Seabird Monitoring

Northwest Shelf, Western Australia

Astron has been undertaking an annual seabird monitoring program on islands off the Northwest Shelf of Western Australia since 2011. The focal species are the Wedge-tailed Shearwater (Ardenna pacifica) and Bridled Terns (Onychoprion anaethetus). However, Silver Gulls (Chroicocephalus novaehollandiae) are also monitored as there is a risk that their abundance may increase and impact other nesting seabirds and turtle hatchlings.

Astron recently reviewed and revised the monitoring program to ensure that objectives related to compliance conditions were being met and that the design and methods were robust. As part of this review, control charts were developed for three key parameters for nesting seabirds: nest/burrow density, breeding participation rate and breeding success rate.

Overall, monitoring results have been within the control limits for key breeding parameters. However, it is apparent that regional changes in the broader population are occurring. Pre-breeding conditions, particularly sea surface temperatures, are known to have an important influence on breeding patterns. For example when the Southern Oscillation Index shifts to El Niño, this reduces the intensity of the southward flowing Leeuwin current along Australia’s west coast which results in cooler waters and a consequent reduction in the production of food resources for nesting seabirds.

Key elements in this monitoring program being effective and informative are Astron’s experienced zoologists and the support of an in-house analytical team. Astron’s analysis and information products, including control charts, allows for potential impacts to be accurately assessed and for the most appropriate management response to be formulated.

Seabird Monitoring
Seabird Monitoring
Seabird Monitoring
Seabird Monitoring  : Image 1
Seabird Monitoring  : Image 2
Seabird Monitoring  : Image 3