Office of Fish and Wildlife Health and Forensics, New Jersey Division of Fish and Wildlife, Oxford, NJ, USA.
Parasitol Res. 2021 Nov;120(11):3709-3723. doi: 10.1007/s00436-021-07329-y. Epub 2021 Oct 2.
Anadromous river herring have declined in many parts of their range, leading to fisheries management efforts to help repopulate this species by improving connectivity of rivers and restoring populations by fish transfers. With data lacking on parasites in these species, this study sought to better understand myxozoans across various life stages and habitats in river herring populations in New Jersey, USA. We compared fish from riverine habitats during early-life growth and adults returning to spawn, marine-phase fish, and landlocked Alewife populations. Three myxozoan species were identified in young-of-the-year (YOY) anadromous river herring, including Kudoa clupeidae in the skeletal musculature, Myxobolus mauriensis in the rib cartilage, and an uncharacterized coelozoic myxozoan within the lumen of mesonephric tubules. In YOY river herring, Blueback Herring were 2 times more likely to be infected by K. clupeidae than Alewife (p = 0.019) and in the Maurice River, fish were 4 times more likely to be infected with M. mauriensis than fish from Great Egg Harbor River (p = 0.000) and 11 times more likely than the Delaware River (p = 0.001). Spawning adult river herring were infected with a previously undescribed myxozoan parasite infecting the kidney. Sequencing the 18S rDNA indicated this species is closely related to Ortholinea species. Myxobolus mauriensis and the Ortholinea-like species were absent from marine-phase river herring indicating that infections were linked to river environments occurring during early-life growth and spawning, respectively. No myxozoans were present in landlocked Alewife, showing that similar infections occurring in rivers were absent in lake environments in the region.
溯河洄游的鲱鱼在其分布的许多地区数量下降，导致渔业管理部门努力通过改善河流的连通性和通过鱼类转移来恢复种群，以帮助该物种重新繁殖。由于这些物种的寄生虫数据缺乏，本研究旨在更好地了解美国新泽西州河流鲱鱼种群中不同生命阶段和栖息地的粘孢子虫。我们比较了河流栖息地中的幼鱼和成鱼洄游产卵的鱼、海洋阶段的鱼和内陆的 Alewife 种群的鱼。在幼鱼（YOY）溯河洄游的鲱鱼中发现了 3 种粘孢子虫，包括骨骼肌肉中的 Kudoa clupeidae、肋软骨中的 Myxobolus mauriensis 和内腔中未描述的腔肠粘孢子虫mesonephric 小管。在 YOY 河鲱鱼中，蓝背鲱鱼感染 K. clupeidae 的可能性是 Alewife 的 2 倍（p=0.019），在 Maurice 河中，鱼感染 M. mauriensis 的可能性是 Great Egg Harbor 河的 4 倍（p=0.000）和 Delaware 河的 11 倍（p=0.001）。洄游产卵的成年河鲱鱼感染了一种以前未描述的粘孢子虫寄生虫，感染肾脏。测序 18S rDNA 表明，该物种与 Ortholinea 物种密切相关。海洋阶段的河鲱鱼中没有 M. mauriensis 和 Ortholinea 样物种，表明感染与幼鱼生长和产卵期间分别发生的河流环境有关。内陆的 Alewife 没有粘孢子虫，表明该地区河流中发生的类似感染在湖泊环境中不存在。
