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The effect of a previous combined treatment (CO2-enriched modified atmosphere packaging, MAP and high-pressure processing, HPP, 150 MPa/5 min) on lipid stability of refrigerated (10 days/4 °C) salmon (Oncorhynchus kisutch) was studied. The following processing conditions were compared: B-0 (fish without MAP or HPP), B-1 (fish packaged under MAP and without HPP), B-2 (fish subjected to HPP without MAP) and B-3 (fish subjected to MAP and HPP). An inhibitory effect (P < 0.05) on lipid hydrolysis and oxidation was obtained by the presence of CO2 in the packaging medium; values detected at day 10 for B-0 and B-1 fish were 80.72 and 49.61 (g free fatty acids, FFA, kg−1 lipids), 6.14 and 2.81 (meq active oxygen kg−1 lipids; peroxide value), 5.05 and 3.10 (mg malondialdehyde kg−1 muscle), and 5.56 and 2.70 (fluorescence ratio), respectively. Furthermore, inhibition of lipid damage was observed for HPP alone; values detected at day 10 for B-2 fish were 76.24 (g FFA kg−1 lipids) and 5.28 (meq active oxygen kg−1 lipids). The lowest average values for lipid hydrolysis and oxidation were obtained in samples corresponding to the combined treatment (B-3 batch), differences being significant (P < 0.05) at day 10 for FFA (41.43 g kg−1 lipids), peroxide (1.84 meq kg−1 lipids) and fluorescence (2.50) values

During fish refrigerated storage, significant deterioration of sensory quality and nutritional value has been detected as a result of chemical constituent changes. Among the different recent technologies to be applied for marine food preservation, high-pressure processing (HPP) has been investigated; HPP has shown to inactivate microbial and endogenous enzymes. However, deteriorative problems have been encountered with constituents (proteins and lipids, specially) when relatively high-pressure conditions are employed. In order to lower the pressure requirement, combination of HPP with modified atmospheres technology has recently attracted a great attentio

This study focused on applying different high hydrostatic pressure + carbon dioxide (HHP + CO2) processing conditions on refrigerated (4 °C, 25 days) farmed coho salmon (Oncorhynchus kisutch) to inactivate endogenous enzymes (protease, lipase, collagenase), physicochemical properties (texture, color, lipid oxidation), and microbial shelf life. Salmon fillets were subjected to combined HHP (150 MPa/5 min) and CO2 (50%, 70%, 100%). Protease and lipase inactivation was achieved with combined HHP + CO2 treatments in which lipase activity remained low as opposed to protease activity during storage. Collagenase activity decreased approximately 90% during storage when applying HHP + CO2. Combined treatments limited the increase in spoilage indicators, such as total volatile amines and trimethylamine. The 150 MPa + 100% CO2 treatment was the most effective at maintaining hardness after 10 days of storage. Combined treatments limited HHP-induced color change and reduced the extent of changes caused by storage compared with the untreated sample. Microbial shelf life was extended by the CO2 content and not by the HHP treatments; this result was related to an increased lag phase and decreased growth rate. It can be concluded that combining HHP and CO2 could be an effective method of inactivating endogenous enzymes and extend salmon shelf life.

Monitoring the growth of salmon during their early marine phase provides insights into prey availability, and growth rates may be linked to risks of size-dependent mortality. However, the measurement of growth rate is challenging for free-living salmon in the ocean. Insulin-like growth factor (IGF)-I is a growth-promoting hormone that is emerging as a useful index of growth in salmon. In addition, laboratory-based studies using coho salmon have shown that one of circulating IGF-binding proteins (IGFBPs), IGFBP-1b, is induced by fasting and thus could be used as an inverse index of growth and/or catabolic state in salmon. However, few studies have measured plasma levels of IGFBP-1b in salmon in the wild. We measured plasma IGFBP-1b levels for postsmolt coho salmon collected in the Strait of Georgia and surrounding waters, British Columbia, Canada, and compared regional differences in IGFBP-1b to ecological information such as seawater temperature and stomach fullness. Plasma IGFBP-1b levels were the highest in fish from Eastern Johnstone Strait and relatively high in Queen Charlotte Strait and Western Johnstone Strait, which was in good agreement with the poor ocean conditions for salmon hypothesized to occur in that region. The molar ratio of plasma IGF-I to IGFBP-1b, a theoretical parameter of IGF-I availability to the receptor, discriminated differences among regions better than IGF-I or IGFBP-1b alone. Our data suggest that plasma IGFBP-1b reflects catabolic status in postsmolt coho salmon, as highlighted in fish in Eastern Johnston Strait, and is a useful tool to monitor negative aspects of salmon growth in the ocean.

