MEPS 366:219-229 (2008)  -  DOI: https://doi.org/10.3354/meps07519

ABSTRACT: Acoustic telemetry was used to document patterns of movement by black bream Acanthopagrus butcheri (Munro, 1949) throughout Australia’s largest estuary, the Gippsland Lakes. Forty-four fish were surgically implanted with acoustic transmitters and monitored over 12 mo (November 2005 to October 2006). Fish moved throughout the Gippsland Lakes at average rates of 8.7 km d^–1 over 12 mo, with some fish moving distances of up to 2600 km. Fish frequently moved among the major estuarine rivers (Tambo, Mitchell and Nicholson rivers), sometimes moving up to 30 km in a day. Fish use of the rivers, river entrances and lakes varied strongly with the time of year. Fish spent more time in the lakes than rivers in late summer and early autumn, but began to use the rivers more than the lakes at the end of autumn. River use was greatest in early to mid-winter, then gradually decreased through spring. Fish also spent more time in some rivers than others, with use of their respective entrances peaking during transition phases when fish were moving from the rivers to the lakes and vice versa. Time of day was a weak predictor of regional patterns of fish use, but during the transitional phases (March through May) fish use of lakes was greater at night, while use of rivers was greater during the day. Monthly variation in time spent by fish in particular rivers varied positively with the discharge of freshwater (with a concomitant negative relationship between lake use and overall river discharge).

KEY WORDS: Acanthopagrus butcheri · Sparidae · Spatial behaviour · Acoustic telemetry · Gippsland Lakes