1. BY-CATCH AND DISCARDS OF THE EUROPEAN PURSE SEINE TUNA FISHERY IN THE INDIAN OCEAN. CHARACTERISTICS AND ESTIMATION FOR THE 2003-2007 PERIOD

2. AMANDE Justin Monin(1), ARIZ Javier (2), CHASSOT Emmanuel(3), CHAVANCE Pierre(3), DELGADO de Molina Alicia (2), GAERTNER Daniel(3), MUROA Hilario (4), PIANET Renaud (5), RUIZ Jon (4) 1) Centre de Recherches Océanologiques (CRO), Abidjan, Ivory Coast 2) Instituto Espanol de Oceanografia (IEO), Tenerife-Canary Island, Spain 3) Institut de Recherches pour le Développement (IRD), Centre de Recherche Halieutique Méditerranéenne et Tropicale (CRH), Sète, France 4) AZTI Tecnalia, Herrera Kaia, Portualde z :g, 20110, Pasaia (Gipuzkoa), Spain 5) Institut de Recherche pour le Développement (IRD) at Seychelles Fishing Authority (SFA), Victoria, Seychelles

3. Introduction  Importance of bycatch and discards issues  Terminology  Tuna discards (major tunas and small tunas)  Bycatch (associated species discarded or valorized)  Objectives :  Estimation  Main characteritsics Species composition Length and sex structure Utilisation

4. Data and Methods (1 of 4)  Data Collection Regulation (Reg. 1543/2000 and 1639/2001)  France (IRD), Spain (AZTI, IEO)  10 % coverage targeted  Methods (Observer programs)  Route and environment  Fishing operation  Tuna length structure tuna  Associated species biological and length characteristics  Floating device

5. Data and Methods (2 of 2)  Spain started in 2003 and France in 2005  Preparation of data. FAD, FSC, Msm (5 miles)  Extrapolation  Stratification Quarter Fishing mode (FAD, FSC, MSM) Zone ET (“Echantillonnage thonier”) Estimation for large groups of species (discarded tunas, billfishes, fishes, sharks, rays)  Confidence interval by re sampling method

6. Results Data coverage Fig 1 : Number of observed sets in the Spanish and French observer program by year and percent coverage of the total fishing effort

7. Results Data coverage Figure 2 : Observed sets by quarters and percent coverage

8. Data coverage Figure 3: Number of observed sets by type (free set BL, log set BO and submarines mounts Msm) Figure 4: Number of sets by quarters and by zone ET

9. Data coverage

10. Extrapolation Table II : By-catch estimation by species group in terms of tons, percentage and tuna production ratios Table II Species group Tuna discards FishesSharksBillfishesRays Total observed Total fishery tons3 1151 954586108205 783173 373 FAD%53,9%33,8%10,1%1,9%0,3%100,0% t/1000 t18,011,33,40,60,133,4 tons4 352914845414 577117 293 FSC%95,1%2,0%1,0% 0,9%100,0% t/1000 t37,10,80,4 0,339,0 tons12211231292 734 MsM%94,6%0,8% 1,6%2,3%100,0% t/1000 t44,60,4 0,71,147,2 tons7 5892 0466351556410 489293 401 Total%72,4%19,5%6,1%1,5%0,6%100,0% t/1000 t25,97,02,20,50,235,7

11. Total bycatch by species groups

12. Extrapolation Figure 7: Estimates of tuna discards and other by-catch by quarters for the European purse seine fishery

13. Extrapolation Figure 6: Mean by-catch (tons) and 97 % confidence intervals by species group and fishing mode

14. Extrapolation Figure 8: By-catch and discards estimation for the European purse seine fishery (raising factor based on tuna production) by zone ET

15. Total PS billfishes catch (tm)

16. Species composition according to the fishing mode

17. Total PS billfishes catch by species

18. Black marlin size distribution

19. Striped marlin size distribution

20. Sailfishes size distribution

21. Fate of caught billfishes

22. Thank you