Monitoring the growth of salmon during their early marine phase provides insights into prey availability, and growth rates may be linked to risks of size-dependent mortality. However, the measurement of growth rate is challenging for free-living salmon in the ocean. Insulin-like growth factor (IGF)-I is a growth-promoting hormone that is emerging as a useful index of growth in salmon. In addition, laboratory-based studies using coho salmon have shown that one of circulating IGF-binding proteins (IGFBPs), IGFBP-1b, is induced by fasting and thus could be used as an inverse index of growth and/or catabolic state in salmon. However, few studies have measured plasma levels of IGFBP-1b in salmon in the wild. We measured plasma IGFBP-1b levels for postsmolt coho salmon collected in the Strait of Georgia and surrounding waters, British Columbia, Canada, and compared regional differences in IGFBP-1b to ecological information such as seawater temperature and stomach fullness. Plasma IGFBP-1b levels were the highest in fish from Eastern Johnstone Strait and relatively high in Queen Charlotte Strait and Western Johnstone Strait, which was in good agreement with the poor ocean conditions for salmon hypothesized to occur in that region. The molar ratio of plasma IGF-I to IGFBP-1b, a theoretical parameter of IGF-I availability to the receptor, discriminated differences among regions better than IGF-I or IGFBP-1b alone. Our data suggest that plasma IGFBP-1b reflects catabolic status in postsmolt coho salmon, as highlighted in fish in Eastern Johnston Strait, and is a useful tool to monitor negative aspects of salmon growth in the ocean.

Monitoring the growth of salmon during their early marine phase provides insights into prey availability, and growth rates may be linked to risks of size-dependent mortality. However, the measurement of growth rate is challenging for free-living salmon in the ocean. Insulin-like growth factor (IGF)-I is a growth-promoting hormone that is emerging as a useful index of growth in salmon. In addition, laboratory-based studies using coho salmon have shown that one of circulating IGF-binding proteins (IGFBPs), IGFBP-1b, is induced by fasting and thus could be used as an inverse index of growth and/or catabolic state in salmon. However, few studies have measured plasma levels of IGFBP-1b in salmon in the wild. We measured plasma IGFBP-1b levels for postsmolt coho salmon collected in the Strait of Georgia and surrounding waters, British Columbia, Canada, and compared regional differences in IGFBP-1b to ecological information such as seawater temperature and stomach fullness. Plasma IGFBP-1b levels were the highest in fish from Eastern Johnstone Strait and relatively high in Queen Charlotte Strait and Western Johnstone Strait, which was in good agreement with the poor ocean conditions for salmon hypothesized to occur in that region. The molar ratio of plasma IGF-I to IGFBP-1b, a theoretical parameter of IGF-I availability to the receptor, discriminated differences among regions better than IGF-I or IGFBP-1b alone. Our data suggest that plasma IGFBP-1b reflects catabolic status in postsmolt coho salmon, as highlighted in fish in Eastern Johnston Strait, and is a useful tool to monitor negative aspects of salmon growth in the ocean.

A puzzling question in conservation biology is how to maintain overall fitness of individuals bred in captive environment upon release into the wild, especially for rehabilitating declining or threatened species [1,2]. For salmonid species, a heritable change in fitness related traits and gene expression has been reported to occur in a single generation of captivity in hatchery environment [3–5]. Such rapid changes are congruent with models of inadvertent domestication selection which may lead to maladaptation in the natural environment [4]. Arguably, the underlying mechanism by which captivity may induce fitness difference between wild and captive congeners is still poorly understood. Short- term selection on complex phenotypic traits is expected to induce subtle changes in allele frequency over multiple loci [7–9]. Yet, most studies investigating the molecular basis for rapid change in fitness related traits occurring in hatchery have concentrated their effort on 34 finding evidence for selection at the genome level by identifying loci with large effect. Numerous wild stocks of Pacific anadromous salmon and trout (genus Oncorhynchus and Salmo) have experienced fluctuating abundance over the past century, with a series of sharp declines [6–8]. With the objectives of preserving ecosystem integrity, enhancing. declining populations and sustaining fisheries, conservation hatcheries have been flourishing. This is particularly true along the North American Pacific coast where billions of salmonids, all species included, are released each year. Despite substantial improvement of production management, the beneficial ecological role of hatcheries in enhancing and restoring wild stocks is still debated, mainly because of the reduced fitness and maladaptation of hatchery-fish when released in the wild [3,5,9]. Although previous studies showed that domestication selection was involved in such fitness impairment, they also observed that different environmental

A puzzling question in conservation biology is how to maintain overall fitness of individuals bred in captive environment upon release into the wild, especially for rehabilitating declining or threatened species [1,2]. For salmonid species, a heritable change in fitness related traits and gene expression has been reported to occur in a single generation of captivity in hatchery environment [3–5]. Such rapid changes are congruent with models of inadvertent domestication selection which may lead to maladaptation in the natural environment [4]. Arguably, the underlying mechanism by which captivity may induce fitness difference between wild and captive congeners is still poorly understood. Short- term selection on complex phenotypic traits is expected to induce subtle changes in allele frequency over multiple loci [7–9]. Yet, most studies investigating the molecular basis for rapid change in fitness related traits occurring in hatchery have concentrated their effort on 34 finding evidence for selection at the genome level by identifying loci with large effect. Numerous wild stocks of Pacific anadromous salmon and trout (genus Oncorhynchus and Salmo) have experienced fluctuating abundance over the past century, with a series of sharp declines [6–8]. With the objectives of preserving ecosystem integrity, enhancing. declining populations and sustaining fisheries, conservation hatcheries have been flourishing. This is particularly true along the North American Pacific coast where billions of salmonids, all species included, are released each year. Despite substantial improvement of production management, the beneficial ecological role of hatcheries in enhancing and restoring wild stocks is still debated, mainly because of the reduced fitness and maladaptation of hatchery-fish when released in the wild [3,5,9]. Although previous studies showed that domestication selection was involved in such fitness impairment, they also observed that different environmental

