scholarly journals A comparison of infectious agents between hatchery-enhanced and wild out-migrating juvenile chinook salmon (Oncorhynchus tshawytscha) from Cowichan River, British Columbia

FACETS ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 695-721 ◽  
Author(s):  
Krishna K. Thakur ◽  
Raphaël Vanderstichel ◽  
Shaorong Li ◽  
Emilie Laurin ◽  
Strahan Tucker ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Chinook Salmon ◽  
Large Scale ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
River System ◽  
Infectious Agents ◽  
Juvenile Chinook Salmon ◽  
Hatchery Fish ◽  
Juvenile Chinook

Infectious diseases are likely contributing to large-scale declines in chinook salmon stocks in the Pacific Northwest, but the specific agents and diseases involved, and the prevalences in migratory salmon, are mostly unknown. We applied a high-throughput microfluidics platform to screen for 45 infectious agents in 556 out-migrating juvenile chinook salmon, collected from freshwater (FW) and saltwater (SW) locations in the Cowichan River system on Vancouver Island, Canada, during 2014. Nineteen agents (5 bacterial, 2 viral, and 12 parasitic) were detected, with prevalences ranging from 0.2% to 57.6%. Co-infections between Candidatus Branchiomonas cysticola Toenshoff, Kvellestad, Mitchell, Steinum, Falk, Colquhoun & Horn, 2012, Paranucleospora theridion Nylund, Nylund, Watanabe, Arnesen & Kalrsbakk, 2010, and gill chlamydia, all associated with gill disease, were observed in SW samples. We detected agents known to cause large-scale mortalities in Pacific salmon ( Ceratonova shasta (Noble, 1950), Parvicapsula minibicornis Kent, Whitaker & Dawe, 1977), and agents only recently reported in Pacific salmon in BC ( Ca. B. cysticola, P. theridion, Facilispora margolisi Jones, Prosperi-Porta & Kim, 2012 and Parvicapsula pseudobranchicola Karlsbakk, Saether, Hostlund, Fjellsoy & Nylund, 2002). Wild and hatchery fish were most divergent in agent profiles in FW, with higher agent diversity in wild fish. Differences in prevalence largely dissipated once they converged in the marine environment, although hatchery fish may be infected by a greater diversity of agents sooner after ocean entry by virtue of their more rapid migration from nearshore to offshore environments.

Differential Use of the Campbell River Estuary, British Columbia by Wild and Hatchery-Reared Juvenile Chinook Salmon (Oncorhynchus tshawytscha)

1986 ◽  
Vol 43 (7) ◽  
pp. 1386-1397 ◽  
Author(s):  
C. D. Levings ◽  
C. D. McAllister ◽  
B. D. Chang
Keyword(s):  
Transition Zone ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
River Estuary ◽  
Transition Zones ◽  
Juvenile Chinook Salmon ◽  
Hatchery Fish ◽  
Mean Size ◽  
Juvenile Chinook ◽  
Marine Zone

From March 1982 to December 1983, juvenile chinook salmon (Oncorhynchus tshawytscha) were sampled by beach-seine in the Campbell River estuary and adjacent waters of Discovery Passage in order to examine estuarine use by wild and hatchery stocks. Wild juvenile chinook entered the estuary as migrant fry and were present in the estuarine zone mainly in late April to June, in the transition zone in mid-May to July, and in the marine zone in July. Hatchery fish were released from early May to early July. Maximum catches of wild stocks were similar in the estuarine and transition zones, while the maximum catches of most hatchery stocks were higher in the transition zone. For both wild and hatchery chinook, catches in the marine zone were much lower than in the estuarine and transition zones. Wild fry resided in the estuary for 40–60 d, while most hatchery fish used the estuary for about one-half this period. Wild stocks showed a relatively constant rate of increase in mean size from May to September. Higher rates of increase in the mean size of hatchery fish were shown by groups with earlier release dates and smaller mean sizes. Residency time and growth rates for wild fish were comparable with those observed in an estuary without hatchery fish. Potential for interaction between wild and hatchery stocks was greatest in the transition zone, where hatchery fish were most abundant and because hatchery releases occurred when catches of wild fish were highest in this foreshore area.

scholarly journals Juvenile Chinook salmon use of sandbar willows in a large-scale, simulated riparian floodplain: microhabitat and energetics

2021 ◽  
Author(s):  
Nann A. Fangue ◽  
Dennis E. Cocherell ◽  
Florian Mauduit ◽  
Jamilynn B. Poletto ◽  
Kara Carr ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Large Scale ◽  
River Flow ◽  
Oncorhynchus Tshawytscha ◽  
Energetic Costs ◽  
Juvenile Chinook Salmon ◽  
Consumption Rates ◽  
Floodplain Inundation ◽  
Test Velocity ◽  
Juvenile Chinook

