Sablefish recruitment off Sitka

Island and Mesoscale Circulation

by A. Smith, K. Shotwell (NOAA), M. Stachura (UW) and E.

Di Lorenzo

Sablefish Recruitment

Preface: Sablefish Early Life

HistoryRecruitment is the abundance of the youngest fish entering a population that can be estimated successfully

(Myers 1998, Maunder and Watters 2003)

Very noisy timeseries

Sablefish Recruitment

Sitka Island

Mean Circulation in the Gulf of Alaska

Sablefish Recruitment

Sitka IslandSSH Mean

Satellite(Niiler et al. 2005)

Alaskan Stream A

laska Current

Sablefish Recruitment

Mean Circulation in the Gulf of Alaska

SSH Mean

Satellite(Niiler et al. 2005)

Sitka Island

Sablefish Recruitment

1998/02/13

Sitka IslandSSH Anomaly

Satellite(AVISO)

February 1998

Sablefish Recruitment

1998/02/13

Sitka IslandSSH Anomaly

Satellite(AVISO)

strong downwelling events in the high sea level along the

coast

February 1998

Sablefish Recruitment

1998/02/13

Sitka IslandSSH Anomaly

Satellite(AVISO)

strong downwelling events in the high sea level along the

coast

February 1998

stronger mesoscale Anticyclonic Eddies

9

Sablefish Recruitment

1998/03/05

Sitka IslandSSH Anomaly

Satellite(AVISO)

strong downwelling events in the high sea level along the

coast

stronger mesoscale Anticyclonic Eddies

March 1998

10

Sablefish Recruitment

1998/03/05

Sitka IslandSSH Anomaly

Satellite(AVISO)

strong downwelling events in the high sea level along the

coast

stronger mesoscale Anticyclonic Eddies

March 1998

Haida Eddies

Sitka Eddy

11

Sablefish Recruitment

1998/03/05

Sitka IslandSSH Anomaly

Satellite(AVISO)

March 1998

Haida Eddies

Sitka Eddy

Observation: Young sablefish have been found in large anticyclonic eddies in the Gulf of Alaska.Atwood et al. 2010

12

Sablefish Recruitment

1998/03/05

Sitka IslandSSH Anomaly

Satellite(AVISO)

March 1998

Haida Eddies

Sitka Eddy

Hypothesis: Higher sablefish recruit years are linked to years when large anticyclonic eddies are stronger.

Observation: Young sablefish have been found in large anticyclonic eddies in the Gulf of Alaska.Atwood et al. 2010

13

Sablefish Recruitment

1998/03/05

Sitka Island

March 1998

Sitka Eddy

Observation: Young sablefish have been found in large anticyclonic eddies in the Gulf of Alaska.

Hypothesis: Higher sablefish recruit years are linked to years when large anticyclonic eddies are stronger (e.g. Sitka Eddy).

SSH AnomalySatellite

(AVISO)

Atwood et al. 2010

14

Sablefish Recruitment

1998/03/05

Sitka Island

March 1998

Sitka Eddy

Testing the Hypothesis: Use a regional eddy-resolving ocean model hindcast (ROMS) to generate an index of Sitka Eddy strength to use as a diagnostic for predicting sablefish recruitment timeseries

SSH AnomalySatellite

(AVISO)

Sablefish RecruitmentTesting the Hypothesis: Use a regional eddy-resolving ocean model hindcast (ROMS) to generate an index of Sitka Eddy strength to use as a diagnostic for predicting sablefish recruitment timeseries

SSH Anomalies ROMS

Model

QUESTION:How does the model capture eddy events like the winter of 1998?

SSH Anomalies ROMS

Model Jan 1998

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Feb 1998

Strong downwelling eventhigh sea level anomaly

Strong downwelling eventhigh sea level anomaly

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Mar 1998

Development of Sitka and Haida Eddies

Development of Sitka and Haida Eddies

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Apr 1998

Sitka and Haida Eddies

fully developed

Sitka and Haida Eddies

fully developed

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

May 1998

Sitka and Haida Eddies

Sitka and Haida Eddies

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Jun 1998

Sitka and Haida Eddies

Sitka and Haida Eddies

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Jul 1998

Sitka and Haida Eddies

Sitka and Haida Eddies

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Aug 1998

Sitka and Haida Eddies

Sitka and Haida Eddies

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Development of Sitka and Haida Eddies

Development of Sitka and Haida Eddies

ROMS eddy-resolving model hindcast from 1950-2008Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

WINTER 1998

Sitka Eddy and Haida Eddies form in the WINTER

WINTER 1998

Sitka Eddy and Haida Eddies form in the WINTER

Sitka EddySitka Eddy

WINTER 1998

Sitka EddySitka Eddy

Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Correlation MapSitka Eddy Index vs. winter

SSHa

Sitka EddySitka Eddy

Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Correlation MapSitka Eddy Index vs. winter

SSHa

Sitka EddySitka Eddy

Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Sitka Eddy Index

Correlation MapSitka Eddy Index vs. winter

SSHa

Sablefish RecruitmentSitka Eddy Index

Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Sitka EddySitka Eddy

Correlation MapSitka Eddy Index vs. winter

SSHa

Sablefish RecruitmentSitka Eddy Index Correlation Significance

TestR=0.45

Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Sitka EddySitka Eddy

Sablefish RecruitmentSitka Eddy Index Correlation Significance

TestR=0.45

Sablefish recruitment off Sitka

Island and Mesoscale CirculationHypothesis: Higher sablefish recruit years are linked to years when Sitka eddies are stronger.This is an example of using an eddy-resolving model to generate a regional physical index to diagnose and (perhaps) predict recruitment data.