scholarly journals Foraging Behaviors of Surf Scoters and White-Winged Scoters During Spawning of Pacific Herring

The Condor ◽  
2007 ◽  
Vol 109 (1) ◽  
pp. 216-222 ◽  
Author(s):  
Tyler L. Lewis ◽  
Daniel Esler ◽  
W. Sean Boyd
Keyword(s):  
Radio Telemetry ◽  
Search Time ◽  
Early Spring ◽  
Pacific Herring ◽  
Clupea Pallasi ◽  
Melanitta Perspicillata ◽  
Courtship Behaviors ◽  
Spawning Periods ◽  
Winter Diets

Abstract Abstract Winter diets of Surf (Melanitta perspicillata) and White-winged Scoters (M. fusca) are composed primarily of bivalves. During spawning of Pacific herring (Clupea pallasi) in early spring, scoters shift their diets to herring eggs. Using radio-telemetry, we contrasted scoter foraging behaviors between winter and herring spawning periods. Scoters increased their dive durations during herring spawning, likely to maximize the amount of roe consumed per dive; in winter, dives were typically terminated upon clam capture. Scoters spent approximately 50% less time foraging (min underwater hr−1) and decreased their dive rate (dives hr−1) by 70% when feeding on roe. The observed reduction in time spent foraging was presumably caused by the abundance of herring eggs, and thus a reduction in prey search-time. Scoters were able to meet energetic requirements with reduced effort, despite potentially increased demands related to spring fattening. Less time spent foraging may also allow more time for premigratory courtship behaviors.

The Fecundity Of Pacific Herring (Clupea pallasi) in British Columbia Coastal Waters

1958 ◽  
Vol 15 (3) ◽  
pp. 313-330 ◽  
Author(s):  
Fuzuko Nagasaki
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Body Length ◽  
Coastal Waters ◽  
Early Spring ◽  
Pacific Herring ◽  
Clupea Pallasi ◽  
Relationship Of ◽  
The Relationship

The fecundity of Pacific herring was investigated from a collection of 600 ovaries gathered from various localities along the British Columbia coast during the winter and early spring of 1954–55. It was found that fecundity depended mainly on body length and to a lesser extent on age, independently of its effect on body length. Certain differences in fecundity, found between herring from various localities when die relationship of fecundity to body length was considered, were not found when the relationship between fecundity, body length and age was considered. These differences were attributed to differences in growth rate. Fecundity of herring of same body length and the same age was found to be significantly higher in northern British Columbia than in southern.

scholarly journals A review of factors limiting recovery of Pacific herring stocks in Canada

2010 ◽  
Vol 67 (9) ◽  
pp. 1903-1913 ◽  
Author(s):  
Jacob F. Schweigert ◽  
Jennifer L. Boldt ◽  
Linnea Flostrand ◽  
Jaclyn S. Cleary
Keyword(s):  
West Coast ◽  
Positive Relationship ◽  
Pacific Herring ◽  
Zooplankton Abundance ◽  
Natural Mortality ◽  
Population Recovery ◽  
The West ◽  
Clupea Pallasi ◽  
Adequate Food ◽  
Forage Species

AbstractSchweigert, J. F., Boldt, J. L., Flostrand, L., and Cleary, J. S. 2010. A review of factors limiting recovery of Pacific herring stocks in Canada. – ICES Journal of Marine Science, 67: 1903–1913. On the west coast of Canada, Pacific herring (Clupea pallasi) supported an intensive reduction fishery from the early 1930s until the collapse of all five major stocks in the late 1960s, which then recovered rapidly following a fishery closure. Despite conservative harvests, abundance has declined again recently, with little evidence of recovery. We investigated the effect of bottom-up forcing by zooplankton abundance, top-down forcing by fish and mammal predators, and the effects of sardine abundance as potential competitors on the natural mortality of the herring stock on the west coast of Vancouver Island. Herring mortality was positively related to Thysanoessa spinifera and southern chaetognaths and negatively to pteropod abundance. Estimated predation on herring decreased significantly during the years 1973–2008, with the main consumers changing from fish to mammals. However, the correlation with herring mortality was negative, whereas there was a significant positive relationship with sardine abundance. Population recovery is expected to be facilitated by a combination of factors, including adequate food supply, limited or reduced predation (including fishing), and limited competition particularly for wasp–waist systems, where different forage species may occupy similar niches.

