrigators and landowners, nongovernmental organizations, and Indian tribes are key to restoring ecosystems in the Columbia River Basin. It further argues that without tribal nations playing an active role and exerting their treaty rights, restoring rivers like the Umatilla is impossible.
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