A puzzling question in conservation biology is how to maintain overall fitness of individuals bred in captive environment upon release into the wild, especially for rehabilitating declining or threatened species [1,2]. For salmonid species, a heritable change in fitness related traits and gene expression has been reported to occur in a single generation of captivity in hatchery environment [3–5]. Such rapid changes are congruent with models of inadvertent domestication selection which may lead to maladaptation in the natural environment [4]. Arguably, the underlying mechanism by which captivity may induce fitness difference between wild and captive congeners is still poorly understood. Short- term selection on complex phenotypic traits is expected to induce subtle changes in allele frequency over multiple loci [7–9]. Yet, most studies investigating the molecular basis for rapid change in fitness related traits occurring in hatchery have concentrated their effort on 34 finding evidence for selection at the genome level by identifying loci with large effect. Numerous wild stocks of Pacific anadromous salmon and trout (genus Oncorhynchus and Salmo) have experienced fluctuating abundance over the past century, with a series of sharp declines [6–8]. With the objectives of preserving ecosystem integrity, enhancing. declining populations and sustaining fisheries, conservation hatcheries have been flourishing. This is particularly true along the North American Pacific coast where billions of salmonids, all species included, are released each year. Despite substantial improvement of production management, the beneficial ecological role of hatcheries in enhancing and restoring wild stocks is still debated, mainly because of the reduced fitness and maladaptation of hatchery-fish when released in the wild [3,5,9]. Although previous studies showed that domestication selection was involved in such fitness impairment, they also observed that different environmental

This work focuses on changes in sensory and physical properties of coho salmon (Oncorhynchus kisutch) during chilled storage (24 days). A marked change (p < 0.05) in the results of sensory analysis was found in the flesh of raw chilled fish (fresh odor, elasticity, hardness, oxidized odor) and in the cooked flesh of the chill-stored fish (firmness, neutral flavor, oxidized flavor, oxidized odor) samples. Additionally, physical parameters (gaping, cooking loss) also showed changes (p < 0.05) during chilled storage. According to odor and flavor descriptors (fresh odor, oxidized odor, neutral flavor), salmon fish were not acceptable after 17 days of chilled storage

Coho salmon (Oncorhynchus kisutch), also known as silver salmon, has recently acquired an important role because of its growing aquaculture production in countries such as Chile, Japan and Canada, in parallel with significant catches in countries like the United States, Russia, Canada and Japan. This thesis project focuses on this species and its derivatives products such as refrigerated, frozen, cooked and canned, susceptible of being used in the human diet. In a first phase, storage under chilled (traditional ice) and frozen (-20 °C) conditions was studied, with emphasis on the shelf life time as well as on the relative development of the various damage pathways. In a second phase, the application of different advanced technologies in order to inhibit the different mechanisms of degradation and thereby, prolong the shelf life was studied. These technologies include slurry ice, active packaging including natural antioxidants, hydrostatic high-pressure, and feeding diets enriched with natural antioxidants during the growth period. Quality indices employed throughout the development of the different experiments included chemicals and microbiological analyses, but in a special way the sensory and physical ones

The effect of a previous hydrostatic high-pressure (HHP) treatment on sensory and physical quality of chilled coho salmon (Oncorhynchus kisutch) was investigated. As a first stage, a 22 factorial design based on the response surface methodology was used for optimization of HHP conditions; for it, the effects on color uniformity, white spots appearance, elasticity, and hardness were analyzed. In a second stage, optimized HHP conditions (135 MPa for 30 s, 170 MPa for 30 s, and 200 MPa for 30 s; treatments T-1, T-2, and T-3, respectively) were applied as previous treatment to chilling, being sampling carried out on salmon muscle at days 0, 6, 10, 15, and 20. A marked effect on sensory and physical parameters was detected after HHP treatment and throughout the chilled storage. According to odor (rancid, putrid), texture (elasticity, gaping, firmness), and color (L* value) attributes, fish corresponding to T-1 condition was shown to have better-maintained quality throughout the chilled storage than fish belonging to T-2 and T-3 conditions; additionally, a quality enhancement (putrid odor, cohesivity, gaping) was found when compared with control samples. In agreement to the preliminary optimization study, it is concluded that T-1 condition can provide the most effective HHP pre-treatment to better maintain sensory and physical properties when salmon muscle is to be commercialized as a fresh product. Results obtained for the quality evolution of chilled fish attest the importance of establishing a judicious selection of previous HHP treatment parameters to minimize undesirable changes related to sensory and physical characteristics

