Current Oversights in Marine Reserve Design

MARINE RESERVE DATA BASE 81 studies, 102 measurements Halpern, in press

Population Size & Productivity Increase Dramatically within Reserves

Responses Within Reserves Substantial Increases in Density, Biomass, Size & Diversity Effects of Reserve Size? –Measure of change Effectiveness Index = log[reserve/control]

smallest:.002 km 2 largest: 846 km 2 DISTRIBUTION OF RESERVE SIZES

HYPOTHETICAL RESERVE EFFECT NO EFFECT OF SIZE EFFECT VARIES WITH SIZE

RESERVE EFFECT ON DENSITY p = 0.49

RESERVE EFFECT ON BIOMASS p = 0.25

RESERVE EFFECT ON AVERAGE SIZE p = 0.95

RESERVE EFFECT ON DIVERSITY p = 0.76

The Size of Single Marine Reserves: The Challenge of Competing Interests Conservation –Persistence of populations within reserve boundaries –Larval retention is beneficial Fishing –Enhancement of production beyond reserve boundaries –Larval export is beneficial

Conservation Perspective on a Single Reserve Critical Reserve Size scales with Dispersal Distance

What is the Mean Dispersal Distance? Range for planktonic periods from 0 to 100s of days Invasions speeds from meters to 100s of km per year Genetic estimates of average dispersal –> Shanks & Grantham, Palumbi, Kinlan & Gaines

Fisheries Perspectives on Single Marine Reserves

Larger reserves may eliminate fisheries benefits

Is There a Solution to that does not Force a Compromise? Networks of Many Reserves

What is the optimal network design? How do we Design an Effective Network? We need a much better understanding of larval dispersal

Range of Solutions for Channel Islands Rank 1 30% set aside Rank 4 Rank 5Rank 2 Rank 3

Variability Among Species

Variable Circulation over Space and Time

Empiricists may Solve the Problem Otoliths as Environmental Recorders - Elemental Signatures Dissolved trace elements Larval uptake Otolithincorporation

suitable habitat Adult distribution Larval settlement Adult mortality Linking oceanic/benthic dynamics Larval distribution Larval production by adults Larval mortality Advection Diffusion Exit into adult population

Fraction Dispersal distance, km Eddy diffusivity = 16 m 2 /s Mean velocity = 1.6 cm/s Classic advection- diffusion model Estimated via flow measurements Advection versus dispersion 3 week dispersal

Alongshore Converging Eddy circulation Simple flow fields

Key Findings from Model Critical role of the Peclet Number, v 2 T/K

Year 5 Extinct by year 26Extinct by year 12 Year 5, equilibrium North to south distance along shoreline, km Percent cover of adults Year Year cm/s1 cm/s4 cm/s Year 0 Alongshore flow

Mean percent cover of adults Flow speed, cm/s Alongshore flow 40% yearly mortality 50% 60% Adult mortality rate and flow

Some possible reserve configurations Upstream reserveSystem of reservesDownstream reserve

Key Findings from Model Critical role of the Peclet Number, v 2 T/K Networks of small reserves can be much more effective than large single reserves

Year Mean percent cover of adults 1 cm/s reversing flow Upstream or downstream reserve 3-way split reserve Efficacy under intense harvest pressure 99% harvest outside reserve 60

Key Findings from Model Critical role of the Peclet Number, v 2 T/K Networks of small reserves can be much more effective than large single reserves Management of Fisheries using reserves can be more effective than managing effort

Yield/meter of habitat Percent of habitat in reserve Percent of adults collected by fishery Reserves versus quota control: Yield 1 cm/s 2 cm/s 0.5 cm/s 1 cm/s 2 cm/s 0.5 cm/s QuotaReserve system 5000

Mean percent cover of adults Percent of habitat in reserve Percent of adults collected by fishery Reserves versus quota control: Abundance 1 cm/s 2 cm/s 0.5 cm/s 1 cm/s 2 cm/s 0.5 cm/s QuotaReserve system

What is the optimal network design? How do we Design an Effective Network? We need a much better understanding of larval dispersal

Roughgarden, J., Gaines, S., and Possingham, H Science 241: suitable habitat Adult distribution Larval settlement Adult mortality Larval distribution Larval production by adults Larval mortality Advection Diffusion Exit into adult population Modeling Populations with Dispersal by Currents

Biogeographic Representation Transition Oregonian Californian

UPWELLING SYNOPTIC STATE April-May , Composite of all wind conditions Characterized by equatorward wind Weaker currents during El Nino events Impacts to species of interest: Kelpfish, Black and Yellow Rockfish

Random Solution

Connectivity in Reserve Networks Larval concentration, individuals/m2 Position alongshore, km Distance offshore, km

Year 5 Extinct by year 46 Year 5, equilibrium North to south distance along shoreline, km Percent cover of adults Year 0 10 Year cm/s1 cm/s4 cm/s Year 0 Eddy circulation Equilibrium Year 30 Flow-mediated range boundary

North to south distance along shoreline, km Percent cover of adults Reserves with alongshore flow Downstream reserve3-way split reserveUpstream reserve Year 5 Year Year 0 Year 5 Year 0 Year cm/s

Year Mean percent cover of adults 1 cm/s reversing flow Upstream reserve 3-way split No reserve Downstream Persistence in temporally variable flow