Obtaining accurate estimates of catch can be challenging for small-scale recreational fisheries. Using inner Shark Bay as a case-study, we investigated whether a state-wide phone-diary (PD) survey could provide robust estimates of boat-based fishing effort and catch (kept and total) of pink snapper (Chrysophrys auratus) and grass emperor (Lethrinus laticaudis). Estimates were compared with those from concurrent surveys for two spatial scales corresponding to the fishery and the three pink snapper stocks within the fishery. A supplementary access point (SAP) survey incorporated remote camera data and interviews with fishers at boat ramps. An aerial survey was used to adjust the SAP estimates, accounting for catches from boat fishers launching from remote beaches (SAP_Aerial). The SAP survey provided the most precise estimates but underestimated catches for one of the stocks. Estimated fishing effort from the SAP_Aerial survey was comparable to the PD survey (3% lower) for inner Shark Bay, as was the estimated kept catch of pink snapper (7% lower) and these estimates were considered robust (Relative Standard Error < 40% and sample size ≥ 30). In contrast, estimates of the total catch of pink snapper and the catch (kept and total) of grass emperor from the PD survey were consistently lower. While the on-site surveys generally provided robust estimates of catch for each stock, most PD estimates were not robust at this scale. The SAP_Aerial survey is considered to be the most appropriate for ongoing monitoring because it provides robust estimates for the spatial scales examined. However, estimates of catch from periodic PD surveys for the entire fishery could be adjusted using the on-site data to provide the stock-specific information required for ongoing assessments of sustainability. Our study demonstrates that corroborative studies assist in monitoring recreational fisheries.

中文翻译：

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证实渔获量估计，为世界遗产地中小型海洋休闲渔业的监测提供信息

对于小型休闲渔业而言，获得准确的渔获量估计可能具有挑战性。以鲨鱼湾内区为案例研究，我们调查了一项全州范围的电话日记 (PD) 调查是否可以提供基于船只的捕捞努力和粉红鲷鱼 (Chrysophrys auratus) 和草的捕捞量（保留和总数量）的可靠估计皇帝（Lethrinus laticaudis）。将估计值与对应于渔业的两个空间尺度和渔业内的三种粉红鲷种群的同时调查的估计值进行了比较。一项补充接入点 (SAP) 调查结合了远程摄像机数据和在船坡道对渔民的采访。航空调查被用来调整 SAP 的估计，考虑到从偏远海滩（SAP_Aerial）发射的渔民的渔获量。SAP 调查提供了最精确的估计，但低估了其中一只种群的渔获量。SAP_Aerial 调查的估计捕鱼量与鲨鱼湾内的 PD 调查（低 3%）相当，粉红鲷鱼的估计保留渔获量（低 7%）也是如此，这些估计被认为是可靠的（相对标准误差 < 40 % 和样本量 ≥ 30)。相比之下，PD 调查对粉红鲷鱼总捕获量和草皇总捕获量（保留和总捕获量）的估计始终较低。虽然现场调查通常对每种种群的渔获量提供了可靠的估计，但大多数 PD 估计在这个规模上并不可靠。SAP_Aerial 调查被认为最适合持续监测，因为它为所检查的空间尺度提供了可靠的估计。然而，可以使用现场数据调整对整个渔业定期 PD 调查的渔获量估计，以提供持续评估可持续性所需的特定种群信息。我们的研究表明，确证研究有助于监测休闲渔业。