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 History Recruitment 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 Island SSH Mean Satellite (Niiler et al. 2005)

Alaskan Stream Alaska 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 Island SSH Anomaly Satellite (AVISO) February 1998

Sablefish Recruitment 1998/02/13 Sitka Island SSH Anomaly Satellite (AVISO) strong downwelling events in the high sea level along the coast February 1998

Sablefish Recruitment 1998/02/13 Sitka Island SSH 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 Island SSH 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 Island SSH 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 Island SSH 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 Island SSH 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 Anomaly Satellite (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 Anomaly Satellite (AVISO)

Sablefish Recruitment 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 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 Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Feb 1998 Strong downwelling event high sea level anomaly Strong downwelling event high sea level anomaly ROMS eddy-resolving model hindcast from Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Mar 1998 Development of Sitka and Haida Eddies ROMS eddy-resolving model hindcast from Di 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 Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

May 1998 Sitka and Haida Eddies ROMS eddy-resolving model hindcast from Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Jun 1998 Sitka and Haida Eddies ROMS eddy-resolving model hindcast from Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Jul 1998 Sitka and Haida Eddies ROMS eddy-resolving model hindcast from Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Aug 1998 Sitka and Haida Eddies ROMS eddy-resolving model hindcast from Di Lorenzo et al. 2005; Combes et al., 2007; 2009;

Development of Sitka and Haida Eddies ROMS eddy-resolving model hindcast from Di 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 Eddy

WINTER 1998 Sitka Eddy Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Correlation Map Sitka Eddy Index vs. winter SSHa Sitka Eddy Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy

Correlation Map Sitka Eddy Index vs. winter SSHa Sitka Eddy Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy Sitka Eddy Index

Correlation Map Sitka Eddy Index vs. winter SSHa Sablefish Recruitment Sitka Eddy Index Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy Sitka Eddy

Correlation Map Sitka Eddy Index vs. winter SSHa Sablefish Recruitment Sitka Eddy Index Correlation Significance Test R=0.45 Sitka Eddy Index: average winter SSHa in formation region of Sitka Eddy Sitka Eddy

Sablefish Recruitment Sitka Eddy Index Correlation Significance Test R=0.45 Sablefish recruitment off Sitka Island and Mesoscale Circulation Hypothesis: 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.