Investigating the Pathways of Marine Debris Found in the Arafura and Timor Seas

David Griffin, CAWCR

Ilse Kiessling, DEWHA

29 July 2008

Pathways of Marine Debris

Marine debris – not easy to clean up

Pathways of Marine Debris

Many thousands of tonnes of nets

Pathways of Marine Debris

not just ugly

Pathways of Marine Debris

Pathways of Marine Debris

high concentrations: northern Gulf of Carpentaria

Pathways of Marine Debris

White (2004) hypothesis

Pathways of Marine Debris

Bluelink Reanalysis: 0-10m, daily velocity average,release items for 1 year, follow them for another year

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Add wind*3% to 0-10m, daily average current

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Feb0-10m

Pathways of Marine Debris

May0-10m

Pathways of Marine Debris

Aug0-10m

Pathways of Marine Debris

Nov0-10m

Pathways of Marine Debris

Pathways of Marine Debris

Pathways of Marine Debris

Conclusions

• Do nets move at the 0-10m velocity?• If so, the model suggests they must come from the Pacific.• But few nets are found on the Great Barrier Reef• probable explanation:• the model has too much flow through Torres

Pathways of Marine Debris

Recommended future work

• include effect of tides on bottom drag• determine drift characteristics of derelict nets• validate model by releasing drifters in Arafura Sea

Thank you

Email: David.Griffin@csiro.au Web: www.cmar.csiro.au