Acoustic tracking of Glyphis sp. A in the Adelaide River, Northern Territory, Australia
R. D. Pillans1, J. D. Stevens2, P.M. Kyne3 and J. Salini1
1 CSIRO Marine Research, PO Box 120, Cleveland, Queensland 4163, Australia
2 CSIRO Marine Research, PO Box 1538, Hobart, Tasmania 7001, Australia
3 University of Queensland, School of Biomedical Sciences, Brisbane, Queensland
About this document
In December 2004, 28 Glyphis sp. A were captured in the lower reaches of the Adelaide River, salinity 3.2 - 15 parts per thousand (ppt). The majority of individuals were new recruits of 55-60 cm TL. Three Glyphis sp. A (a 66.5 cm TL male, 165 cm TL female and a 158 cm TL female) were tagged with acoustic tags and tracked for 28.5, 27.0 and 50.2 h, respectively. All sharks showed initial, rapid downstream movements of 4 - 6 h, probably a stress reaction to capture, before settling into a behavioural pattern of cycling up and down-stream with the tidal cycles. Average rate of movement (ROM) for all three sharks varied from 0.45 - 0.52 m.s-1. In the smallest shark ROM did not change between ebb and flood times. However, in the two larger sharks ROM during the ebb tide was significantly faster. There was no difference in ROM and swimming depth between day and night. The movement patterns of these sharks are discussed in relation to the conservation of this species.