280 likes | 394 Views
Progress in Oceanography 77 (2008) 233–240. D.E. Hay, K.A. Rose, J. Schweigert , B.A. Megrey. GEOGRAPHIC VARIATION IN NORTH PACIFIC HERRING POPULATIONS: PAN-PACIFIC COMPARISONS AND IMPLICATIONS FOR CLIMATE CHANGE IMPACTS. Reporter : 曾建豪. Biological characteristic. Depth : < 200m
E N D
Progress in Oceanography 77 (2008) 233–240 D.E. Hay, K.A. Rose, J. Schweigert , B.A. Megrey GEOGRAPHIC VARIATION IN NORTH PACIFIC HERRING POPULATIONS: PAN-PACIFICCOMPARISONS AND IMPLICATIONS FOR CLIMATE CHANGE IMPACTS Reporter : 曾建豪
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 climate fluctuations fundamental properties • size-at-age • spawning time • duration of the spawning period • recruitment • population diversity geographic variation
Methods and materials-Size-at-age and fecundity data Sources:1.Wakefield herringsymposium in 2000 2.PICES/GLOBECsymposium • Asymptotic weight • Length at age • Fecundity data • Recruitment data • population diversity
Asymptotic weight mean age-specific weight (g) age-specific increments (ASI) of weight (g) linear regression
Length at age Age 5, 11populations Age 2-14, 7populations
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 British Columbia, Alaska, Bering Sea coefficient of variation of annual recruitment (CVR = mean/SD)
CVR Alaska, age 5 British Columbia, age 5
CVR Bering Sea, age 4
Herring population diversity complexity of the coastline Arcview Spatial Analysis distinct populations populations per unit of coastline (1000km)
Data analyses Latitude (length) East-West (weight) Mann Whitney test ANOVA
Results Geographic variation- Asymptotic weight eastern Pacific western Pacific Mann-Whitney test
Length at age southern northern ANOVA
Length at age western Pacific eastern Pacific
Population diversity population diversity northern regions < 0.4 populations/1000km > 4 populations/1000km California Bering Sea Washington State and British Columbia California
Area-specific recruitment highest CVRs , greatest range of 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 eastern Pacific western Pacific • gene • nutrients • continental • shelf area
Population diversity Yellow Sea Sea of Okhotsk
Recruitment variation versus spawning duration late , short early , long • zooplankton abundance
Recruitment variation versus spawning duration high frequency of strong year classes war period (1939–1945)
Climate change impacts sardine (Sardinops sagax), anchovy (Engraulis mordax) smaller, non-migratory
Climate change impacts San Diego Santa Barbara