Transcript Marine Ecology Progress Series - icess

Santa Barbara Coastal LTER &
California’s Marine Protected Areas
Dave Siegel
University of California, Santa Barbara
Santa Barbara Coastal LTER
Santa Barbara Coastal
Long Term Ecological Research
• ~ 10,000 km2
• Steep coastal
mountains
• Small estuaries
• Shallow rocky reefs
• Deep ocean basin
• Offshore islands
• Mediterranean climate
• Strong ENSO signal
• Major biogeographic boundary
Giant Kelp Forests
• Worldwide distribution on
shallow temperate reefs
• High productivity
• High species diversity
• Complex trophic interactions
• Biological habitat formation
• High economic importance
U.S. West Coast Rockfish
Source: Pacific Fisheries Management Council, 2001
How a MPA might work
• MPA’s allow adults grow to full maturity
• Elimination of harvest enables more “natural”
communities & food webs to exist
• Obvious tool for near-sedentary adults
• Fishery benefits if progeny disperse broadly
or adults “spill out” of the MPA
Fished Organism Life Cycle is Important
How a MPA might work
Spillover
MPA
Fish(x)
Distance ->
Key: Spatial Management of a Fishery
MPA’s
Work
Within
Their
Borders
From Halpern [2002]
A Benefit of Getting Old & Fat
MPA’s in Channel Islands
• State-federal process to implement Marine
Protected Areas around the Channel Island
National Marine Sanctuary
• Stakeholder driven goals:
– protect biodiversity
– maintain fishery yields & incomes
Conservation vs. Fisheries
Value
Conservation Goal
Fishery Goal
Fractional Set Aside
We were victims of public service...
• Six SBC-LTER PI’s served on the Science
Panel for the Channel Islands Marine
Reserve process
• Helped the stakeholder panel arrive on a
“preferred alternative” MPA plan
• This plan has been implemented by the
State
Approved Oct. 24, 2002 for
state waters
Federal approval in the works
What did/can SBC-LTER contribute??
• Local data & expertise
– SBC-LTER & partner program data
• Theoretical & synthetic analyses
– How big, how many, how connected?
– How hard will it be to assess MPA efficiency??
• Next steps
– Flow, Fish & Fishing (F3) Biocomplexity Project
– MLPA, California-wide MPA designation legislation
Dispersal Scales for Marine Organisms
Kinlan & Gaines [2003; Ecology 84: 2007-2020].
Larval Transport Modeling
• Provide a metric for source-to-destination
exchanges among nearshore populations
• Incorporate important oceanographic & organism
life history characteristics
• Constrain using easily obtained observations
• Useful for modeling spatial population dynamics
Siegel et al. [2003; Marine Ecology Progress Series 260: 83-96]
Larval Transport Modeling
U = 5 ustd = 15 To = 42 Tf = 56
100
total settlers= 1024 total part = 5000
90
N = 5000
80
70
60
50
40
30
20
10
0
-600
-400
-200
0
200
400
600
800
alongcoast (km) (a,b,c = 84.815 200.39 216.62)
Planktonic larval duration: 6 to 8 weeks
Flow Statistics: U = 5 cm/s, su = 15 cm/s
1000
Regional Scale Self Seeding
What fraction of larvae settle within a region
of size L?
Will a MPA seed itself
or its surroundings?
Scales as Dd/L
Dd large
L small
Dd small
L large
Will a MPA Retain or Export??
50% retention
Dd/L~0.5
Design for
Export
Design for
Conservation
A MPA will retain or export progeny based on the
organism’s dispersion scale & the size of the MPA
Is a MPA a Source or Sink?
If MPA has L= 10 km,
exports if Dd  5 km
Retains
Exports
• A single MPA will be both a larval source & sink
• Points to networks of reserves for conservation
Reserve Networks
• Enable conservation &
fisheries goals to be
achieved simultaneously
• Reserves must not be
spaced too far apart
Size --> adult movement
Spacing --> larval dispersal
Approved Oct. 24, 2002
State waters implemented
Federal in the works
Larval Transport, Time
& Fish Stock Uncertainty
• Larval dispersal calculated represents
ensemble mean conditions
• The implied time to construct this mean
estimate is ~20 years!!
– Assumes larval releases are daily & a
decorrelation time scale of 3 days
Time, continued...
• Annual recruitment may be a small sampling
of the kernel (N = 10?, or less!!)
– (300 releases / year) * (10% survival) / (3 day tL)
• Example - intermediate disperser (N = 100)
• Critical for assessing “MPA
success” as a fishery tool
1.8
total settlers= 13 total part = 100
• Implies that connections
among sites are stochastic
& intermittent
U = 5 Ustd = 15 To = 14 Tf = 21
2
N=5000
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-100
-50
0
50
100
150
alongcoast (km)
200
250
300
350
Invertebrate Settlement – SBC-LTER/PISCO
Ellwood Invert Setttlment Time Series
70
60
Mytilus
Clams (excl razor & HIAARC)
any marine snail (excl. veligers, limp)
Limpet species
Snail veliger
any seastar
Hiatella arctica
# settlers/deployment
50
40
30
20
10
0
160
180
200
220
240
JD 2001
260
280
300
320
Time series sampling – Dt = 2 d
Interpreting Settlement Time Series
• Stochastic, quasi-random time series
• No correlation of settling among species
• Few settlement events for each species
• Events are short
Ellwood Invert Setttlment Time Series
70
60
(2 days)
Mytilus
Clams (excl razor & HIAARC)
any marine snail (excl. veligers, limp)
Limpet species
Snail veliger
any seastar
Hiatella arctica
# settlers/deployment
50
40
30
20
10
0
160
180
200
220
240
JD 2001
260
280
300
320
Implications for MPA Assessment
• MPA increases in fishery yields will be difficult
to discern from inherent system variability
• A variable fishery response is expected
• Proper MPA assessment needs to be done
over some long time (not really known yet)
• Need real predictive tools (including fishing dynamics)
Flow, Fish & Fishing -
www.icess.ucsb.edu/~davey/F_cubed
MPA’s in California
• Marine Life Protection Act (AB993)
– Implement a MPA network for California
– Take a regional approach to siting marine
reserves
– SBC-LTER participants are part of this process
– On hold due to state budget
… but it is the law!!
SBC-LTER & the MPA Process
• Theoretical & synthetic analyses for MPA
– How big, how many, how connected?
– Assessment of MPA efficiency??
• Other relevant SBC results for MLPA process
– Long-term observations of the kelp ecosystem
– Terrestrial inputs of nutrients, sediments, etc.
• Our forays into the world of “broader impacts”
will continue throughout SBC’s lifespan
Thank You!!