Northern copepod biomass anomalies and copepod species richness as indicators of trophic

structure in the NCC

Bill Peterson, Senior ScientistNOAA Fisheries

Jennifer Fisher, CIMRS/Oregon State UnivNewport OR

We have been sampling the Newport Line every two weeks for 19.5 years to try to understand:a) the causes of interannual variability in planktonb) how this variability translates into differences in food web structure upon which juvenile fish feed such as salmon, sardines, sablefish and rockfish

Circulation off thePacific Northwest

1. Subarctic Coastal Currents bringcold water and ”northern” copepodspecies to the N. California Current

2. A weak California Current,onshore flow of the West Wind Drift and Davidson Current (in winter)brings subtropical water and subtropical “southern” copepod species to the NCC = increased species richness

3. Therefore, food chain structure is affected by the source waterswhich feed the California Current

Different climate modes and associated differences in transport are important for three reasons:

Data on the abundance or biomass of ‘northern’ copepods and species richness is important because…

• Warm-water subtropical southern species- (from offshore OR and S. California) are small in size and have minimal high energy wax ester lipid depots

• Cold-water northern species – (boreal coastal species) are large and store high-energy wax esters as an over-wintering strategy

Therefore, significantly different food chains result from changes in transport

A fat _____ is a happy ______

PDO and Northern Copepod Anomaly

PDO and ONI

PD

O &

ON

I (°C)

-3

-2

-1

0

1

2

3

Biom

ass Anom

aly (Log10)

Northern Copepod Anomaly

Year

97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

PDO and Copepod Species Richness Anomaly

96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 PD

O (colors) and O

NI (line)

-3

-2

-1

0

1

2

3

4

YEAR

96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

Copepod S

peciesR

ichness Anom

aly

-6

-4

-2

0

2

4

6

8

Subtropical species

Boreal species

Copepod indices vs salmon returns

Fall ChinookR2 = 0.42; p = 0.01

excl. 2011*

Copepod Species Richness Anomaly (Log 10 May-September Average)

-4 -2 0 2 4 6

200

400

600

800

10002011Fall Chinook

R2 = 0.79; p < 0.001

Northern Copepod Biomass Anomaly

(Log10 May - September average)

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6Counts of A

dult Salm

on at Bonneville D

am(thousands; 2 year lag)

0

200

400

600

800

1000

Northern copepod anomaly (May - Sept)

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

Sa

rdine recruitm

ent (age 0)

0

5

10

15

20

25R2 = 0.65p < 0.001excl. 2003

2003

Northern copepod anomaly (May - Sept)

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

Sa

blefish recruitment

(age 0; thousa

nds)

0

10

20

30

40R2 = 0.40p = 0.01excl. 1999

1999

Northern copepod anomaly vs Sardine and Sablefish recruitment

PDO (bars) and ONI (black line)

96 98 00 02 04 06 08 10 12 14

Val

ues

(PD

O,

ON

I)

-3

-2

-1

0

1

2

3

4

Climate modes: PDO, ONI, HFCCTI, NPGO

• CC had lower flows in 03-07, and 10

• CC had higher flows in 02, 08-09 and 10-13

• Matches PDO closely(except 2014)

Howard Freelan's California Current Transport Index (Anomaly)

Year

96 98 00 02 04 06 08 10 12 14

Valu

es

-0.10

-0.05

0.00

0.05

0.10

0.15