hydrodynamic connectivity in marine population dynamics satoshi mitarai 1, david a. siegel 1, bruce...

1
Hydrodynamic Connectivity in Marine Population Dynamics Satoshi Mitarai 1 , David A. Siegel 1 , Bruce E. Kendall 1 , Robert R. Warner 1 , Steven D. Gaines 1 , Christopher E. Costello 1 and Kraig B Winters 2 1 Institute for Computational Earth System Science University of California, Santa Barbara, CA 93106 2 Integrative Oceanographic Division, Scripps Institution of Oceanography, La Jolla, CA 92307 “Flow, Fish & Fishing” Project Destination location (km) Connectivity in physical space N Season #1 #2 #3 Source location (km) Spawning season #1 Spawning season #2 Spawning season #3 Three independent spawning seasons y x Mean wind Mean offshore current at surface Santa Barbara San Francisco x Target Area QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Stay near the top surface Question: Will understanding marine life cycle in turbulence improve predictablity of marine ecosystems? Habita t Harvest Regulatio n Fisherme n Market INFO Flow Fis h Settlemen t Recruitme nt Climate Flow Fish Settlement Recruitment Harves t Fisherme n Biophysical Model Role of Stochastic Connectivity in Population Dynamics # 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 (%) # of adults harvested Natural mortality Connectivity matrix Connectivity estimated from coastal circulation simulations Particles are released daily for 90 days uniformly in nearshore waters. Particles are passively transported in horizontal directions while they can actively change their vertical positions. Settlement is defined when pparticles are found in nearshore during competency window (20 to 40 d) Consider dynamics of species among sites on a long straight coastline Marine species have a two life stage (larva-adult) and a sessile adult stage Connectivity is Stochastic Connectivity is stochastic on annual time scales Larval behavior can change connectivity Stay surface Migrate 50 m + Larvae are transported by coastal eddies as coherent packets Coastal eddy motion is chaotic Only a few arriving larval packets for single spawning season Siegel et al, Proceedings of National Academy of Science (accepted for publication) Mitarai et al., Journal of Marine Systems (in press) Spatially-explicit population dynamics model We propose to examine five areas in which issues of predictability or scale render decision-making process difficult. These are the missing links in: 1. The physical drivers of larval settlement 2. The spatial scales of nearshore fish populations 3. The role of uncertainty and use of information in fishery management 4. The mismatch in scale between harvesting and regulatory decisions 5. The difficulties associated with multi-species management Smoothed out if averaged 10+ seasons Consider single unharvested species 2. Stochastic connectivity Turbulent structures exist ..... 1. Diffusion model Turbulence is ignored Diffusion model Stochasti c connectiv ity Predictions ... Mean Adult Population (%) Thoughtful experiment 1 - single species case Thoughtful experiment 2 - two species case Consider two similar species A & B Species A has a slightly better ability to utilize resources They compete for limited resources at settlement sites 1. Same Behavior 2. Different behavior A = 100 B = 0 Without difference in behavior With a difference in behavior A = 60 B = 40 Different behavior leads to species coexistence Consider single unharvested species This work is a contribution of the Flow, Fish and Fishing biocomplexity project work and is supported by the National Science Foundation (NSF grant # 0308440). Understanding marine life cycle in turbulence changes population dynamics predictions A small difference in biological processes can change community structure Sea surface temperature = Focus of this poster Density of settlers (%) Recruitment Rate Particle trajectories & sea level

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Page 1: Hydrodynamic Connectivity in Marine Population Dynamics Satoshi Mitarai 1, David A. Siegel 1, Bruce E. Kendall 1, Robert R. Warner 1, Steven D. Gaines

Hydrodynamic Connectivity in Marine Population DynamicsSatoshi Mitarai1, David A. Siegel1, Bruce E. Kendall1, Robert R. Warner1, Steven D. Gaines1, Christopher E. Costello1 and Kraig B Winters2

1Institute for Computational Earth System Science University of California, Santa Barbara, CA 93106 2Integrative Oceanographic Division, Scripps Institution of Oceanography, La Jolla, CA 92307

“Flow, Fish & Fishing” Project

Destination location (km)

Connectivity in physical space

N

Season #1 #2 #3

Sou

rce

loca

tion

(km

)

Spawning season #1

Spawning season #2

Spawning season #3

Three independent spawning seasons

y

x

Mean windMean offshore current at surface

Santa Barbara

San Franciscox

Target Area

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Stay near the top surface

Question:

Will understanding marine life cycle in turbulence improve predictablity of marine ecosystems?

Habitat

Harvest

RegulationFisherme

n

Market INFO

Flow

Fish

Settlement

Recruitment

Climate

Flow

Fish

Settlement

Recruitment

Harvest

Fishermen

Biophysical Model

Role of Stochastic Connectivity in Population Dynamics

# 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 (%)

# of adults harvestedNatural mortality Connectivity matrix

Connectivity estimated from coastal circulation simulations

Particles are released daily for 90 days uniformly in nearshore waters.

Particles are passively transported in horizontal directions while they can actively change their vertical positions.

Settlement is defined when pparticles are found in nearshore during competency window (20 to 40 d)

Consider dynamics of species among sites on a long straight coastline

Marine species have a two life stage (larva-adult) and a sessile adult stage

Connectivity is Stochastic

Connectivity is stochastic on annual time scales

Larval behavior can change connectivity

Stay surface Migrate 50 m

+

•Larvae are transported by coastal eddies as coherent packets

•Coastal eddy motion is chaotic

•Only a few arriving larval packets for single spawning season

Siegel et al, Proceedings of National Academy of Science (accepted for publication)

Mitarai et al., Journal of Marine Systems (in press)

Spatially-explicit population dynamics model We propose to examine five areas in which issues of predictability or scale render decision-making process difficult. These are the missing links in: 1. The physical drivers of larval settlement 2. The spatial scales of nearshore fish populations 3. The role of uncertainty and use of information in fishery management 4. The mismatch in scale between harvesting and regulatory decisions 5. The difficulties associated with multi-species management

Smoothed out if averaged 10+ seasons•Consider single unharvested species

2. Stochastic connectivity

Turbulent structures exist.....

1. Diffusion model

Turbulence is ignored

Diffusion model

Stochastic connectivity

Predictions

...

Mea

n A

dult

Pop

ulat

ion

(%)

Thoughtful experiment 1 - single species case

Thoughtful experiment 2 - two species case

•Consider two similar species A & B

•Species A has a slightly better ability to utilize resources They compete for limited resources at settlement sites

1. Same Behavior 2. Different behavior

A = 100

B = 0

Without difference in behavior With a difference in behavior

A = 60

B = 40

Different behavior leads to species coexistence

Consider single unharvested species

This work is a contribution of the Flow, Fish and Fishing biocomplexity project work and is supported by the National Science Foundation (NSF grant # 0308440).

•Understanding marine life cycle in turbulence changes population dynamics predictions

•A small difference in biological processes can change community structure

Sea surface temperature

=Focus of this poster

Density of settlers (%)

Rec

ruitm

ent R

ate

Particle trajectories & sea level