Observations On Subsurface Distributions Of Chlorophyll a And Phytoplankton Carbon In The Northeast Pacific Ocean

1974 ◽  
Vol 31 (12) ◽  
pp. 1919-1925 ◽  
Author(s):  
Louis A. Hobson ◽  
Dawn E. Ketcham
Keyword(s):  
Pacific Ocean ◽  
Chlorophyll A ◽  
Net Photosynthesis ◽  
Vancouver Island ◽  
Taxonomic Composition ◽  
Northeast Pacific ◽  
Northeast Pacific Ocean

Measurements of subsurface concentrations of chlorophyll a and phytoplankton carbon were made between Vancouver Island and Hawaii during summer 1971. In general, chlorophyll a concentrations increased and concentrations of phytoplankton carbon decreased from 10 m to depths varying between 100 and 150 m. These distributions indicated that cellular contents of chlorophyll a increased as cells were exposed to diminishing daily irradiations. Daily compensation irradiations for net photosynthesis of subsurface phytoplankton in the northeast Pacific Ocean were estimated in summer 1973. Values ranged between 0.5 and 0.7 cal cm−2 but variability among replicates was large giving a range of 0 and 1.2 cal cm−2. It was not possible to correlate compensation irradiations with taxonomic composition of phytoplankton populations.

Survey of Rockfishes, Especially Pacific Ocean Perch, in the Northeast Pacific Ocean, 1963–66

1970 ◽  
Vol 27 (10) ◽  
pp. 1781-1809 ◽  
Author(s):  
S. J. Westrheim
Keyword(s):  
Pacific Ocean ◽  
Juvenile Fish ◽  
Vancouver Island ◽  
Catch Rate ◽  
Outer Continental Shelf ◽  
Northeast Pacific ◽  
Catch Rates ◽  
Trawl Catches ◽  
Northeast Pacific Ocean ◽  
Echo Sounder

During 1963–66, a trawl and echo-sounder survey was conducted in the northeast Pacific Ocean to investigate the distribution and abundance of rockfish (Scorpaenidae) species, particularly Pacific ocean perch (Sebastodes alutus), inhabiting the outer continental shelf and upper continental slope from Cape Blanco, Oregon, to Unalaska Island, Alaska. Rockfish predominated in most trawl catches. Among areas, numbers of rockfish species declined northward, from 19–21 in the Oregon–Vancouver Island region to 5 off Unalaska Island. Within areas, maximum numbers of species were caught at intermediate depths — usually 80–139 fath (146–254 m). With rare exceptions, Pacific ocean perch was the predominant rockfish species in the trawl catches throughout the study area, although its relative abundance declined from north to south.Within areas, ocean perch catch rates were usually maximal at intermediate depths — 120–139 fath (220–254 m) in summer and substantially deeper in winter. Juvenile fish usually occupied shallower depths than adults, but were often in the company of large adults. Among areas, summer catch rates were relatively high off southwest Vancouver Island and southeastern Alaska and in the western Gulf of Alaska. Off Vancouver Island, summer catch rates were higher than winter catch rates, particularly for large adults of both sexes. Echo-sounder records indicated schools were frequently unavailable to the on-bottom trawl used in this survey.Ocean perch in the northeast Pacific Ocean were categorized, tentatively, into B.C.- and Gulf-types, whose mutual boundary is Dixon Entrance. Separation was based on differential size distributions and year-class strengths.Survival rates among year-classes were evidently quite variable, particularly for the Gulf stock west of Cape Spencer.Qualitatively, ocean perch abundance generally increased from south to north in the study area.Bottom-water temperatures varied inversely with depth and latitude. Among areas, temperature range at depths of maximal ocean perch catch rate was 4.5–7.7 C, but in high-abundance areas the temperatures did not exceed 6.0 C. Seasonally, temperature at depths of maximal catch rate varied approximately 1.5 C.

Linking phytoplankton phenology to salmon productivity along a north–south gradient in the Northeast Pacific Ocean

2015 ◽  
Vol 72 (5) ◽  
pp. 697-708 ◽  
Author(s):  
Michael J. Malick ◽  
Sean P. Cox ◽  
Franz J. Mueter ◽  
Randall M. Peterman
Keyword(s):  
Pacific Ocean ◽  
Chlorophyll A ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Regional Scale ◽  
Spatial Covariance ◽  
Covariance Functions ◽  
Northeast Pacific ◽  
Lower Productivity ◽  
Northeast Pacific Ocean

We investigated spatial and temporal components of phytoplankton dynamics in the Northeast Pacific Ocean to better understand the mechanisms linking biological oceanographic conditions to productivity of 27 pink salmon (Oncorhynchus gorbuscha) stocks. Specifically, we used spatial covariance functions in combination with multistock spawner–recruit analyses to model relationships among satellite-derived chlorophyll a concentrations, initiation date of the spring phytoplankton bloom, and salmon productivity. For all variables, positive spatial covariation was strongest at the regional scale (0–800 km) with no covariation beyond 1500 km. Spring bloom timing was significantly correlated with salmon productivity for both northern (Alaska) and southern (British Columbia) populations, although the correlations were opposite in sign. An early spring bloom was associated with higher productivity for northern populations and lower productivity for southern populations. Furthermore, the spring bloom initiation date was always a better predictor of salmon productivity than mean chlorophyll a concentration. Our results suggest that changes in spring bloom timing resulting from natural climate variability or anthropogenic climate change could potentially cause latitudinal shifts in salmon productivity.

scholarly journals Thalassiosira spp. community composition shifts in response to chemical and physical forcing in the northeast Pacific Ocean

2013 ◽  
Vol 4 ◽  
Author(s):  
P. Dreux Chappell ◽  
LeeAnn P. Whitney ◽  
Traci L. Haddock ◽  
Susanne Menden-Deuer ◽  
Eric G. Roy ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Community Composition ◽  
Physical Forcing ◽  
Northeast Pacific ◽  
Northeast Pacific Ocean

How important are coastal fronts to albacore tuna (Thunnus alalunga) habitat in the Northeast Pacific Ocean?

2017 ◽  
Vol 150 ◽  
pp. 62-71 ◽  
Author(s):  
Karen Nieto ◽  
Yi Xu ◽  
Steven L.H. Teo ◽  
Sam McClatchie ◽  
John Holmes
Keyword(s):  
Pacific Ocean ◽  
Northeast Pacific ◽  
Albacore Tuna ◽  
Thunnus Alalunga ◽  
Northeast Pacific Ocean
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