Among the different recent technologies to be applied for marine food preservation, hydrostatic high pressure (HHP) processing has attracted great attention. HHP has shown to be profitable by inactivating microbial and endogenous enzyme activities; however, deteriorative problems have been encountered with chemical constituents, these leading to marked quality losses related to the general appearance of the product and a consumer acceptance lowering. The present work was focused on the sensory and physical changes of chilled fish that was previously treated with HHP technology. For it, farmed coho salmon (Oncorhynchus kisutch) was chosen, because of its increasing farming production and commercial interest. As previous treatment, three different HHP conditions (135 MPa-30 s; 170 MPa-30 s; 200 MPa-30 s; treatments T1, T2 and T3, respectively) were tested and compared to untreated fish (control). Sensory (rancid, amine, typical and putrid odours, colour, general aspect, hardness, cohesivity) and physical (gaping, firmness, deformation and colour) parameters were analysed on chilled muscle after 0, 6, 10, 15 and 20 days of storage. A 22 fractional factorial design was applied to identify the significant (p<0.05) variables of the HHP process. Comparison among conditions showed that control and T1 batches provided lower variations in sensory and physical properties (namely, lightness and rancidity and putrid odours) than the two other HHP conditions; indeed, the best gaping degree retention was observed in fish previously treated under T1 condition. It is concluded that T1 condition followed by chilled storage can provide an effective combination to maintain sensory and physical properties of chilled fish.

Juvenile Coho Salmon undergo many physiological changes during their springtime transformation from a freshwater parr to a migratory, seawater-capable smolt. Although field observations indicate smolts moving towards the surface and across the breadth of their streams to either swim or drift downstream with the current, water-velocity preferences of these developing cohos are unknown. Using video analysis of their swimming patterns in a calibrated, laboratory flow table with a velocity gradient, groups of three cohos generally increased their preferred water velocity through the springtime study period, to a late-May peak (daytime data, change-point regression analysis, p < 0.05) and over the entire period (nighttime data, regression analysis, p < 0.05). Moving to swifter currents should facilitate the downstream movements of these young cohos, as they develop through the parr-smolt transformation period. This information should assist managers of regulated watersheds and salmon hatcheries in optimizing juvenile salmon survival (e.g., with timely, late-spring water releases producing 0.1–0.3 m s−1 downstream water velocities).

Central California coho salmon (Oncorhynchus kisutch) are endangered and steelhead (O. mykiss) are threatened under the U.S. Endangered Species Act. As part of local monitoring efforts, Passive Integrated Transponders (PIT tags) are used in population biology and marine survival studies of these stocks. Since 2006, PIT tags have been recovered on Año Nuevo Island (ANI), an important breeding site for several species of seabirds and marine mammals. The objective of this study was to assess magnitude and effects of avian predation on juvenile salmonids in central California. Objectives were accomplished by 1) identifying predators, timing of predation, and quantifying predation using PIT tag recoveries and Mark-Recapture modeling, and 2) using behavior of a predator (the Western Gull) to examine susceptibility of juvenile salmonids to predation. Between 2006 and 2010, 252 unique PIT tags were recovered on ANI in areas that indicate Western Gulls were the primary predator depositing tags on ANI. Predation by gulls occurred during downstream migration of juvenile salmonids or immediately following ocean entry. Mark-Recapture modeling indicated PIT tags from 1-4% of tagged salmonids were deposited on ANI from watersheds in central California. Minimal temporal overlap between gulls and salmonids occurred at area watersheds, and observation of predation was rare; however, predation was 100% when overlap occurred. Predation by Western Gulls was an appreciable source of mortality for central California salmonids and should be considered in future management plans for these species.

Central California coho salmon (Oncorhynchus kisutch) are endangered and steelhead (O. mykiss) are threatened under the U.S. Endangered Species Act. As part of local monitoring efforts, Passive Integrated Transponders (PIT tags) are used in population biology and marine survival studies of these stocks. Since 2006, PIT tags have been recovered on Año Nuevo Island (ANI), an important breeding site for several species of seabirds and marine mammals. The objective of this study was to assess magnitude and effects of avian predation on juvenile salmonids in central California. Objectives were accomplished by 1) identifying predators, timing of predation, and quantifying predation using PIT tag recoveries and Mark-Recapture modeling, and 2) using behavior of a predator (the Western Gull) to examine susceptibility of juvenile salmonids to predation. Between 2006 and 2010, 252 unique PIT tags were recovered on ANI in areas that indicate Western Gulls were the primary predator depositing tags on ANI. Predation by gulls occurred during downstream migration of juvenile salmonids or immediately following ocean entry. Mark-Recapture modeling indicated PIT tags from 1-4% of tagged salmonids were deposited on ANI from watersheds in central California. Minimal temporal overlap between gulls and salmonids occurred at area watersheds, and observation of predation was rare; however, predation was 100% when overlap occurred. Predation by Western Gulls was an appreciable source of mortality for central California salmonids and should be considered in future management plans for these species.

