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 !