AbstractOutmigrating, juvenile Chinook salmon Oncorhynchus tshawytscha, with access to floodplains (e.g., Yolo Bypass California, USA), grow faster than those restricted to the main channel of the Sacramento River. How these young salmon might use rooted, vegetative structure (e.g., to decrease energy expenditures) while holding positions in flowing water on floodplains and flooded riparian zones is unknown. We conducted daytime experiments in a large (24.4 m long) flume containing a planted area (9.76 m × 1.22 m) of sandbar willows, Salix interior. Flume water was maintained at 1.5 m depth and 16 °C over a 15–90 cm s−1 test velocity range. Fish were videoed using 19 cameras to determine positional behavior, including their depth, use of vegetation, and tail-beat (body-undulation) frequencies (TBFs). These TBFs were replicated with similarly-sized salmon in a calibrated, Brett-type swimming respirometer, where oxygen consumption rates were measured. Using these laboratory measurements, we estimated their swimming velocities and energetic costs associated with occupying sandbar willow habitats in the flume. As flume velocities increased and the leafy canopies of the willows were bent over from the flow, salmon occupied deeper water, among the thick stems of the willows, and maintained their positions. Even at the highest (90 cm s−1) nominal flume velocities, their estimated swimming velocities were only 35.6 cm s−1, within the bottom 15 cm of the water column. This resulted in unchanged energetic costs, compared with those estimated at lower nominal water velocities. The use of vegetated (e.g., with sandbar willow common to the riparian zone) floodplains, rather than non-vegetated ones, can potentially provide energy-saving, growth-promoting daytime habitat for migrating juvenile salmonids during river-flow periods that include floodplain inundation.

Effects of early rearing environment and breeding strategy on social interactions and the hormonal response to stressors in juvenile Chinook salmon

2015 ◽  
Vol 72 (5) ◽  
pp. 673-683 ◽  
Author(s):  
Barry N. Madison ◽  
John W. Heath ◽  
Daniel D. Heath ◽  
Nicholas J. Bernier
Keyword(s):  
Mate Choice ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Breeding Strategy ◽  
Rearing Environment ◽  
Juvenile Chinook Salmon ◽  
Hatchery Fish ◽  
The Social ◽  
Juvenile Chinook ◽  
Early Rearing

To determine whether early rearing environment and parental breeding strategy affect the social behaviour and the endocrine response to stressors in juvenile Chinook salmon (Oncorhynchus tshawytscha), offspring (1–2 g) from traditional hatchery breeding or parental mate choice breeding were reared in a hatchery setting or in seminatural channels. Once ∼30 g, 9-month-old hatchery and mate choice fish from both rearing environments were exposed to one of four treatments: (i) sampled, (ii) air-exposed (AE) for 60 s and sampled 1 h later, (iii) sampled after 5 days of continuous dyadic social interaction (SI), or (iv) AE and allowed to interact for 5 days (AE/SI). In the hatchery environment, while hatchery fish were dominant in 70% and 80% of the dyadic trials in the SI and AE/SI treatments, respectively, plasma cortisol, growth hormone, and insulin-like growth factor I levels did not differ between hatchery and mate choice fish. In contrast, when reared in a seminatural environment, mate choice fish were dominant in 70% of the dyadic trials in the SI and AE/SI treatments, and clear differences in plasma hormone levels emerged between hatchery and mate choice fish. Therefore, while we found no evidence that breeding strategy affects social status, familiarity with the early rearing environment (i.e., from emergence until 1–2 g) enhanced the competitive ability of juvenile Chinook salmon during dyadic interactions. Early rearing environment also affected the endocrine responses to stressors, and freshwater seminatural channel environments were associated with elevated hormonal responsiveness.

Costs of living for juvenile Chinook salmon (Oncorhynchus tshawytscha) in an increasingly warming and invaded world

2012 ◽  
Vol 69 (10) ◽  
pp. 1621-1630 ◽  
Author(s):  
Lauren M. Kuehne ◽  
Julian D. Olden ◽  
Jeffrey J. Duda
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
Multiple Stressors ◽  
Freshwater Ecosystems ◽  
Smallmouth Bass ◽  
Interactive Effects ◽  
Physiological Indicators ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

