Tropical tunas and billfishes (TTBF) are important commercial and game-fishing target species in Australia, with obligations to account for recreational catches in fisheries management and international reporting. However, data collection from the recreational TTBF sector has historically been fragmented and uncertain, limiting its utility for assessing the sector. This gap is particularly important for species like Black and Blue Marlin for which recreational fisheries may provide the primary source of fisheries-dependent information. While a range of programs have collected from the recreational sector for decades, available TTBF data has not previously been evaluated systematically under a common analytical framework.
We assembled and quality-controlled catch, effort, size and participation data for eleven tuna and billfish species from recreational and charter fisheries across eastern Australia and New Zealand including tagging programs, fishing tournaments, game-fishing club records, state recreational fishing surveys and charter logbooks. These datasets differ substantially in temporal coverage, sampling units, reporting completeness, effort information and representation of unsuccessful (zero-catch) trips, so we developed a reproducible workflow for source-specific quality control and mixed-model standardisation. Where supported, we generated annual indicators of catch rate, catch success, catch disposition, fish size and participation to enable a review of the utility of existing TTBF data.
Our assessment found that precision and consistency available vary markedly across region and sparse records limiting inference for rarer species. Several programs contain long-term data that support useful, standardised fishery indicators (e.g. Striped Marlin CPUE), but no individual source provides a comprehensive measure of sector-wide catch or effort. We identify key monitoring gaps across the recreational fisheries’ club, charter, and non-club sectors, including estimation of total catch, and provide recommendations to improve and future-proof TTBF monitoring through coordinated use of existing data streams and targeted, purpose-designed surveys.