scholarly journals Survival, travel time, and utilization of Yolo Bypass, California, by outmigrating acoustic-tagged late-fall Chinook salmon

2018 ◽  
Author(s):  
Adam C. Pope ◽  
Russell W. Perry ◽  
Dalton J. Hance ◽  
Hal C. Hansel
Keyword(s):  
Travel Time ◽  
Chinook Salmon ◽  
Yolo Bypass ◽  
Late Fall

A comparison of temporal patterns in the ocean spatial distribution of California's Central Valley Chinook salmon runs

2013 ◽  
Vol 70 (4) ◽  
pp. 574-584 ◽  
Author(s):  
William H. Satterthwaite ◽  
Michael S. Mohr ◽  
Michael R. O'Farrell ◽  
Brian K. Wells
Keyword(s):  
Chinook Salmon ◽  
Sampling Error ◽  
Central Valley ◽  
Fishing Effort ◽  
Spatial Distributions ◽  
Late Fall ◽  
Unit Effort ◽  
Spatial Management ◽  
Size At Age

We developed a broadly applicable method for estimating stock-specific spatial distributions based on patterns in contacts per unit effort determined from data collected in ocean fisheries. The method fully accounts for fishing effort and quantifies uncertainty in total contacts due to sampling error and the effects of annual variability in size-at-age on estimated contacts with sublegal-sized fish. As a case study, we used coded-wire tag recoveries to compare ocean spatial distributions among fish from four return run timings (fall, late-fall, winter, and spring) of Chinook salmon from the Central Valley, California, USA, and explored how distributions varied annually, seasonally, and with fish age in the data-rich fall run. All runs were rarely contacted in ocean fisheries north of Cape Falcon, Oregon (45°46′N). Late-fall and winter run fish appeared relatively restricted to the south compared with fall run fish, corresponding to life history differences and highlighting the ability of spatial management to control impacts on the endangered winter run. For the fall run, the location of highest relative contacts per unit effort of age-3 fish varied across years. This variation correlated with sea surface temperature the previous summer, suggesting ocean distributions may be more responsive to the environment than previously appreciated.

scholarly journals Farm to Fish: Lessons from a Multi-Year Study on Agricultural Floodplain Habitat

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Ted Sommer ◽  
Brian Schreier ◽  
J. Louise Conrad ◽  
Lynn Takata ◽  
Bjarni Serup ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Central Valley ◽  
Fish Growth ◽  
Severe Drought ◽  
River Channels ◽  
Yolo Bypass ◽  
Agricultural Industry ◽  
Growth And Survival ◽  
Seasonally Flooded

Large areas of California’s historic floodplain have been separated from adjacent river channels by levee construction, allowing the development of an extensive agricultural industry. Based on successful partnerships between agriculture and conservation groups to support migrating waterfowl, we examined whether seasonally flooded rice fields could be modified to provide off-channel rearing habitat for juvenile Chinook Salmon Oncorhynchus tshawytscha. During winter and spring of 2012-2017, we conducted a series of experiments in Yolo Bypass and other regions of California’s Central Valley using hatchery Chinook Salmon as a surrogate for wild Chinook Salmon, the management target for our project. Overall, we found that seasonally flooded fields are highly productive, resulting in significantly higher levels of zooplankton and high Chinook Salmon growth rates as compared to the adjacent Sacramento River. We found similar results for multiple geographical areas in the Central Valley, and in different cover types, such as non-rice crops and fallow areas. Although field substrate type did not detectably affect fish growth and survival, connectivity with upstream and downstream areas appeared to drive fish occupancy, because rearing young salmon were generally attracted to inflow in the fields, and not all of the fish successfully emigrated off the fields without efficient drainage. In general, we faced numerous logistic and environmental challenges to complete our research. For example, periodic unmanaged floods in the Yolo Bypass made it difficult to schedule and complete experiments. During severe drought conditions, we found that managed agricultural habitats produced low and variable salmon survival results, likely because of periodically high temperatures and concentrated avian predation. In addition, our project required substantial landowner time and effort to install and maintain experimental fields. Recent and future infrastructure improvements in Yolo Bypass could substantially improve options for experimental work and broaden efforts to enhance salmon habitat.

Movements of out-migrating late-fall run Chinook salmon (Oncorhynchus tshawytscha) smolts through the San Francisco Bay Estuary

2013 ◽  
Vol 97 (8) ◽  
pp. 851-863 ◽  
Author(s):  
Alex R. Hearn ◽  
Eric D. Chapman ◽  
Gabriel P. Singer ◽  
William N. Brostoff ◽  
Peter E. LaCivita ◽  
...  
Keyword(s):  
San Francisco ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
San Francisco Bay ◽  
San Francisco Bay Estuary ◽  
Late Fall
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