Spatio-temporal models provide new insights on the biotic and abiotic drivers shaping Pacific Herring (Clupea pallasi) distribution

2019 ◽  
Vol 178 ◽  
pp. 102198 ◽  
Author(s):  
Martin Godefroid ◽  
Jennifer L. Boldt ◽  
James T. Thorson ◽  
Robyn Forrest ◽  
Stéphane Gauthier ◽  
...  
Keyword(s):  
Pacific Herring ◽  
Clupea Pallasi ◽  
Temporal Models ◽  
Spatio Temporal

Influence of biomass and ocean climate on the growth of Pacific herring (Clupea pallasi) from the southwest coast of Vancouver Island

1997 ◽  
Vol 54 (12) ◽  
pp. 2782-2788 ◽  
Author(s):  
R W Tanasichuk
Keyword(s):  
Growth Rates ◽  
Growing Season ◽  
Vancouver Island ◽  
Pacific Herring ◽  
Daily Growth ◽  
Sea Temperature ◽  
Clupea Pallasi ◽  
Southwest Coast ◽  
Growth Increments ◽  
Adult Growth

I examined the growth of Pacific herring (Clupea pallasi) from the southwest coast of Vancouver Island using data for over 83 000 fish seined between 1975 and 1996. Size-at-age (length, total mass) of recruits (age 3) was negatively related to parental biomass. Length was also negatively related to sea temperature over the first growing season and positively related to salinity later in the third growing season. Prerecruit effects explained variations in mass and length for adult herring ages 4 and 5, respectively. Growth of adults was described as growth increments (growth rates). Seasonal growth in length for adults was assumed to be a linear function of time, and growth in mass an exponential function. Daily growth rates for length were negatively related to initial length. Instantaneous daily growth rates in mass were a negative function of initial mass, adult biomass, and sea temperature in August. Interannual variations in condition suggest that adults grow differently in mass than they do in length. I suggest that length is not synonymous with mass as a measure of adult growth. Consequently, it provides little, if any, information on surplus energy accumulation by adults and therefore adult fish contribution to stock productivity.

Expression of viral hemorrhagic septicemia virus in prespawning Pacific herring (Clupea pallasi) exposed to weathered crude oil

1998 ◽  
Vol 55 (10) ◽  
pp. 2300-2309 ◽  
Author(s):  
M G Carls ◽  
G D Marty ◽  
T R Meyers ◽  
R E Thomas ◽  
S D Rice
Keyword(s):  
Crude Oil ◽  
Immune Surveillance ◽  
Inflammatory Cells ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Pacific Herring ◽  
Toxicant Exposure ◽  
Clupea Pallasi ◽  
Viral Hemorrhagic Septicemia ◽  
Unknown Status ◽  
Splenic Thrombosis

Expression of subclinical viral infection in response to toxicant exposure has not previously been reported, but evidence presented herein indicates that activation of viral hemorrhagic septicemia virus (VHSV) may occur in Pacific herring (Clupea pallasi) exposed to crude oil encountered after an oil spill. Decreased incidence of hepatic inflammatory cells as a function of total polynuclear aromatic hydrocarbon (TPAH) concentration was evidence for immunosuppression in exposed fish, and decreased immune surveillance is a possible mechanism by which subclinical VHSV could be reactivated. Adult Pacific herring of unknown status regarding infection by VHSV were captured from the wild and exposed to weathered crude oil for 16-18 days. TPAH concentration in tissue, VHSV prevalence, and mortality were correlated with dose. Histopathologic lesions were significantly correlated with TPAH concentration and prevalence of VHSV, but not gender or length. Significant lesions included increased hepatocellular necrosis, splenic thrombosis, and decreased inflammation in the liver.

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