Comparing estimates of catch and effort for boat-based recreational fishing from aperiodic access-point surveys

Recreational fishing harvest fluctuates over time according to changes in fish abundance, fisher behaviour, fishery socio-economics and management regulations. Time series of catch and effort are often unavailable, even where harvests from the recreational sector are significant. When surveys are conducted infrequently, inferences between estimates of catch and effort over time may be uncertain, leading to limited understanding of fishery trends and responses to management changes. This study makes statistical comparisons of catch and effort from four access-point surveys between 1996/97 and 2009/10 for a boat-based recreational fishery in south-western Australia. Retained catches of demersal fish were significantly lower in 1996/97 (90,000 fish 4000 se) than 2005/06 (123,000 +/- 4000), and subsequently declined in 2008/09 (95,000 +/- 3500) and 2009/10 (57,000 +/- 2000). In contrast, released catches increased substantially from 1996/97 (30,000 +/- 2000) to 2009/10 (94,000 +/- 4000). While fluctuations in retained catch corresponded with ocean-line fishing effort, sustained increases in released catch followed reduced bag limits and increased size limits and recruitment of juvenile fish for some species. This study highlights the need to monitor recreational fisheries at appropriate intervals, particularly when the impacts of management changes on fish populations need to be considered.