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GEOGRAPHIC VARIATION IN NORTH PACIFIC HERRING POPULATIONS: PAN-PACIFIC
COMPARISONS AND IMPLICATIONS FOR CLIMATE CHANGE IMPACTS
Reporter : 曾建豪
D.E. Hay, K.A. Rose, J. Schweigert , B.A. Megrey
Progress in Oceanography 77 (2008) 233–240
Biological characteristic
•Depth : < 200m•Latitude : 35 °N ~ 70 °N•Spawn season : spring•Hatch : 2~3 weeks•Mature : South 2 years North 3-5 years
Introduction
fundamentalproperties
geographic variation
•size-at-age•spawning time•duration of the spawning period•recruitment•population diversity
climatefluctuations
Methods and materials- Size-at-age and fecundity data
Sources: 1. Wakefield herring symposium in 2000 2. PICES/GLOBEC symposium
•Asymptotic weight•Length at age•Fecundity data•Recruitment data•population diversity
Asymptotic weight
mean age-specific weight (g)
age-specificincrements (ASI)
of weight (g)
linear regression
Length at age
Age 5, 11populations
Age 2-14, 7populations
Data
Data
western Pacific
eastern Pacific
Fecundity data
fecundity (eggs/g) =
dividing the total egg counts (eggs)
whole body weight of spawning females (g)
Fecundity data
Gulf of Alaska
British Columbia
California
Recruitment data
BritishColumbia, Alaska, Bering Sea
coefficient of variation of annual recruitment (CVR =
mean/SD)
CVR
British Columbia, age 5
Alaska, age 5
CVR
Bering Sea, age 4
Herring population diversity
distinct populations
populations per unit of coastline
(1000km)
complexity of the coastline
Arcview Spatial Analysis
Data analyses
Latitude (length)
East-West (weight)
ANOVA
Mann Whitney test
Results Geographic variation- Asymptotic weightwestern Pacific eastern Pacific
Mann-Whitney test
Length at age
ANOVA
northernsouthern
Length at age
western Pacific
eastern Pacific
northern regions
< 0.4 populations/1000km
> 4 populations/1000km
population diversity
Population diversity
Washington State and British Columbia
Bering Sea
California
California
Area-specific recruitment
highest CVRs , greatest rangeof variability
CVR = -15.7 + 0.332 latitude
Discussion- Increase in size with latitude
•individuals smaller•lower longevity•higher relative fecundity
150 eggs/g , Gulf of Alaska
200 eggs/g , British Columbia
220 eggs/g , California
East–West differences in growth and asymptotic weight
western Pacific eastern Pacific
•nutrients
•continental shelf area
•gene
Population diversity
Sea of Okhotsk
Yellow Sea
Recruitment variation versus spawning duration
early , long
late , short
•zooplankton abundance
Recruitment variation versus spawning duration
high frequency of strongyear classes
war period (1939–1945)
Climate change impacts
sardine (Sardinops sagax), anchovy (Engraulis mordax)
smaller, non-migratory
Climate change impacts
San Diego
Santa Barbara
Thanks for your attention !