Juvenile Coho Salmon undergo many physiological changes during their springtime transformation from a freshwater parr to a migratory, seawater-capable smolt. Although field observations indicate smolts moving towards the surface and across the breadth of their streams to either swim or drift downstream with the current, water-velocity preferences of these developing cohos are unknown. Using video analysis of their swimming patterns in a calibrated, laboratory flow table with a velocity gradient, groups of three cohos generally increased their preferred water velocity through the springtime study period, to a late-May peak (daytime data, change-point regression analysis, p < 0.05) and over the entire period (nighttime data, regression analysis, p < 0.05). Moving to swifter currents should facilitate the downstream movements of these young cohos, as they develop through the parr-smolt transformation period. This information should assist managers of regulated watersheds and salmon hatcheries in optimizing juvenile salmon survival (e.g., with timely, late-spring water releases producing 0.1–0.3 m s−1 downstream water velocities).

This work focuses the sensory and physical properties of canned farmed coho salmon (Oncorhynchus kisutch); the effect of flake ice and slurry ice as previous slaughter and chilling conditions was studied. Hydrolytic chemical changes related to sensory and physical properties were also evaluated in canned salmon. Thermal treatment led to a canned muscle showing higher firmness, lower cohesivity and colour changes (higher L* and b* values; lower a* values); filling oils showed higher turbidity scores and lower L*, a* and b* values than starting oil. Additionally, oxidised and putrid odour development in canned muscle and filling oil was low. However, previous icing condition and time (up to 9 days) provided no changes in canned muscle and filling oil, except for an increasing oxidised odour and turbidity in filling oil with chilling time. Meantime, free fatty acid formation and K value were markedly affected by previous icing system and time

This work studies the effect of a previous hydrostatic high-pressure (HHP) treatment on chilled farmed coho salmon (Oncorhynchus kisutch). Three different HHP conditions were applied (135 MPa-30 s, 170 MPa-30 s, and 200 MPa-30 s for treatments T-1, T-2, and T-3, respectively) and compared to untreated (control) fish throughout a 20-day chilled storage. Microbial activity and lipid oxidation development were analyzed. Assessment of aerobe, psychrotroph, Shewanella spp. and Pseudomonas spp. counts and trimethylamine formation showed a marked inhibitory effect (p <0.05) of HHP treatment on microbial activity, with this effect increasing with the pressure value employed. Related to lipid oxidation development, higher peroxide mean values (day 10–20 period) were found in control samples and fish treated under T-1 condition when compared to their counterparts corresponding to T-2 and T-3 treatments. On the contrary, quantification of thiobarbituric acid-reactive substances and fluorescent interaction compounds showed higher levels (p <0.05) in fish samples corresponding to T-2 and T-3 treatments. In spite of the lipid oxidation development found, polyene index and tocopherol isomer ( and ) content did not provide differences (p >0.05) as a result of previous HHP treatment

A commercial diet including synthetic antioxidants (BHT–ethoxyquin mixture) (diet I) was provided to coho salmon (Oncorhynchus kisutch) in parallel with two diets including natural antioxidants (tocopherol isomers–rich mixture, diet II; tocopherol isomers-rosemary extract mixture, diet III). A comparative study of the rancidity development in the corresponding frozen (−18 °C) products was undertaken. When compared to fish fed with diet I, individuals corresponding to diet II showed a greater (p < 0.05) retention of primary (conjugated dienes and peroxides content) and secondary (anisidine and thiobarbituric acid indices) lipid oxidation compounds that led to a lower interaction compound formation (fluorescence ratio ranges: 0.33–0.50 and 0.55–0.85, for diet II and diet I individuals, respectively); likewise, a higher polyene index (1.99–2.14 and 1.72–1.97, respectively) and lower oxidised taste scores (0.0–0.6 and 0.0–2.4, respectively) were obtained. No effect (p > 0.05) on lipid hydrolysis development (free fatty acid formation) could be found as a result of employing different diets.

A relevant farmed fish species (coho salmon; Oncorhynchus kisutch) was studied as a raw material for the canning process. The effects of preliminary chilling storage and thermal treatment (cooking and sterilisation) on the chemical constituents (lipids and non-protein nitrogen compounds) of the canned fish were analysed. An increasing previous chilling time led to an important autolysis (K value) development, and to an increasing formation of free fatty acids, and interaction compounds (fluorescence and browning assessments) (p < 0.05) in the canned product. The thermal treatment led to the formation of volatile amines (total and trimethylamine), free fatty acids, secondary lipid oxidation compounds (anisidine and thiobarbituric acid values) and interaction compounds in canned fish. Interaction compound assessment was found the most useful tool to study the lipid oxidation and non-enzymatic browning developments, while the K value showed to be an interesting index for assessing the freshness stage of the raw material employed.

Little is known about the survival of ESA-listed juvenile coho salmon during their seaward migration in the lower Klamath River. In 2006, the Bureau of Reclamation funded a study to estimate the survival of radio-tagged juvenile coho salmon in the Klamath River downstream of Iron Gate Dam. A series of models were evaluated to determine if survival varied between hatchery and wild fish and among several river reaches between the dam river kilometer 33, a total distance of 276 kilometers. The results from 2006, the first year of study, indicated little support for differences in survival between hatchery and wild fish and lower survival in the most upstream reach than in those farther downstream. This document is a brief summary of survival results to date., Prepared in cooperation with the Bureau of Reclamation. The original document contains color images.

