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GEOGRAPHIC VARIATION IN NORTH PACIFIC HERRING POPULATIONS: PAN-PACIFIC COMPARISONS AND IMPLICATIONS FOR CLIMATE CHANGE IMPACTS Progress in Oceanography 77 (2008) 233–240 D.E. Hay, K.A. Rose, J. Schweigert , B.A. Megrey 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 geographic variation •size-at-age •spawning time •duration of the spawning period •recruitment •population diversity Methods and materialsSize-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-specific increments (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 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 East-West (weight) Mann Whitney test Latitude (length) ANOVA Results Geographic variation- Asymptotic weight western Pacific eastern 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 DiscussionIncrease 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 •gene •nutrients •continental shelf area eastern Pacific 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 Thanks for your attention !
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