Mortality of sand whiting (Sillago ciliata) released by recreational anglers in an Australian estuary

Abstract

Abstract The mortality of hooked-and-released sand whiting (Sillago ciliata) and the key contributing factors were determined during a recreational fishing event in northern New South Wales, Australia. Participating anglers caught 124 sand whiting, of which 60 were tagged with plastic t-bar anchor tags, and then released into replicate sea cages. In all, 109 sand whiting were seined (54 were tagged) and similarly released into replicate sea cages for use as controls. All fish were monitored for mortalities over 7 days. There were no measurable effects of confinement in the sea cages on the stress (measured as concentrations of plasma glucose) of hooked or seined fish. Ten hooked-and-released (four non-tagged, six tagged) and two control (both tagged) sand whiting died during the monitoring period and mostly within 48 h of capture, providing adjusted mortality rates (i.e. accounting for mortalities of control fish) of approximately 6% for total, tagged, and non-tagged fish. Anatomical hook location (oesophagus-ingested hooks) and bait type (beach worms, Australonuphis teres) were significant predictors of mortality (p > 0.05). The results support current recreational fishing gears and practices for the catch and release of sand whiting.