Snapper Pagrus auratus (Sparidae) home range dynamics: acoustic tagging studies in a marine reserve

The home-range size and location of reef-associated snapper Pagrus auratus: Sparidae were investigated by use of a radio acoustic-positioning telemetry (RAPT) system. Tags were surgically implanted in 5 snapper that were subsequently monitored every minute for a period of 5 mo, and then intermittently over another 7 mo. Site fidelity was high amongst these fish, with home ranges not exceeding 650 m in diameter or 139600 m2 in area. Eleven other snapper received tags by feeding and were tracked for periods of up to 2.5 d. Site fidelity was also high for these fish, with standardised estimates of home-range size not differing between the 2 groups. Home ranges overlapped considerably, indicating that the fish were not territorial. The location of the home ranges generally remained stable throughout the entire tracking period, although 1 fish relocated its home range by ~220 m. A new method of home-range estimation was developed, which matched the level of detail provided by the RAPT system, to directly estimate the time spent in an area. The relevance of this method and the residential behaviour of these fish are discussed, with reference to the general understanding of animal behaviour, previous investigations into snapper movement, and the selective capacity that may be imposed by marine reserves on fish behaviour.