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 ◽  
...  
2020 ◽  
Author(s):  
Richard B. Lanman ◽  
Linda Hylkema ◽  
Cristie M. Boone ◽  
Brian Alleé ◽  
Roger O. Castillo ◽  
...  

Understanding a species’ historic range guides contemporary management and habitat restoration. Chinook salmon ( Oncorhynchus tshawytscha ) are an important commercial and recreational gamefish, but nine Chinook subspecies are federally threatened or endangered due to anthropomorphic impacts. Several San Francisco Bay Area streams and rivers currently host spawning Chinook populations, but government agencies consider these non-native hatchery strays. Using ichthyofaunal analysis of 17,288 fish specimens excavated from Native American middens at Mission Santa Clara circa 1781-1834 CE, 86 salmonid vertebrae were identified. Ancient DNA sequencing identified three of these as from Chinook salmon and the remainder from steelhead trout. These findings comprise the first physical evidence of the nativity of salmon to the Guadalupe River in San Jose, California, extending their historic range to include San Francisco Bay’s southernmost watershed.


Author(s):  
Nicole M. Aha ◽  
Peter B. Moyle ◽  
Nann A. Fangue ◽  
Andrew L. Rypel ◽  
John R. Durand

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.


Author(s):  
Catherine E. Burns ◽  
Joshua T. Ackerman ◽  
Natalie B. Washburn ◽  
Jill Bluso-Demers ◽  
Caitlin Robinson-Nilsen ◽  
...  

2010 ◽  
Vol 67 (10) ◽  
pp. 1549-1565 ◽  
Author(s):  
R. Bruce MacFarlane

The greatest rates of energy accumulation and growth in subyearling Chinook salmon ( Oncorhynchus tshawytscha ) occurred during the first month following ocean entry, supporting the importance of this critical period. Data from an 11-year study in the coastal ocean off California and the San Francisco Estuary revealed that juvenile salmon gained 3.2 kJ·day–1 and 0.8 g·day–1, representing 4.3%·day–1 and 5.2% day–1, respectively, relative to estuary exit values. Little gain in energy (0.28 kJ·day–1) or size (0.07 g·day–1) occurred in the estuary, indicating that the nursery function typically ascribed to estuaries can be deferred to initial ocean residence. Calculated northern anchovies ( Engraulis mordax ) equivalents to meet energy gains were one anchovy per day in the estuary (8% body weight·day–1) and about three per day immediately following ocean entry (15% body weight·day–1). Energy content in the estuary was positively related to higher salinity and lower freshwater outflow, whereas in the ocean, cooler temperatures, lower sea level, and greater upwelling resulted in greater gains. These results suggest that greater freshwater flows, warmer sea temperatures, and reduced or delayed upwelling, all of which are indicated by some (but not all) climate models, will likely decrease growth of juvenile Chinook salmon, leading to reduced survival.


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