Presentation is loading. Please wait.

Presentation is loading. Please wait.

Future perspectives: critical habitat and fisheries interactions Movements, diving behaviour and Lévy patterns of satellite tracked blue sharks NUNO QUEIROZ.

Similar presentations


Presentation on theme: "Future perspectives: critical habitat and fisheries interactions Movements, diving behaviour and Lévy patterns of satellite tracked blue sharks NUNO QUEIROZ."— Presentation transcript:

1 Future perspectives: critical habitat and fisheries interactions Movements, diving behaviour and Lévy patterns of satellite tracked blue sharks NUNO QUEIROZ | CIBIO – UNIVERSIDADE DO PORTO

2 Overall objectives  Describe the horizontal movements of tracked blue sharks;  Identify and characterize areas of prolonged residence;  Describe the diving behaviour and habitats occupied by blue sharks;  Test the Lévy-flight foraging hypothesis.

3 Tagging methodology

4 Horizontal movements and spatial aggregations  Broad-scale southern movements moving across different habitat: shelf, shelf-edge and deep water;  Long-term residence in restricted areas.

5 Horizontal movements and spatial aggregations  Aggregation areas coincide with frontal regions;  Regions characterized by high primary productivity and forage accumulation.

6 MEPS 2010 406: 265 - 270 Shifts in diving behaviour  Analysis detected shifts from inshore to offshore locations in all sharks, enabling coastal behaviour to be distinguished from offshore behaviour.

7 Offshore behavioural shifts  Blue shark behaviour was linked to thermal structure of the water column; in well-mixed waters behaviour was irregular, whereas in stratified waters behaviour was regular. MEPS 2010 406: 265 - 270

8 Offshore behavioural shifts  In stratified water, behavioural shifts were likely related to changes in prey type or distribution, suggesting prey-specific search strategies may be involved. MEPS 2010 406: 265 - 270

9 Offshore behavioural shifts  Blue shark behaviour more variable than previously thought;  Sharks of different age groups and at different geographical areas display similar diving patterns: Suggests diving patterns are closely linked to foraging behaviour. MEPS 2010 406: 265 - 270

10 Lévy-flight foraging hypothesis Brownian motion Lévy-flight  Lévy-flight should be performed where prey is sparse and distributed unpredictably;  Brownian movement efficient for locating abundant prey. NATURE 2010 465: 1066 - 1069

11 Lévy-flight foraging hypothesis LBBLL NATURE 2010 465: 1066 - 1069

12 Lévy-flight foraging hypothesis  Enabled preliminary field test of the Lévy-flight foraging hypothesis, with empirical results supporting theoretical predictions.  Diving patterns linked with foraging behaviour (support for foraging hypothesis);  Behavioural switches suggest marine predators adjust optimal foraging patterns to different prey field densities. CONCLUSION NATURE 2010 465: 1066 - 1069

13 Future perspectives: critical habitat and fisheries interactions

14  Satellite track blue and mako sharks in coastal and open ocean areas;  Use long-term movement and behavioural data (e.g. thermal preferences) from real sharks to create model sharks.

15 Future perspectives: critical habitat and fisheries interactions  Vessel monitoring system (VMS) data from Portuguese and Spanish longliners.

16 Future perspectives: critical habitat and fisheries interactions  Determine to what extent future management scenarios influence shark-boat interactions;  How are closures of defined areas likely to increase or decrease interactions?  Provide a valuable insight into how the conservation of oceanic pelagic sharks can be approached. CONCLUSION

17 Acknowledgments  I would like to thank Professor D.W. Sims, A.M. Santos, N.E. Humphries, L.R. Noble, G.R. Mucientes and L.L. Sousa and all the co-authors of the presented works;  CIBIO (Centro de Investigação em Biodiversidade e Recursos Genéticos) and the MBA (Marine Biological Association of the U. K.);  This work was supported by FCT (Fundação para a Ciência e a Tecnologia) and the Save our Seas Foundation.

18 Lévy-flight foraging hypothesis LB NATURE 2010 465: 1066 - 1069


Download ppt "Future perspectives: critical habitat and fisheries interactions Movements, diving behaviour and Lévy patterns of satellite tracked blue sharks NUNO QUEIROZ."

Similar presentations


Ads by Google