Optimal Spatial Fishery Management for the Southern California Bight

Dave Siegel, Chris Costello, Satoshi Mitarai (UCSB),

Jim McWilliams & Charles Dong (UCLA)

A Coastal Environmental Quality Initiative (CEQI) Project

A CEQI Project

• Assess optimal fishery design for SoCal Bight

• Combine established expertise in modeling

California coastal circulation (UCLA)

Larval dispersal & optimal fishery management (UCSB)

• Timeline

2007-2008, modeling larval of dispersal (awarded)

2008-2009, develop optimal fishery management (proposed)

Lagrangian Particle Tracking

• Implement Lagrangian particle tracking in ROMS by Dong and McWilliams (2007)

Single-day release from San NicholasRelease sites

Blue lines: 30-day trajectoriesRed dotes: particle positions after 30 days

Blue circles: area covered by a site (5-km radius)Particles are released every 6 hours every 1km

Lagrangian PDFs

• Computed from Lagrangian particle trajectories

From San Nicholas, as a function of travel time

Used particles released from 01/1996 to 12/1999

From 9 different sites

30-day travel time

Fishery Management

• Max {a*Stock + Profit}, for different weights, a

# of adults at x in year n+1

# of recruits to x from everywhere

# of survivors at x in year n= +

# of larvae produced at y

Fraction of larvae transported to x

Recruitment success (%)

xy

Harvesting (fishery management)

Connectivity (assessed from Lagrangian PDF)

Publications in Prep

• Mitarai et al., for JGR - Oceans

“Another Place for Physical Oceanography: Quantifying Connectivity in the Coastal Ocean”

• Watson et al., for MEPS

“Roles of larval life history and interannual variability on modeled connectivity patterns”

• Chris et al., for Science

“Optimal fishery management scenarios for the SoCal Bight”