Parasitic copepods Caligus lacustris (Copepoda: Caligidae) on the rainbow trout Oncorhynchus mykiss in cage aquaculture: morphology, population demography, and first insights into phylogenetic relationships

Abstract

Introduction Data on rainbow trout infection with the copepod Caligus lacustris in cage aquaculture on Lake Ladoga is presented. Materials and MethodsCaligus lacustris (n=127 ex.) were collected from a farm in Lake Ladoga housing cage-reared rainbow trout to describe the size-age and sex structure of the copepod population. Morphological features of the copepods were evaluated according to 10 characters with terminology proposed by Kabata, Gusev (1966). To determinate the phylogenetic position of C. lacustris within the genus Caligus, fragments of the cytochrome c oxidase subunit 1 mitochondrial gene (COI, 645 bp) and 18S rRNA gene (1617 bp) were sequenced. ResultsAn increase of parasite prevalence was observed as the lake was warming up from July to September. The morphological features of the crustacean's larval and adult stages, characterized by specific parameters of quantitative traits, are described.Three COI haplotypes and only one 18S rRNA haplotype of C. lacustris were identified among five samples. Based on 18S rRNA analysis (resolution of the COI tree was poor) we can conclude that the clade containing C. lacustris, and the aforementioned sister species, appears as an early radiation of the genus Caligus. ConclusionsThe development of freshwater aquaculture contributes to the transfer of the native parasite Caligus lacustris to farmed rainbow trout.

Science school in ecological parasitology in Karelia

“…по мужской линии [Ziętara et al, 2006]. Сегодняшние исследования лаборатории паразитологии направлены на выяснение селективной роли садковой аквакультуры в формообразовании паразитов, их видовой специфичности и вирулентности для диких лососевых рыб [Ieshko et al, 2016;Parshukov et al, 2021;. Начаты работы по генотипированию форелевых хозяйств и созданию баз данных генетического статуса опасных паразитов разводимых рыб с целью усиления контроля со стороны ветеринарных служб в сфере карантинных мероприятий при перевозке посадочного материала.…”

Evolutionary Rates, Divergence Rates, and Performance of Individual Mitochondrial Genes Based on Phylogenetic Analysis of Copepoda

“…The number of sequenced mitogenomes of Copepoda has greatly increased in recent years, but most previously published molecular phylogenetic studies were based on single loci (mostly 18S, 28S, and cox1 genes) [18,[23][24][25]. There is evidence that, due to the low level of polymorphism, the mitochondrial cox1 gene is not suitable for inferring phylogeny in many metazoan lineages, including copepods [26,27].…”