Attempts to model the giant mud crab Scylla serrata fishery in the Northern Territory (Australia), have often been complex and the results difficult to interpret, leading to divergent estimates of fishing mortality. This has hindered the development of meaningful management policy. Additionally, analyses based on the entire Northern Territory fishery have masked the extreme variation in catches observed along the Gulf of Carpentaria coast. We applied a structurally simple model to visualize the historical patterns in stock size, recruitment, fishing mortality, and fishing mortality at maximum sustainable yield in the western Gulf of Carpentaria mud crab fishery (WGOCMCF) from 1983 to 2017. We also projected future catch and female spawning stock biomass (FSSB) under positive, neutral, and negative recruitment scenarios for three closure periods contained in the fishery harvest strategy (which start in October, if triggered) and compared these with the results of equivalent closures beginning in September. This exercise was undertaken because of known and significant changes in the proportion of fishing effort across different months as well as large variations in the proportion of females harvested each month (with both factors being particularly low in December). These differences were annualized and incorporated into the yearly time step of the model. Predicted catch and FSSB were similar for shorter closure periods (3 or 6 weeks), irrespective of the starting month. However, initiating a 3‐month closure in September rather than October could lead to a 16–17% increase in FSSB under negative and average recruitment anomalies, imposing a 9–10% reduction in predicted catch. Based on our experience applying a simple model to the WGOCMCF, we also describe processes and practices that could improve the quality of assessment data for this and other data‐moderate crab fisheries.

中文翻译：

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简单模型可为数据适度的螃蟹渔业提供收获策略政策的信息

尝试对巨型泥蟹Scylla serrata建模北领地（澳大利亚）的渔业往往很复杂，其结果难以解释，导致对渔业死亡率的估计不一。这阻碍了有意义的管理政策的发展。此外，基于整个北领地渔业的分析掩盖了在卡彭塔里亚海湾沿岸观察到的渔获量的极端变化。我们使用结构简单的模型来可视化1983年至2017年西部卡彭塔里亚湾泥蟹捕捞业（WGOCMCF）的种群规模，募集，捕捞死亡率和捕捞死亡率以最大可持续产量的历史模式。我们还预测了未来的捕捞量和阳性，中性，雌性产卵生物量（FSSB）以及渔业捕捞战略中三个封闭期的负面招聘情景（如果触发，将在十月开始），并将其与九月开始的同等封闭的结果进行比较。进行此练习的原因是，不同月份之间的捕捞努力比例发生了已知的重大变化，而且每月收获的女性比例有很大差异（这两个因素在12月特别低）。这些差异被逐年化并纳入模型的年度时间步长。不管开始的月份如何，较短的关闭时间（3或6周）的预测产量和FSSB都相似。但是，在9月而不是10月开始3个月的停业可能导致FSSB在负面和平均招聘异常情况下增加16-17％，导致预计产量减少9-10％。基于我们将简单模型应用于WGOCMCF的经验，我们还描述了可以改善该和其他数据中等蟹类渔业评估数据质量的过程和实践。