Boussellaa Wiem, Neifar Lassad, Goedknegt M Anouk, Thieltges David W
Department of Life Sciences, Faculty of Sciences of Sfax, Sfax University, Sfax, Tunisia.
Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, Den Burg Texel, Netherlands.
PeerJ. 2018 Sep 14;6:e5558. doi: 10.7717/peerj.5558. eCollection 2018.
Parasites can play various roles in the invasion of non-native species, but these are still understudied in marine ecosystems. This also applies to invasions from the Red Sea to the Mediterranean Sea via the Suez Canal, the so-called Lessepsian migration. In this study, we investigated the role of parasites in the invasion of the Lessepsian migrant in the Tunisian Mediterranean Sea.
We compared metazoan parasite richness, prevalence and intensity of (Perciformes: Sphyraenidae) with infections in its native congener by sampling these fish species at seven locations along the Tunisian coast. Additionally, we reviewed the literature to identify native and invasive parasite species recorded in these two hosts.
Our results suggest the loss of at least two parasite species of the invasive fish. At the same time, the Lessepsian migrant has co-introduced three parasite species during the initial migration to the Mediterranean Sea, that are assumed to originate from the Red Sea of which only one parasite species has been reported during the spread to Tunisian waters. In addition, we found that the invasive fish has acquired six parasite species that are native in the Mediterranean Sea. However, parasite richness, prevalence and intensity were overall much lower in the invasive compared to the native fish host in the Mediterranean Sea.
These results suggest that the Lessepsian migrant may affect native fish hosts by potentially altering the dynamics of native and invasive parasite-host interactions via parasite release, parasite co-introduction and parasite acquisition. They further suggest that the lower infection levels in the invasive fish may result in a competitive advantage over native fish hosts (enemy release hypothesis). This study demonstrates that cross-species comparisons of parasite infection levels are a valuable tool to identify the different roles of parasites in the course of Lessepsian migrations.
寄生虫在非本地物种的入侵过程中可发挥多种作用，但在海洋生态系统中，这些作用仍未得到充分研究。这同样适用于通过苏伊士运河从红海到地中海的入侵，即所谓的莱塞普斯迁移。在本研究中，我们调查了寄生虫在突尼斯地中海海域莱塞普斯迁移物种入侵中的作用。
我们通过在突尼斯海岸的七个地点对这些鱼类物种进行采样，比较了（鲈形目：金梭鱼科）与其本地同属物种感染后生动物寄生虫的丰富度、患病率和感染强度。此外，我们查阅了文献，以确定在这两种宿主中记录的本地和入侵寄生虫物种。
我们的结果表明，入侵鱼类至少丧失了两种寄生虫物种。与此同时，莱塞普斯迁移物种在最初迁移到地中海期间共同引入了三种寄生虫物种，这些物种被认为原产于红海，其中只有一种寄生虫物种在扩散到突尼斯水域期间被报道过。此外，我们发现入侵鱼类获得了六种地中海本地的寄生虫物种。然而，与地中海的本地鱼类宿主相比，入侵鱼类的寄生虫丰富度、患病率和感染强度总体上要低得多。
这些结果表明，莱塞普斯迁移物种可能会通过寄生虫释放、寄生虫共同引入和寄生虫获得，潜在地改变本地和入侵寄生虫 - 宿主相互作用的动态，从而影响本地鱼类宿主。它们进一步表明，入侵鱼类较低的感染水平可能使其相对于本地鱼类宿主具有竞争优势（天敌释放假说）。这项研究表明，寄生虫感染水平的跨物种比较是确定寄生虫在莱塞普斯迁移过程中不同作用的宝贵工具。
