1. New insights on Reproductive strategy of swordfish (Xiphias gladius)
In the Southwestern Indian OCean
F.Poisson. Fauvel C.

2. Part 2: Fecundity and spawning pattern

3. Close to over-exploitation (IOTC)
35,000 Tonnes
1990

4. Aims of this study
Monitor the gonadal development of individuals around Reunion Island,
Review all information available in the Indian and western Pacific Oceans.

5. Sampling program Over 32 CONSECUTIVE MONTHS
52 trips onboard domestic longliners
294 days at sea, 235 longline sets
1727 gonads sampled

6. Spawning occurs from October to April
Gonadal Index (Hinton et al. 1996)
Spawning
Threshold value
1.375

7. Spawning season is longer for bigger (older) females

8. The Big individuals arrived at the beginning of the Spawning season

9. Sex ratio fluctuated seasonaly according to SST

10. Batch fecundity increases with the fish weight (age)
Millions of oocytes

11. Big Old Fat Fecund Female Fish
Big Old Fat Fecund Female Fish (BOFFFF) hypothesis (Longhurst 2002, Berkeley et al. 2004)
Diameter of eggs ☺ ☺
offsprings Viability ☺
Growth
BOFFFF more biologically valuable

12. Spawning activity is localized in discrete areas

13. Conclusion Spawning activity localised in discrete areas
Synchronised movements between spawning ground and neighboring regions
Major role of the BOFFF in the reproductive capacity

14. Confirm migration pattern (homing pattern)
PROSPECTS
Confirm migration pattern (homing pattern)
Consider the protection of BOFFFF
How to preserve the population age structure
Fishing closure ?
Protected marine areas?
Gear selectivity ?

15. Acknowledgements
This project was an financed by the European Union (FEDER), and the Conseil Régional and Conseil Général de La Réunion.
The authors would like to express their gratitude to the skippers who volunteered to allow scientific observers on board their vessels and to all people involved in the sampling. We thank the fishery industry of Reunion Island for their outstanding support of the “Programme Palangre Réunion” (PPR) project.

16. THANKS FOR YOUR ATTENTION
DO SWORDFISH ♂ PREFER THE BOFFFF ?

17. Spawning occurs in the vicinity of Reunion Island
Histological
analyses
Transverse section of a an early developing ovary stage
Transverse section
of a a ripe ovary in hydratation
Stages 1
Immature 2 3 4 5 6
developing
maturing
ripening
Spawning
Spent or
resting
Maturity scale for females
undeveloped
Ovocyte diameters
Distribution