2. Definition of Bycatch FIGURE 16 Definition of Bycatch CAPTURE = CATCH + BYCATCH + RELEASE

3. Relative bycatch: Bycatch/Abundance Bycatch Sp A 50,000 Bycatch Sp B 80 Abundance Sp A 5,000,000 1% Sustainable Abundance Sp B 800 10% Non-sustainable

4. 2009 incidental dolphin mortality estimates, population abundance (Gerrodette et al., 2006), and relative population mortality. Stock Incidental mortality Population abundance Relative mortality (%) Offshore spotted dolphin Northern / eastern264911,177 0.03 Southern / western254911,830 0.03 Spinner dolphin Eastern288790,613 0.04 Whitebelly222711,883 0.03 Common dolphin Northern109449,462 0.02 Central30577,048 <0.01 Southern491,525,207 <0.01 Other dolphin232,802,300 <0.01 Total1,239

5. Efficiency in resource utilization

6. a) The complement of the bycatch rate is the Utilization rate (UR), the ratio of the production of the fishery to the biomass extracted from the system from all species: Catch of a species (or group of species) UR = ------------------------------------------------------ Capture of a species (or group of species)

7. Bycatch rate (BR) = Bycatch/Capture Utilization rate = 100 – BR = Catch/Capture

8. 1993-09

10. ISSF Meeting – 24-27 Nov 09 - Sukarietta Discards by major types of fishery – FAO Kelleher Fishery discard (%) Shrimp trawl 62.3 Demersal finfish trawl 9.6 Tuna and HMS longline 28.5 Midwater (pelagic) trawl 3.4 Tuna purse seine 5.1 Mobile trap/pot 23.2 Dredge 28.3 Small pelagics purse seine 1.2 Demersal longline 7.5 Tuna pole and line 0.4

11. Expressing bycatch as the ecological cost of production Bycatch per ton of catch

12. All years (1993-2009) BYCATCH per 1000 MT of tuna BYCATCH per 1000 MT of tunaSpecies Dolphin sets School sets FAD sets FAD sets OFFSHORE SPOTTED 5.190.000.00 EASTERN SPINNER 1.990.000.00 WHITEBELLY SPINNER 1.760.000.00 COMMON DOLPHIN 1.680.040.00 OTHER DOLPHIN 0.720.050.01 SAILFISH1.783.900.18 BLACK MARLIN 0.110.250.76 STRIPED MARLIN 0.060.170.18 BLUE MARLIN 0.040.150.78 MAHI MAHI 0.8453.941,365.66 WAHOO0.563.77622.55 RAINBOW RUNNER 0.0613.64476.21 YELLOWTAIL1.25106.24116.59 OTHER SHARKS 0.683.011.71 WHITETIP SHARK 0.502.0214.10 HAMMERHEAD SHARK 0.332.495.71 UNID. SHARK 3.574.2311.06 MANTARAY4.3630.360.54 STINGRAY1.195.480.59 SILKY SHARK 7.5533.7296.59 UNID. TURTLE 0.020.070.08 OLIVE RIDLEY 0.040.130.17 GREEN/BLACK TURTLE 0.000.030.02

14. SpeciesDolphin sets Log sets OFFSHORE SPOTTED5.190.00 EASTERN SPINNER1.990.00 WHITEBELLY SPINNER1.760.00 COMMON DOLPHIN1.680.00 OTHER DOLPHIN0.720.01 SAILFISH1.780.18 BLACK MARLIN0.110.76 STRIPED MARLIN0.060.18 BLUE MARLIN0.040.78 Unid/OTHER BILLFISH0.130.27 OTHER BIG FISH0.1130.78 MAHI 0.841,365.66 WAHOO0.56622.55 RAINBOW RUNNER0.06476.21 YELLOWTAIL1.25116.59 TRIGGER FISH8.635,957.57 SILKY SHARK7.5596.59 WHITETIP SHARK0.5014.10 HAMMERHEAD SHARK0.335.71 MANTARAY4.360.54 STINGRAY1.190.59 OTHER SHARKS4.2512.77 UNID. TURTLE0.020.08 OLIVE RIDLEY0.040.17 GREEN/BLACK TURTLE0.000.02 Bycatch to produce 1000 MT tuna Average 1993-2009

15. Sets on Fish Aggreg. Devices 1 dolphin + 0.3 rays 1.4 billfishes + 30 sharks + 803 large bony fishes + 0.05 sea turtles + 18 MT tunas Sets on Dolphins

16. How to compare species? How to compare species? Conservation status Conservation status Vulnerability Vulnerability Ecological “role” (keystone, structural) Ecological “role” (keystone, structural) Trophic level Trophic level A new proposal: A new proposal: Replacement cost to the ecosystem Replacement cost to the ecosystem…………………..

18. Pinocho Moby Dick Las imagenes forman nuestra cultura

20. Bycatch/catch ratios (B/C) such as number or tonnage of a species per 1000 MT of tuna retained (Catch) are useful to link impact with production, and therefore to assess the relative ecological costs of different gears or set types. Areas and periods with high B/C ratios are good candidates for spatial or temporal closures, using Bycatch Reduction Curves (Hall, 1996).

24. Mark – recapture Satellite tracking Catch curves Fishers interviews Strandings