An understanding of host–parasite interactions represents an important, but often overlooked, axis for predicting how polar marine biodiversity may be impacted by continued environmental change over the next century. Here, we survey three species of crocodile icefish (Notothenioidei: Channichthyidae) collected from two island archipelagos in the southern Scotia Arc region for evidence of leech infestations. Specifically, we report on infestation prevalence, intensity, spatial patterns of relative abundances, size distribution of parasitized fish, and patterns of host and attachment site specificity. Our results reveal high levels of attachment area fidelity for each leech species. These results suggest skin thickness and density of the vascular network constrain leech attachment sites and further suggest trophic (i.e., post-cyclic) transmission to be an important axis of parasitization. We also demonstrate that, while leech species appear to be clustered spatially, this clustering does not appear to be correlated with fish biomass. This study illuminates the complex interactions among fish hosts and leech parasites in the Southern Ocean and lays the groundwork for future studies of Antarctic marine leech ecology that can aid in forecasting how host–parasite interactions may shift in the face of ongoing climate change.

中文翻译：

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寄生南极鱼水蛭（Piscicolidae）与其鳄鱼冰鱼宿主（Channichthyidae）之间的侵染动态

对宿主-寄生虫相互作用的理解代表了一个重要但经常被忽视的轴，用于预测极地海洋生物多样性如何受到下个世纪持续环境变化的影响。在这里，我们调查了从斯科舍弧南部地区的两个岛屿群岛收集的三种鳄鱼冰鱼（Notothenioidei：Channichthyidae），以寻找水蛭侵扰的证据。具体来说，我们报告了侵染流行率、强度、相对丰度的空间模式、寄生鱼的大小分布以及宿主和附着位点特异性的模式。我们的结果揭示了每种水蛭物种的高水平附着区域保真度。这些结果表明血管网络的皮肤厚度和密度限制了水蛭附着位点，并进一步表明营养性（即，后循环）传播成为重要的寄生轴。我们还证明，虽然水蛭物种似乎在空间上聚集，但这种聚集似乎与鱼类生物量无关。这项研究阐明了南大洋鱼类宿主和水蛭寄生虫之间复杂的相互作用，并为南极海洋水蛭生态学的未来研究奠定了基础，这有助于预测宿主-寄生虫相互作用在面对持续的气候变化时可能如何变化。