Lipid changes related to quality loss were evaluated during frozen storage of coho salmon for up to 15 months. Biochemical indices concerning lipid hydrolysis (free fatty acids, FFA) and oxidation (peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compounds, FR; polyene index, PI) were determined and compared to sensory (odor and taste) and endogenous antioxidant (tocopherol isomers and astaxanthin) assessments. As a result of the frozen storage, lipid hydrolysis was shown to develop according to the increase in FFA content (p < 0.05). However, most biochemical lipid oxidation indices (PV, TBA-i and FR) led to a low degree of rancidity development (p < 0.05) when compared to other fatty fish species under similar frozen storage conditions. The PI value decreased (p < 0.05) at month 10 but then remained unchanged until the end of the experiment. Rancid odor and taste development were shown to be low throughout the experiment, according to the biochemical indices mentioned above. However, a progressive decrease (p < 0.05) in the original fresh odor and taste of salmon fish flesh occurred with increasing frozen storage time, such that fish samples had the poorest scores by month 15. Endogenous antioxidants were remarkably stable throughout the experiment and which might contribute to the oxidative stability of frozen farmed coho salmon lipids

Two deteriorative pathways (autolysis and microbiological activity) were studied in farmed Coho salmon (Oncorhynchus kisutch) for 24 days during chilled storage. These changes were assessed by nucleotide degradation (determination of adenosine 50-triphosphate and its degradation compounds) and biochemical (pH; content of total volatile base-nitrogen; trimethylamine-nitrogen, TMA-N; histamine) and microbial (total aerobe mesophiles, TAM; coliforms) indices related to bacterial activity. An important nucleotide degradation could be assessed according to the fast inosine 50-monophosphate formation, followed by degradation into inosine and hypoxanthine; the K value was found to be an accurate tool for the measurement of quality loss throughout the whole experiment. Regarding bacterial activity, contents of TMA-N and histamine and TAM counts assessment showed sharp increases after the end of the microbial lag phase (12– 17 days); however, values obtained for histamine content and TAM growth remained below acceptable security limits throughout the whole experiment.

Coho salmon (Oncorhynchus kisutch) is a fatty fish species whose farming production has greatly increased in recent years. Lipid damage produced during Coho salmon chilled storage was studied for up to 24 d. Lipid hydrolysis (free fatty acids, FFA) and oxidation (conjugated dienes; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compounds formation, FR; browning development) were determined and compared to lipid composition (polyene index, PI; astaxanthin, AX) changes and sensory assessment (rancid odour development) results. Most lipid damage indices developed slowly during storage; thus, values obtained for FFA, PV, TBA-i and FR were in all cases under 1.5 g/100 g, 4.0 meq oxygen/kg lipid, 0.40 mg malondialdehyde/kg muscle and 0.40, respectively. Odour assessment showed a significant (p <0.05) rancidity development at day 10, when compared to starting fish material; then, non-acceptable values were obtained at days 19 and 24. The PI analysis showed not many differences during the storage time, with the lowest mean value at day 19. AX analysis indicated a relatively high content in the white muscle, which was maintained till the end of the experiment. A low oxidation development is concluded for Coho salmon lipids when compared to other fatty fish species under the same chilling conditions. AX was found to contribute to the oxidation stability of Coho salmon lipids, due to its free radical scavenger properties

Frequently wildlife managers must decide how to allocate limited resources amongst a plurality of threatened salmon stocks. In the absence of adequate abundance data, knowledge of stocks life histories might be used to rank risk of extinction thereby allowing more efficient allocation of resources. In Chapter one I assess how differences in life histories contribute to relative risk of extinction using Pacific salmon as an example. Using simulations of coho and chinook salmon. I find increased spawning at multiple ages causes the fate of each cohort to be linked to the success of other cohorts. This novel effect I refer to as cohort coupling.Since many assume that density dependence is a stabilizing force. Chapter two examines this assumption in terms of extinction risk for coho salmon. Here again I find that life history plays a role in determining risk. along with environmental variation and quasi-extinction threshold. Key also is how density dependence is introduced into the model. I find the widely held view that density dependence is stabilizing is of limited value since density dependence can either increase or decrease probability of extinction.Chapter three explores the use of a diffusion approximation as a tool for understanding population dynamics of Pacific salmon. Diffusion approximations have a long history in ecology as models of population genetics and population growth. Modeling salmon using a diffusion approximation requires special consideration because salmon are both semelparous and anadromous. Diffusion estimates of probability of extinction are accurate only for a limited range of life histories.Since salmon exhibit environmentally influenced variability in spawning age. Chapter four explores the effect variability in spawning age has on probability of extinction. I find that when variability is confined to fraction spawning at a single age. the probability of extinction is proportional to the integrated elasticity of A. for realized fecundity

