Antarctic toothfish Dissostichus mawsoni and Weddell seals Leptonychotes weddellii are important mesopredators in the waters of the Antarctic continental shelf. They compete with each other for prey, yet the seals also prey upon toothfish. Such intraguild predation means that prevalence and respective demographic rates may be negatively correlated, but quantification is lacking. Following a review of their natural histories, we initiate an approach to address this deficiency by analysing scientific fishing catch per unit effort (CPUE; 1975–2011 plus sporadic effort to 2018) in conjunction with an annual index of seal abundance in McMurdo Sound, Ross Sea. We correlated annual variation in scientific CPUE to seal numbers over a 43 year period (1975–2018), complementing an earlier study in the same locality showing CPUE to be negatively correlated with spatial proximity to abundant seals. The observed relationship (more seals with lower CPUE, while controlling for annual trends in each) indicates the importance of toothfish as a dietary item to Weddell seals and highlights the probable importance of intra- and inter-specific competition as well as intraguild predation in seal-toothfish dynamics. Ultimately, it may be necessary to supplement fishery management with targeted ecosystem monitoring to prevent the fishery from having adverse effects on dependent species.

中文翻译：

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南极牙鱼对威德尔海豹很重要的进一步证据

南极牙鱼鲶鱼和威德尔海豹威德利纤毛虫是南极大陆架水域的重要中食肉动物。它们相互竞争猎物，但海豹也捕食牙鱼。这种内部捕食意味着流行率和各自的人口统计率可能呈负相关，但缺乏量化。在回顾了它们的自然历史之后，我们通过分析每单位努力的科学捕捞量（CPUE；1975-2011 加上到 2018 年的零星努力）以及罗斯麦克默多海峡的海豹丰度年度指数，开始了解决这一缺陷的方法海。我们将科学 CPUE 的年度变化与 43 年期间（1975-2018 年）的海豹数量相关联，补充了同一地点的一项早期研究，该研究表明 CPUE 与大量海豹的空间接近度呈负相关。观察到的关系（更多的海豹具有较低的 CPUE，同时控制了每个海豹的年度趋势）表明牙鱼作为一种饮食项目对威德尔海豹的重要性，并强调了海豹中种内和种间竞争以及公会内捕食的可能重要性- 牙鱼动力学。最终，可能有必要通过有针对性的生态系统监测来补充渔业管理，以防止渔业对依赖物种产生不利影响。