Observations of localised movements and residence times of wobbegong sharks (Orectolobus halei) at Fish Rock, NSW, Australia
Huveneers, C., Harcourt, R. and Otway, N., 2006. Observations of localised movements and residence times of wobbegong sharks (Orectolobus halei) at Fish Rock, NSW, Australia. Cybium, 30(4) Supplement: 103–111.
Acoustic telemetry was used to assess the localised movements of seven wobbegong sharks (Orectolobus halei) for approx. two years at Fish Rock off South West Rocks in northern NSW. Four of the seven sharks were detected for less than 40 days. This was most likely due to tag loss, but these same individuals may have emigrated. Despite this, three sharks were regularly detected for periods of approximately 4, 10 and 20 months suggesting longer-term residency. The wobbegongs were mostly detected by one or two acoustic listening stations located on the southern side of Fish Rock. Diel patterns of behaviour were observed as the sharks had a greater presence during daylight hours than at night. Although excursions occurred about every 3 days, the wobbegongs were found within a small area for periods as long as two years. This sedentary behaviour is likely to decrease wobbegong resilience to fishing effort if intensive fishing occurs within these locations. Moreover, this study showed that some wobbegongs remained within a specific site with small excursions lasting approx. 1.8 days. The long-term residency pattern displayed by three of the sharks suggests that temporal closures or marine protected areas may be effective tools for the management and conservation of local populations. Overall, this initial study indicates that future acoustic telemetry research should provide substantial information on the localised and migratory movements of wobbegongs off the NSW coast.