1. The role of scientific knowledge to inform investors in the Blue Economy The Seychelles tuna fisheries case study
Francis Marsac, PhD
Financing Sustainable and Climate-Resilient Ocean Economies in Africa Conference Feb, Seychelles

2. KEY figures of Seychelles tuna economy
Fisheries sector accounts for 20-25% of the GDP
Fish and derived products make >90% of the exports in value
95% of those products are canned tuna
90% of WIO PS catches landed or transshipped in Victoria
>30% of WIO tunas caught in the Seychelles EEZ
49 PS vessels operating in WIO, 13 Seychelles-flagged
10% of the population depend on tuna industry and related activities

3. Outstanding transformation of port-Victoria 1970 - 2003
1983

4. Longline (deep-dwelling tunas)
Purse seine (surface dwelling tunas)
Semi-industrial
(EEZ)
Industrial
(high seas)

5. Average PS catches
The Seychelles EEZ has a strategic location in the core of the WIO purse seine fishing zone

6. The process of stock assessment
Input for the decision-making
Restrepo, ISSF
The function of Regional Fisheries Management Org.

7. A tool to summarize status of a fish stock: The Kobe diagram
Indicates the current status of a stock with respect to several reference points
Target reference points
Fmsy : Fishing mortality at the MSY
Bmsy : biomass at the MSY
Limit reference points
Blim : biomasse threshold (% of B0 or Bmsy)
Flim : fishing mortality threshold (% of Fmsy)
Management objectives :
To remain in the green quadrant
How to achieve the objectives ?
By implementing pre-agreed Harvest strategies
Overfishing Overfished
Overfishing Not overfished
No overfishing Overfished
No overfishing Not overfished
Flim
MSY
Fishing mortality ratio (F/Fmsy)
Blim
Biomass ratio (B/Bmsy)

8. Current status for Yellowfin and Skipjack
67.6%
YELLOWFIN
Current status for Yellowfin and Skipjack
Management measures : Catch reduction scheme by gear
Harvest Control Rule for Skipjack
SKIPJACK
47 %
overfishing in general has reduced revenues and economic efficiency, increased variability and reduced the resilience of stocks and catches

9. Short-term projections according to catch scenarios
Applying a catch reduction of 10% (2014 baseline), there would still be a 80 à 60% probability to remain below the biomass at MSY, at 3 and 10 years timeline respectively ;
and a 65 to 57% probability to be above the fishing mortality at MSY
Both being undesirable states

10. Average catch 1st quarter
A threat to local economies : changes in spatial distribution of catches
Average catch 1st quarter
Catch 1st quarter
1998

11. Economic impacts OF THE 1998 ANOMALY in seychelles
The relocation of the fleet to the East IO, and poor catches for several months in the WIO, substantially reduced the activity in the tuna hub of Port- Victoria (Seychelles)
Tuna industry expenditure declined by 42%
Same magnitude as the loss in Chilean and Peruvian fishmeal fisheries caused by Nino
Overall economic loss for Seychelles : 3.6% of the GDP
Robinson et al, Climate Res, 2010

12. This CHANGE IN SPATIAL PATTERN was CAUSED BY environmental anomalies
MLD
MLD
End of 1997, deeper mixed layer around Seychelles (Positive Dipole mode) and low chlorophyll made tuna less abundant and less vulnerable to the purse seine. Opposite situation occurred in the East Indian Ocean
Chlorophyll_a anomalies

13. Climate change perspective
Dramatic changes expected in the RCP 8.5 scenario (IPCC AR-5)
Increased temperature
Ocean acidification
Declining ocean productivity
Contrasts in dissolved oxygen levels
Bopp et al, 2013

14. Sketch of possible relocation of purse Seine fishing grounds during 21st Century
Seychelles may see its strategic position for PS fleets challenged by other countries
The longline gear would not be affected as much as purse seine
Favorable conditions for longline could be maintained around Seychelles
Opportunity for Seychelles-based longliners
Marsac, 2017

15. Take-home message
Robust science is necessary to empower the fisheries sector and provide advice for different governance scenarios
Well-managed fisheries (= avoiding overfishing) is a prior condition to ensure sustainability for fish stocks, economic profits and human well-being
Strong, responsible and regionally-coordinated fisheries policies
mitigate ecosystem impacts of fisheries
Environmental monitoring remains essential to adjust/adapt management measures
Physical environment and ecosystems
Different timescales to be considered
Impacts on local economies : to foresee for adaption though innovative strategies