Frequently wildlife managers must decide how to allocate limited resources amongst a plurality of threatened salmon stocks. In the absence of adequate abundance data, knowledge of stocks life histories might be used to rank risk of extinction thereby allowing more efficient allocation of resources. In Chapter one I assess how differences in life histories contribute to relative risk of extinction using Pacific salmon as an example. Using simulations of coho and chinook salmon. I find increased spawning at multiple ages causes the fate of each cohort to be linked to the success of other cohorts. This novel effect I refer to as cohort coupling.Since many assume that density dependence is a stabilizing force. Chapter two examines this assumption in terms of extinction risk for coho salmon. Here again I find that life history plays a role in determining risk. along with environmental variation and quasi-extinction threshold. Key also is how density dependence is introduced into the model. I find the widely held view that density dependence is stabilizing is of limited value since density dependence can either increase or decrease probability of extinction.Chapter three explores the use of a diffusion approximation as a tool for understanding population dynamics of Pacific salmon. Diffusion approximations have a long history in ecology as models of population genetics and population growth. Modeling salmon using a diffusion approximation requires special consideration because salmon are both semelparous and anadromous. Diffusion estimates of probability of extinction are accurate only for a limited range of life histories.Since salmon exhibit environmentally influenced variability in spawning age. Chapter four explores the effect variability in spawning age has on probability of extinction. I find that when variability is confined to fraction spawning at a single age. the probability of extinction is proportional to the integrated elasticity of A. for realized fecundity

Pathogenicity of the new virus isolated from the brain of coho salmon Oncorhynchus kisutch was investigated by waterborne and intramuscular inoculation to coho salmon, masu salmon O. masou, iwana Salvelinus pluvius, steelhead trout O. mykiss, and ito Hucho perryi. Typical disease signs of spinning swimming and lethargic behavior were observed in the experimentally infected fishes. The cumulative mortality of coho salmon fry for 60 days bathed with the virus reached 6 to 34%. In intramuscular injection of the virus, cumulative mortality of coho salmon fry reached 51 to 63%. The virus also showed pathogenicity to masu salmon, steel head trout and iwana. Virus antigen was detected by indirect fluorescent antibody test (IFAT) in the kidney, brain and blood cells of the infected fish.

An undescribed virus was isolated from the brain of coho salmon (Oncorhynchus kisutch), iwana (Salvelinus pluvius), rainbow trout (O. mykiss) and ayu (Plecoglossus altivelis), and ovarian fluid of masu salmon (O. masou) cultured in the northern part of Japan. The virus was isolated from both juveniles and adult fishes. Diseased fish showed abnormal swimming movement and were lethargic. The virus replicated, inducing cytopathic effects and lysis in susceptible cell lines at temperatures of 5 to 25℃. Persistent infection was observed in several fish cell lines. The virus particles were enveloped, and were icosahedral in shape with about 80nm in diameter with a central electron-dense core. The virus was replicated with IUdR and BVdU, and inclusion bodies in the infected cells were stained with acridine orange. The virus density was 1.155g/ml and the viral RNA was 7.3kb in length. The virus was stable to pH, diethyl ether and chloroform. The virus was not neutralized by antisera against known 6 fish viruses.

Histopathological studies were made on a virus-infected coho salmon (Oncorhynchus kisutch) characterized by an abnormal swimming. Both naturally and artificially infected coho salmon showed necrosis in the kidney, including the hematopoietic elements and renal tubular epithelial cells, and also degenerative changes of melanomacrophage centers. In the brain, vacuolar degeneration with necrosis of nerve cells, congestion of blood vessels and degenerated nerve fibers were observed. By the EM, viral particles were seen in the cytoplasm of tubular cells and the macrophages in the kidney and in the axons of necrosed nerve cells in the brain.

“Objective of FY 1991: (1) Survey stream segments randomly selected in FY1990 to obtain estimates of spawning density of Oregon Coastal Natural coho salmon (OCN). (2) Estimate OCN spawning escapement in 1900-91 using Stratified Random Sampling (SRS). (3) Determine the precision of the 1990-91 OCN spawning escapment estimate derives from SRS. (4) Compare the spawning density of OCN coho salmon in 1990-91 in standard of SRS survey sites. (5) Improve the accuracy of our database of OCN spawning habitat. (6) Allocate and select SRS sites for estimating OCN spawning density during the 1991-92 spawning (FY 1992).”

The Little White Salmon National Fish Hatchery was built in 1896 to supplement the run of tule fall chinook salmon (Oncorhynchus tshawytscha). In succeeding years other species of salmon and trout were reared but coho salmon (0. kisutch) was the only species that established a dependable run. This report is documentation of the changes in fish culture objectives, methods, and stocks during the past 90 years by presenting the history of the Little White Salmon National Fish Hatchery (NFH). Primary sources of data include the daily logs and annual reports.

