Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan.
Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan.
Zoolog Sci. 2020 Dec;37(6):544-553. doi: 10.2108/zs190147.
In Hiroshima Bay, parasitic isopods of the genus infest the black sea bream (Bleeker, 1854) and the Japanese halfbeak (Temminck and Schlegel, 1846), two fish species that are abundant and commercially important in the Seto Inland Sea of Japan. Immature and mature individuals can infect both juveniles and adults of , while immature are known to parasitize juveniles of ; i.e., no parasites are found in adult The identification of the immature parasitizing juveniles of remains uncertain, because species are morphologically identifiable only based on adult females. Also, the biological/ecological relationship between the hosts and parasites has not been studied. Here, we identified the parasites on as Bruce, 1986 by molecular sequence analyses along with other parasites obtained from , the latter being morphologically confirmed by comparison with paratype materials of as well as the similar congener Bruce, 1986. The growth rates of the infected juveniles from June to September in the years 2013-2015 and 2018 were significantly lower than those of the uninfected ones, suggesting a negative effect of the infection on the hosts. Our data on the prevalence and duration of the infection, as well as the body size gain of the hosts and parasites, corroborate a hypothesis that would utilize as an optional intermediate host before it reaches the final host, .
在广岛湾，寄生等足目动物 infest 黑鲷 (Bleeker, 1854) 和日本半颚鱼 (Temminck 和 Schlegel, 1846)，这两种鱼类在日本濑户内海丰富且具有商业重要性。未成熟和成熟的个体可以感染 和 的幼鱼和成鱼，而已知未成熟的 寄生在 的幼鱼中；即，在成年的 中没有 寄生虫。寄生在 的未成熟个体的鉴定仍然不确定，因为 种只能基于成年雌性的形态进行识别。此外，宿主和寄生虫之间的生物/生态关系尚未得到研究。在这里，我们通过分子序列分析以及从 获得的其他寄生虫来鉴定 上的寄生虫为 Bruce, 1986，后者通过与作为模式标本材料的 以及相似的同属 Bruce, 1986 的比较，从形态上得到确认。2013 年至 2015 年和 2018 年 6 月至 9 月感染 幼鱼的增长率明显低于未感染的幼鱼，表明感染对宿主有负面影响。我们关于感染的流行率和持续时间以及宿主和寄生虫的体型增长的数据证实了一种假设，即 会在到达最终宿主 之前将 用作可选的中间宿主。
