Download presentation
Presentation is loading. Please wait.
Published byMalcolm Dennis Modified over 9 years ago
1
Temporary Octopus Fishery Closures SW Madagascar Modeling the Economic Benefits of Temporary Octopus Fisheries Closures
2
Temporary Octopus Fishery Closures SW Madagascar Modeling the Economic Benefits of Temporary Octopus Fisheries Closures Kirsten LL Oleson NREM – U. Hawai’i Tom A Oliver HIMB – U. Hawai’i Ratsimbazafy H, Benbow S, Raberinary D, Humber F Alasdair Harris Blue Ventures
4
91% of adults are fisher or gleaners Average per capita income – $1.86 (PPP)/day
5
Co-Sponsored Site Closed For Three Months Two Villages’ Octopus Fishing Grounds
6
Do village octopus closures increase catch? Do the costs of the closures pay-off economically?
7
Current Data Set 258,108 Individual Octopus 320 Mapped Fishing Sites Across 17 Villages 2004 – 2011 69 Closures in Velondriake to date Enough data in 37 of 69
8
Landings Over Time
9
Do village octopus closures increase catch? Do the costs of the closures pay-off economically?
10
Do Octopus Closures Increase Catch? Before, After, Control, Impact Framework 37 Closure Sites 37 Control Sites
11
Do Octopus Closures Increase Catch? Before, After, Control, Impact Framework 37 Closure Sites 37 Control Sites Closure (2-7 Months) Closure (2-7 Months) 37 Closure Sites 37 Control Sites 6 Weeks Before6 Weeks After No Closure
13
Control Sites: +40% (NS) Closure Sites: +423% ***
14
Landings + 5 times (kg) Landings + 5 times (kg)
16
+33% * +108% *** + 6% (NS) + 17% (NS)
17
+33% * +108% *** Catch per Unit Effort + 30 - 100% (kg/fisher-day) Catch per Unit Effort + 30 - 100% (kg/fisher-day)
18
Do Octopus Closures Increase Catch? Yes.
19
Do village octopus closures increase catch? Do the costs of the closures pay-off economically?
20
Village scale “costs”? Closure scale “costs”?
21
Village Level Octopus Fishery Revenue Closures: Clear Benefit – No Clear Fishery “Cost” Total Village-Level Revenue ($ PPP) +100% *** +8% NS Before During After
22
Closure vs. No Closure: Site–Based Cost Model Actual Closure Data Actual Closure Data Closure
23
Actual Closure Data Actual Closure Data “No Closure” Modeled From Fishery Data “No Closure” Modeled From Fishery Data Closure No Closure Closure vs. No Closure: Site–Based Cost Model
24
Actual / Simulated Closure Period > Closure Profitable if Closure vs. No Closure: Site–Based Cost Model
25
Actual / Simulated Closure Period < Closure Not Profitable if Closure vs. No Closure: Site–Based Cost Model
26
Actual / Simulated Closure Period Net Earnings (NE) How much money it will make Internal Rate of Return (IRR) How quickly it will make it Closure vs. No Closure: Site–Based Cost Model
27
Monthly Internal Rate of Return (%) Net Earnings ($ PPP) Profitability of 37 Closures (Median of 1000 Model Runs)
28
Monthly Internal Rate of Return (%) Net Earnings ($ PPP) Profitability of 37 Closures (Median of 1000 Model Runs) Not Profitable: 9/37 Profitable: 28/37 Mean NE: $450(PPP) Mean Monthly IRR: 88% Profitable: 28/37 Mean NE: $450(PPP) Mean Monthly IRR: 88%
29
Monthly Internal Rate of Return (%) Net Earnings ($ PPP) Profitability of 37 Closures (Median of 1000 Model Runs)
30
Monthly Internal Rate of Return (%) Net Earnings ($ PPP) Profitability of 37 Closures (Median of 1000 Model Runs) Not Profitable: 9/37 Profitable at 30% Monthly Discount Rate: 20/37
31
Monthly Internal Rate of Return (%) Net Earnings ($ PPP) Profitability: Effect of Illegal Catch (Median of 1000 Model Runs)
32
Illegal Catch as Percentage of Baseline Catch (%) Net Earnings ($ PPP) Effect of Illegal Catch on Net Earnings (Median of 1000 Model Runs)
33
Do the costs of the closures pay off economically? Yes. Majority of Closures Profitable: 28/37 NE: + $450 (PPP) Majority of Closures Profitable: 28/37 NE: + $450 (PPP)
34
Fisheries BenefitsEconomic Benefits Social Benefits Increased understanding of and support for community management
35
Study brought to you by: 250,000+ measured octopus 3,000+ cooperative fishers Hundreds of households Dozens of patient nahoda, informants 1,000+ hours of data collection, entry, QC Immeasurable effort of BV staff Photos courtesy of Garth Cripps Questions?: Email:koleson@hawaii.edukoleson@hawaii.edu Or: tom.andrew.oliver@gmail.comtom.andrew.oliver@gmail.com
36
Modeling Costs & Benefits: The Closure Site–Based Economic Model Actual Closure Data Actual Closure Data “No Closure” Modeled From Fishery Data “No Closure” Modeled From Fishery Data Closure Period
37
Modeling Costs & Benefits: The Closure Site–Based Economic Model Actual Closure Data Actual Closure Data “No Closure” Modeled From Fishery Data “No Closure” Modeled From Fishery Data Closure Period
38
Actual / Simulated Modeling Costs & Benefits: The Closure Site–Based Economic Model Closure Period Actual Closure Catch C
39
Actual / Simulated Modeling Costs & Benefits: The Closure Site–Based Economic Model Closure Period Modeled No Closure “Catch” NC
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.