“Objective of FY 1991: (1) Survey stream segments randomly selected in FY1990 to obtain estimates of spawning density of Oregon Coastal Natural coho salmon (OCN). (2) Estimate OCN spawning escapement in 1900-91 using Stratified Random Sampling (SRS). (3) Determine the precision of the 1990-91 OCN spawning escapment estimate derives from SRS. (4) Compare the spawning density of OCN coho salmon in 1990-91 in standard of SRS survey sites. (5) Improve the accuracy of our database of OCN spawning habitat. (6) Allocate and select SRS sites for estimating OCN spawning density during the 1991-92 spawning (FY 1992).”

This Species Profile of the coho salmon (Oncorhynchus kisutch) is designed to give background material on virtually all aspects of the fish's life history. The coho is anadromous, swimming upstream from the ocean in fall to spawn. The fry hatch in the spring and outmigrate 1 to 2 years later. They usually spend two growing seasons at sea. They require clear, cold, well-oxygenated (4 mg/1) stream water (1 m/sec) for spawning and rearing, with a gravel substrate, adequate cover, and a food supply of insects, crustaceans, and fishes for the young. All populations of coho salmon are limited by the amount of suitable rearing area available. They are sought after in both sport and commercial fisheries, and are very sensitive, especially the early life stages in streams, to such human-made impacts as siltation, pollution, removal of cover, and barriers to migration. Current management objectives of the State of Washington are toward MSH (maximum sustained harvest), with the treaty Indian tribes under the Boldt Decision (United States vs. State of Washington) having a legal right to 50% of the catchable allocation. Keywords: Feeding habits, Animal migrations, Life cycles, Growth.

Flow through bioassays were performed on smolting juvenile coho salmon with sediment from inner areas of Grays Harbor estuary. Previous work has shown that heavy metals have the ability to impair osmoregulatory capacity. Fish were exposed to these sediments for 9 days and then placed in seawater for 24 hours. Dredging activities occurring in the inner portion of Grays Harbor are not believed to be causing impairment of migrating smolts., Report on Grays Harbor Navigation Project Operations and Maintenance.

A review and synthesis of existing information were used to develop a riverine habitat model for Coho Salmon (Oncorhychus kitsutch) an anadromous species. The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitable habitat) for riverine areas of the continental United States. Habitat suitability indices (HSI's) are designed for use with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. p38

Given changing climatic conditions in British Columbia, Canada, there is a need to examine the hydrologic regime in freshwater systems and the potential implications of a changing regime to species in these systems. This study assessed parameters in the Telkwa River (TR) watershed which, if altered, could potentially have adverse effects on the TR's hydrologic regime and juvenile Pacific coho salmon (Oncorhynchus kisutch). Current and historic parameters, including: local climate; glacier mass; discharge; water temperature; and the characteristics of adjacent wetland and off-channel habitats (WOHs) utilized by O. kisutch were examined. It was found that long-term changes to local climate are having an impact on the hydrologic regime by reducing glacier mass, and altering intra-annual and annual discharge. However, with respect to WOHs, a significant ecological change in response to the altered hydrologic regime was not noted, suggesting WOHs have been capable of buffering the changing hydrologic conditions to date.

Coastal cutthroat trout (Oncorhynchus clarkii clarkii) are the apex predator in the Capilano Reservoir. This thesis investigates cutthroat predation via bioenergetic modelling and demography, and genetic analysis of hybridization with coastal rainbow / steelhead trout (O. mykiss irideus). The bioenergetics model, based on stomach content analyses, reservoir temperature and growth rates, in conjunction with predator abundance, estimates that adult trout in the reservoir consumed 6.4% of coho (O. kisutch) smolt production in 2010. No evidence of cutthroat predation on juvenile steelhead out-migrants was detected, and a gape prey maximum of 36% of predator body length was found. Moderate hybridization rates between cutthroat and rainbow trout were detected, as well as previously unknown pure strains of adult rainbow trout in reservoir waters, indicating reservoir residualization. Cutthroat trout are currently a 'second tier' management species in the Capilano Watershed, and greater understanding and appreciation of their adfluvial-lacustrine life history will facilitate informed decision-making for trout conservation and restoration, and coho management in the reservoir and the Capilano Watershed.

Coastal cutthroat trout (Oncorhynchus clarkii clarkii) are the apex predator in the Capilano Reservoir. This thesis investigates cutthroat predation via bioenergetic modelling and demography, and genetic analysis of hybridization with coastal rainbow / steelhead trout (O. mykiss irideus). The bioenergetics model, based on stomach content analyses, reservoir temperature and growth rates, in conjunction with predator abundance, estimates that adult trout in the reservoir consumed 6.4% of coho (O. kisutch) smolt production in 2010. No evidence of cutthroat predation on juvenile steelhead out-migrants was detected, and a gape prey maximum of 36% of predator body length was found. Moderate hybridization rates between cutthroat and rainbow trout were detected, as well as previously unknown pure strains of adult rainbow trout in reservoir waters, indicating reservoir residualization. Cutthroat trout are currently a 'second tier' management species in the Capilano Watershed, and greater understanding and appreciation of their adfluvial-lacustrine life history will facilitate informed decision-making for trout conservation and restoration, and coho management in the reservoir and the Capilano Watershed.