Rapid environmental change in freshwater ecosystems has created a need to understand the interactive effects of multiple stressors, with temperature and invasive predators identified as key threats to imperiled fish species. We tested the separate and interactive effects of water temperature and predation by non-native smallmouth bass ( Micropterus dolomieu ) on the lethal (mortality) and sublethal (behavior, physiology, and growth) effects for juvenile Chinook salmon ( Oncorhynchus tshawytscha ) in seminatural stream channel experiments. Over 48 h trials, there was no difference in direct predation with warmer temperatures, but significant interactive effects on sublethal responses of juvenile salmon. Warmer temperatures resulted in significantly stronger and more variable antipredator responses (surface shoaling and swimming activity), while physiological indicators (plasma glucose, plasma cortisol) suggested suppression of physiological mechanisms in response to the combined stressors. These patterns corresponded with additive negative growth in predation, temperature, and combined treatments. Our results suggest that chronic increases in temperature may not increase direct predation over short periods, but can result in significant sublethal costs with negative implications for long-term development, disease resistance, and subsequent size-selective mortality of Pacific salmon.

scholarly journals Comparison of Length-at-Date Criteria and Genetic Run Assignments for Juvenile Chinook Salmon Caught at Sacramento and Chipps Island in the Sacramento–San Joaquin Delta of California

2021 ◽  
Vol 19 (3) ◽  
Author(s):  
Patricia Brandes ◽  
◽  
Brian Pyper ◽  
Michael Banks ◽  
David Jacobsen ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Central Valley ◽  
River System ◽  
Population Status ◽  
Juvenile Chinook Salmon ◽  
Late Fall ◽  
San Joaquin River ◽  
Juvenile Chinook ◽  
Specific Timing

There are four distinct runs of Chinook Salmon (Oncorhynchus tshawytscha) in the Central Valley, named after their primary adult return times: fall, late-fall, winter, and spring run. Estimating the run-specific composition of juveniles entering and leaving the Sacramento–San Joaquin Delta is crucial for assessing population status and processes that affect juvenile survival through the Delta. Historically, the run of juvenile Chinook Salmon captured in the field has been determined using a length-at-date criteria (LDC); however, LDC run assignments may be inaccurate if there is high overlap in the run-specific timing and size of juveniles entering and leaving the Delta. In this study, we use genetic run assignments to assess the accuracy of LDC at two trawl locations in the Sacramento River (Delta entry) and at Chipps Island (Delta exit). Fin tissues were collected from approximately 7,500 juvenile Chinook Salmon captured in trawl samples between 2007 and 2011. Tissues were analyzed using 21 microsatellites to determine genetic run assignments for individuals, which we compared with LDC run assignments. Across years, there was extensive overlap among the distributions of run-specific fork lengths of genetically identified juveniles, indicating that run compositions based on LDC assignments would tend to underestimate fall-run and especially late-fall-run compositions at both trawl locations, and greatly overestimate spring-run compositions (both locations) and winter-run compositions (Chipps Island). We therefore strongly support ongoing efforts to include tissue sampling and genetic run identification of juvenile Chinook Salmon at key monitoring locations in the Sacramento–San Joaquin River system.

scholarly journals Managed Wetlands Can Benefit Juvenile Chinook Salmon in a Tidal Marsh

2021 ◽  
Author(s):  
Nicole M. Aha ◽  
Peter B. Moyle ◽  
Nann A. Fangue ◽  
Andrew L. Rypel ◽  
John R. Durand
Keyword(s):  
San Francisco ◽  
Growth Rates ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Nursery Habitat ◽  
San Francisco Estuary ◽  
Rice Fields ◽  
Fish Growth ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

AbstractLoss of estuarine and coastal habitats worldwide has reduced nursery habitat and function for diverse fishes, including juvenile Chinook salmon (Oncorhynchus tshawytscha). Underutilized off-channel habitats such as flooded rice fields and managed ponds present opportunities for improving rearing conditions and increasing habitat diversity along migratory corridors. While experiments in rice fields have shown enhanced growth rates of juvenile fishes, managed ponds are less studied. To evaluate the potential of these ponds as a nursery habitat, juvenile Chinook salmon (~ 2.8 g, 63 mm FL) were reared in cages in four contrasting locations within Suisun Marsh, a large wetland in the San Francisco Estuary. The locations included a natural tidal slough, a leveed tidal slough, and the inlet and outlet of a tidally muted managed pond established for waterfowl hunting. Fish growth rates differed significantly among locations, with the fastest growth occurring near the outlet in the managed pond. High zooplankton biomass at the managed pond outlet was the best correlate of salmon growth. Water temperatures in the managed pond were also cooler and less variable compared to sloughs, reducing thermal stress. The stress of low dissolved oxygen concentrations within the managed pond was likely mediated by high concentrations of zooplankton and favorable temperatures. Our findings suggest that muted tidal habitats in the San Francisco Estuary and elsewhere could be managed to promote growth and survival of juvenile salmon and other native fishes.

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