Montara Well Release: Report on necropsies from birds collected in the Timor Sea

Abstract

• Necropsies were collected from 16 birds (13 common noddy, 1 lesser frigatebird, 1 wedge-tailed shearwater, 1 brown booby) collected in the Timor Sea during and following the Montara well release. • A total of 72 samples (38 samples of lungs, breast tissue or gizzard contents, 32 swab samples from feathers and trachea, 2 bile samples) were analysed for the presence of total petroleum hydrocarbons (TPH - gas chromatography with flame ionisation detection) and polycyclic aromatic hydrocarbons (PAH – gas chromatography-mass spectrometry). • Expert examination of the chromatographic pattern produced in the TPH analysis allowed the qualitative assessment of whether the source of the compounds was petroleum hydrocarbons and/ or biological co-extractives (e.g., fatty acids, cholesterol).• One common noddy (collected deceased) from the vicinity of the Montara incident had crude oil on its feathers, in its gizzard contents, in its lungs and in its breast tissue indicating significant exposure to crude oil. Since this bird was very decomposed upon receipt (thoracic cavity open and intestine missing) such exposure could have been pre- and/ or post-mortem. • One common noddy collected at Ashmore Reef had crude oil in its lungs but in no other samples (feather swab, trachea swab, breast tissue, gizzard). The fact that external swabs and intestinal tract samples were negative for the presence of crude oil suggests non-recent exposure. • The remaining 14 birds submitted for analysis had no signs of crude oil in the feathers, in the gizzard contents, in the lungs or in the breast tissues. • The majority of birds submitted for analysis appeared in poor physical condition and are likely to have died of natural causes.