Rintamäki-Kinnunen P, Valtonen E T
Department of Biology, University of Oulu, Finland.
Int J Parasitol. 1996 Jul;26(7):723-32. doi: 10.1016/0020-7519(96)00046-x.
The occurrence of Gyrodactylus salaris on Baltic salmon (Salmo salar), sea trout (S. trutta m. trutta) and brown trout (S. trutta m. lacustris) was examined from 1984 to 1993 at 4 fish farms (A, B, C and D) that produce smolts for stocking in northern Finland. No G. salaris was found on the sea or brown trout, but it did occur on salmon for 6-7 years at farms B, C and D, the prevalences of infection being 9.5%, 17.7% and 8.8% for salmon yearlings and smolts during that time, respectively, but less than 1.2% for fingerlings at farms B and C. Only brood stock salmon were infected at farm A in 4 years. The abundances of G. salaris increased during the second winter of each year class and were highest in the spring before stocking. The combination of variables farm, water temperature, age of fish and other ectoparasites did not suffice to explain the occurrence of G. salaris when studied by step-wise logistic regression analysis. It is suggested that other irregular factors at the farm, such as a change in the water intake system, transfers of fish to the farm and the keeping of wild fish at the farm are also important. The present extensive data strongly support previous suggestions that the Baltic salmon is more resistant to G. salaris than salmon migrating into the Atlantic Ocean.
1984年至1993年期间，对芬兰北部4家为放流培育鱼苗的养鱼场（A、B、C和D）的波罗的海鲑鱼（Salmo salar）、海鳟（S. trutta m. trutta）和褐鳟（S. trutta m. lacustris）上的鲑三代虫（Gyrodactylus salaris）的出现情况进行了调查。在海鳟和褐鳟上未发现鲑三代虫，但在B、C和D养殖场的鲑鱼上出现了6至7年，在此期间，一岁鲑鱼和鱼苗的感染率分别为9.5%、17.7%和8.8%，但B和C养殖场的仔鱼感染率低于1.2%。在4年中，只有A养殖场的亲鱼鲑鱼受到感染。每年鲑三代虫的丰度在各年龄组的第二个冬季增加，并在放流前的春季达到最高。通过逐步逻辑回归分析研究时，养殖场、水温、鱼的年龄和其他体外寄生虫等变量的组合不足以解释鲑三代虫的出现情况。建议养殖场的其他不规则因素，如进水系统的变化、鱼转入养殖场以及在养殖场饲养野生鱼等也很重要。目前广泛的数据有力地支持了先前的观点，即波罗的海鲑鱼比洄游到大西洋的鲑鱼对鲑三代虫更具抵抗力。
