Climate and Environment, NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries, Nygårdsgaten 112, 5008 Bergen, Norway.
Norwegian Institute for Nature Research, Høgskoleringen 9, 7034 Trondheim, Norway.
Proc Biol Sci. 2023 Jan 25;290(1991):20221752. doi: 10.1098/rspb.2022.1752.
Parasite spillback from domestic animals can distort the balance between host and parasites in surrounding wildlife, with potential detrimental effects on wild populations. In aquatic environments, parasite spillback from aquaculture to wild salmon is one of the most contentious sustainability debates. In a 19 year time series of release group studies of Atlantic salmon, we demonstrated that (i) the effect of subjecting out-migrating salmon smolts to parasite treatment on marine survival has been reduced over a time, (ii) the relation between salmon lice levels in the out-migration route of the salmon and effect of treatment against the parasite is weak, but also (iii) the return rates in both treated and untreated groups of salmon are negatively correlated with salmon lice levels, and (iv) returns of wild salmon to the region are similarly negatively correlated with salmon lice levels during the out-migration year. Our study suggests that salmon lice can have a large effect on wild salmon populations that is not revealed with randomized control trials using antiparasitic drugs. This should be better accounted for when considering the impacts of farms on wild salmon populations.
寄生虫从家畜反向传播会破坏周围野生动物中原有的宿主与寄生虫之间的平衡，可能对野生动物种群造成潜在的有害影响。在水生环境中，水产养殖中的寄生虫反向传播到野生三文鱼是最具争议的可持续性辩论之一。在对大西洋三文鱼进行的为期 19 年的洄游群体研究系列中，我们证明了：（i）使洄游的三文鱼幼鱼接受寄生虫处理对海洋生存的影响随着时间的推移而降低；（ii）三文鱼洄游路线中三文鱼虱的水平与针对寄生虫的处理效果之间的关系较弱，但三文鱼虱水平与处理组和未处理组三文鱼的洄游率呈负相关；（iii）三文鱼虱水平与洄游年份野生三文鱼的洄游率呈负相关。我们的研究表明，三文鱼虱对野生三文鱼种群可能产生重大影响，而使用抗寄生虫药物进行的随机对照试验并未揭示这一点。在考虑养殖场对野生三文鱼种群的影响时，应该更好地考虑这一因素。
