Search

Pseudochaenichthys georgianus In the South Georgia icefish, 16 helminth species were recorded (from 3 to 12 species per host), including 3 species of trematodes, 4 species of cestodes, 5 species of nematodes and 4 species of acanthocephalans (table 3). Estimated species richness was 18 (Chao1), 19 (jackknife) or 17 (bootstrap) species. The diversity indices equalled 1.54 (Shannon), 0.68 (Simpson), and 0.55 (Pielou’s evenness). All the cestode species, as well as the nematodes Anisakis sp., Contracaecum sp. and Pseudoterranova sp. and acanthocephalans Corynosoma spp. parasitize P. georgianus on larval stages. Thus, P. georgianus is considered to be a definitive host for 6 out of 16 helminth species recorded. As in the mackerel icefish, cestodes predominated in the helminth community of P. georgianus; together they comprised 78.7 % of the total helminth number (fig. 1). According to the prevalence of infection, 8 species predominated in the helminth community in P. georgianus (table 3). Bilocular and trilocular metacestodes had an infection prevalence higher than 95 %. The cestode Diphyllobothrium sp., the trematodes M. pennelli and N. georgiensis, the nematodes Contracaecum sp. and Pseudoterranova sp. had an infection prevalence of 70–95 %. The nematode D. fraseri and monolocular metacestodes were common, with the infection prevalence of 36.4 % and 45.5 %, correspondingly. Other 8 species of helminth occurred in less than 30 % of examined P. georgianus. In all three latter fish species, the proportion of helminth species found on larval stages was larger (62.5–75 %) than that of the species represented by adult parasites (25–37.5 %) (fig. 2). The helminth species richness appeared to be much higher in fishes from shallowwater (10–30 m deep) habitats than in deep-water (60–800 m) habitats (table 4). Analysis of similarity between helminth faunas in studied samples of shallow- and deepwater fishes (table 5) revealed the highest similarity of helminth faunas in two shallow-water species from the Ukrainian Antarctic Station area: P. charcoti and N. coriiceps (SØrensen index 90.6 %) and C. aceratus with N. coriiceps and P. charcoti (88.0 % and 89.8 %, respectively). Also, helminth faunas of deep-water populations of C. aceratus and P. georgianus were similar (SØrensen index 88.9 %). The lowest similarity was recorded for the helminth fauna of the deep-water population of C. gunnari; the similarity between N. coriiceps and C. gunnari was minimal (20.0 %). Visualization of the helminth faunal similarities according to the Bray-Curtis index using the cluster analysis (fig. 3) showed a clear division of groups of shallow- and deepwater fish species. According to the results of the SIMPER analysis, the overall dissimilarity between the helminth communities of shallow- and deep-water fishes was 80.1 %. Four helminth species had the largest contribution to the dissimilarity: the acanthocephalan Corynosoma pseudohamanni (19.4 % contribution), anisakid nematodes Contracaecum sp. (17.4 % contribution) and Pseudoterranova sp. (14.4 % contribution), and trilocular metacestodes (11.4 % contribution). Infection of shallow-water fishes with C. pseudohamanni and anisakid nematodes was more than 10–15 times higher, while deep-water fishes had 168 times higher infection with trilocular metacestodes., Published as part of Kuzmina, T. A., Salganskiy, O. O., Vishnyakova, K. O., Ivanchikova, J., Lisitsyna, O. I., Korol, E. M. & Kuzmin, Yu. I., 2022, Helminth Diversity In Teleost Fishes From The South Orkney Islands Region, West Antarctica, pp. 135-152 in Zoodiversity 56 (2) on page 142, DOI: 10.15407/zoo2022.02.135, http://zenodo.org/record/7175665

Kuzmina, T. A., Salganskiy, O. O., Vishnyakova, K. O., Ivanchikova, J., Lisitsyna, O. I., Korol, E. M., Kuzmin, Yu. I. (2022): Helminth Diversity In Teleost Fishes From The South Orkney Islands Region, West Antarctica. Zoodiversity 56 (2): 135-152, DOI: 10.15407/zoo2022.02.135, URL: http://dx.doi.org/10.15407/zoo2022.02.135

Chaenocephalus aceratus In the blackfin icefish, 19 helminth species were recorded (from 3 to 13 species per host), including 3 species of trematodes, 4 species of cestodes, 5 species of nematodes and 7 species of acanthocephalans (table 3). Estimated species richness was 20 (Chao1), 24 (jackknife), or 22 (bootstrap) species. The diversity indices equalled 1.88 (Shannon), 0.78 (Simpson), and 0.63 (Pielou’s evenness). All the cestode species, as well as nematodes of the genera Anisakis, Contracaecum and Pseudoterranova and acanthocephalans of the genus Corynosoma parasitized this fish host on the immature stages. Thus, C. aceratus is considered to be a definitive host for 7 out of 19 helminth species recorded. Nematodes predominated in the helminth community of blackfin icefish, they comprised 44.99 % of the total helminth number. The proportion of other groups of helminths was lower: 30.96 % for cestodes, 13.61 % for acanthocephalans, and 10.43 % for trematodes (fig. 1). According to the prevalence, three species predominated in the helminth community in C. aceratus: the cestode Diphyllobothrium sp. (P = 100 %), the trematode N. georgiensis (P = 95.5 %), and the nematode Pseudoterranova sp. (P = 95.5 %) (table 3). Five other helminth species had an infection prevalence higher than 50 % and may be considered as subdominant species: bilocular and trilocular metacestodes, the nematode Contracaecum sp., and the acanthocephalans C. bullosum and C. hamanni. The nematode D. fraseri and the acanthocephalan C. evae were common, with an infection prevalence of 45.5 %. Other 10 species of helminths were found in less than 30 % of examined C. aceratus., Published as part of Kuzmina, T. A., Salganskiy, O. O., Vishnyakova, K. O., Ivanchikova, J., Lisitsyna, O. I., Korol, E. M. & Kuzmin, Yu. I., 2022, Helminth Diversity In Teleost Fishes From The South Orkney Islands Region, West Antarctica, pp. 135-152 in Zoodiversity 56 (2) on page 141, DOI: 10.15407/zoo2022.02.135, http://zenodo.org/record/7175665