Identification of key drivers of population dynamics and prediction of rates of population recovery following stock decline are crucial aspects of fisheries management. The abundance of a blue swimmer crab population (Portunus armatus) in Cockburn Sound, Western Australia, which once supported the largest commercial fishery for this short-lived species in the State, declined markedly and has remained low despite two commercial fishery closures. This study employed state-space biomass dynamics models to explore evidence for potential factors contributing to the lack of stock recovery, including fishing pressure, changes in primary production (using chlorophyll-a as a proxy) and depensatory stock-recruitment dynamics. Likelihood ratio test results indicated better statistical fits for models with production functions modified to account for chlorophyll-a or both depensation and chlorophyll-a. Models incorporating both depensation and chlorophyll-a provided the most biologically-feasible results (e.g. estimated intrinsic increase, $r$, not near zero) and the estimated biomass trajectories were less uncertain. For all models, estimated annual harvest rates peaked in the late 1990s, prior to the first major stock decline, and again in 2009−12, when the fishery was briefly re-opened with tight management restrictions. Results for models including both depensation and chlorophyll-a indicated that stock productivity is positively-related to chlorophyll-a. Thus, below-average chlorophyll-a concentrations in Cockburn Sound in recent years, in combination with some form(s) of depensation (e.g. associated with predation pressure), may be preventing stock recovery. Despite a sustained period of very limited recreational fishing and no commercial fishing, stock recovery appears highly uncertain under current environmental conditions. The results of this study highlight the value of incorporating environmental data and alternative stock-recruitment assumptions when fitting production models to explore key factors influencing population dynamics.

确定种群动态的关键驱动因素和预测种群下降后种群恢复率是渔业管理的重要方面。西澳大利亚科伯恩湾的蓝鲎种群 ( Portunus armatus ) 曾为该州最大的这种短寿命物种提供商业渔业，但数量显着下降，尽管有两次商业渔业关闭，但数量仍然很低。本研究采用状态空间生物动力学模型，探讨促进缺乏股票恢复，包括捕捞压力，在初级生产变化的潜在因素的证据（使用叶绿素一作为代理）和依赖股票招聘动态。似然比检验结果表明，对生产函数进行修改以考虑叶绿素a或同时考虑叶绿素a和叶绿素a 的模型具有更好的统计拟合。模型并入二者depensation和受叶绿素一个提供的最生物可行的结果（例如估计的固有增加，$r$，不接近于零）并且估计的生物量轨迹不太不确定。对于所有模型，估计年捕捞率在 1990 年代后期达到峰值，在第一次大规模种群下降之前，并在 2009-12 年再次达到峰值，当时渔业在严格的管理限制下短暂重新开放。结果模型既包括depensation和受叶绿素一表示，股票的生产率是受叶绿素正相关的一个。因此，低于平均叶绿素一个近年来科伯恩湾的浓度与某些形式的退化（例如与捕食压力相关）相结合，可能会阻止种群恢复。尽管休闲捕鱼和商业捕鱼的持续时间非常有限，但在当前环境条件下，种群恢复似乎非常不确定。这项研究的结果强调了在拟合生产模型以探索影响人口动态的关键因素时结合环境数据和替代库存招聘假设的价值。