Remote sensing of invasive tubeworm reefs in the Coorong and Lower Lakes of South Australia

Invasive polycheate tubeworms of the reef-building species Ficopomatus enigmatus have taken advantage of reduced water levels and increasing salinities since 2007 to become established in the Lower Murray Lakes of the South Australia. Methods to remotely detect and map reef formations using digital aerial imagery in a contextual approach utilizing both image analysis and GIS processing with bathymetric data were explored and yielded a high level of accuracy for area estimation. Green band (495-570 nm) image data yielded optimal edge detection for the reef structures. While reefs continue to expand in number and size in the newly established areas of Lake Alexandrina, they appear to be declining in their historical habitats in the Coorong as conditions have become more marine. As tubeworm reefs continue to grow over very large areas and expand their range, the methods explored in this study will prove invaluable for management efforts in the future.