Depth and space use of leopard coralgrouper Plectropomus leopardus using passive acoustic tracking

Understanding fish movements can help define the seasonal importance of different habitats and isolate spatial and temporal vulnerability to exploitation. Leopard coralgrouper Plectropomus leopardus is one of the main targeted fishery species in the Great Barrier Reef; however, there is no information on long-term movement patterns based on continuous and frequent data points. The objective of this study was to determine long-term space use of P. leopardus and identify any seasonal variation in movement trends. A total of 124 P. leopardus were implanted with V13P acoustic transmitters between 2010 and 2012 and passively tracked. Forty-five VR2W receivers were deployed at 2 reefs to track the movements of tagged individuals. The influence of time of day, season, tagging year, location, and water temperature on several movement measures was investigated. Of the 124 fish tagged, 74 individuals had sufficient detections to be included in analysis of horizontal movement, and 55 were used to analyse vertical movements. Results showed increased horizontal movements and higher activity in deeper water during the day in the austral summer. Movement patterns, both vertically and horizontally, appeared to be influenced by water temperature, but also corresponded with spawning season. Despite increased movements during summer, individuals typically remained in a small area similar to 0.5 km(2) throughout detection periods, indicating that long-range spawning-related movements are rare and that adequate resources are obtained within a small section of habitat year-round. This study provides long-term (similar to 3 yr) movement data for an economically significant reef fish and increases knowledge of spatial and temporal space use patterns.