Kuzmina_02_2022.indd UDC 595.1:597.5(1-13:411.2:1-15:9) HELMINTH DIVERSITY IN TELEOST FISHES FROM THE SOUTH ORKNEY ISLANDS REGION, WEST ANTARCTICA T. A. Kuzmina1*, O. O. Salganskiy2, K. O. Vishnyakova2,3, J. Ivanchikova1,2,3, O. I. Lisitsyna1, E. M. Korol4, Yu. I. Kuzmin1,5 1Schmalhausen Institute of Zoology, NAS of Ukraine, vul. B. Khmelnytskogo, 15, Kyiv, 01030 Ukraine 2State Institution National Antarctic Scientifi c Center; Taras Shevchenko Blvd, 16, Kyiv, 02000 Ukraine 3Scientifi c Research Institution Ukrainian Scientifi c Centre of Ecology of the Sea, Ministry of Ecology and Natural Resources of Ukraine, 89, Frantsuzsky Blvd, Odesa, 65062, Ukraine 4National Museum of Natural History NAS of Ukraine; 15, Bogdan Khmelnytskyi Street, Kyiv, 01030 Ukraine 5African Amphibian Conservation Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom Campus; Private Bag X6001, Potchefstroom 20520, South Africa *Corresponding author E-mail: taniak@izan.kiev.ua T. A. Kuzmina (https://orcid.org/0000-0002-5054-4757) O.O. Salganskiy (https://orcid.org/0000-0002-7063-1807) K. O. Vishnyakova (https://orcid.org/0000-0002-6455-6601) J. Ivanchikova (https://orcid.org/0000-0001-8194-6989) O. I. Lisitsyna (https://orcid.org/0000-0002-2975-3300) E. M. Korol (https://orcid.org/0000-0002-4061-5179) Yu. I. Kuzmin (https://orcid.org/0000-0002-1723-1265) Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica. Kuzmina, T. A., Salganskiy, O. O., Vishnyakova, K. O., Ivanchikova, J., Olga, O. I., Lisitsyna, O. I., Korol, E. M., Kuzmin, Yu. I. — Helminths of 12 fi sh species collected near the South Orkney Islands, West Antarctica were studied. In the whole sample of 115 fi sh specimens, we identifi ed one species of Monogenea, 5 species of Trematoda, 4 species of Cestoda, 5 species of Nematoda, and 7 species of Acanthocephala. All cestode species, 3 species of nematodes, and 5 species of acanthocephalans were represented only by larval stages; fi sh are defi nitive hosts for the remaining 10 helminth species. Details of composition and structure of helminth communities were studied in 3 fi sh species: Chaenocephalus aceratus (Lönnberg, 1906), Champsocephalus gunnari Lönnberg, 1905, and Pseudochaenichthys georgianus Norman, 1937, each represented by more than 20 specimens in a sample. In these hosts, 19, 8, and 16 helminth species were found, correspondingly. In the helminth communities of C. aceratus and P. georgianus, the highest values of the infection prevalence and abundance were recorded for larval cestodes (Diphyllobothrium sp., Tetrabothriidea), nematodes (Pseudoterranova sp., Contracaecum sp.), acanthocephalans (Corynosoma spp.), as well as adults of the trematode Neolebouria georgiensis Gibson, 1976. Th e same trematode species and larval cestodes predominated in the helminth community of C. gunnari. All recorded species of parasites are generalists, each known from a range of fi sh hosts in Antarctica. K e y w o r d s: Helminths, Acanthocephala, Nematoda, Cestoda, Trematoda, teleost fi shes, Antarctica. Zoodiversity, 56(2):135–152, 2022 DOI 10.15407/zoo2022.02.135 Parasitology 136 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin Introduction Rapid modifi cations caused by climatic changes and anthropogenic infl uence are taking place nowadays in terrestrial and marine ecosystems. Special attention of researchers worldwide is paid to the exploration of the changes in ecosystems, as well as to the study of diff erent groups of organisms as indicators of these changes. Metazoan parasites are considered as one of the most sensitive indicators of the state of marine ecosystems ( Hudson et al., 2006; Poulin, 2006; Poulin and Mouritsen, 2006; Hechinger et al., 2007). Most marine parasites are included in the food chains of their defi nitive, intermediate and paratenic hosts ( Marcogliese, 2002, 2016; Th ompson et al., 2004). Changes in the composition and structure of parasite communities of marine animals were recorded in various regions of the world ( Sala and Knowlton, 2006; Blanar et al., 2009; Byers, 2021; Kuzmina et al., 2020, 2022). Due to the complexity of the functioning of host-parasite systems in marine ecosystems, assessment of the changes in communities of diff erent groups of parasites may reveal general trends in the changes in the ecosystems even faster than it can be observed using geological or oceanographic monitoring data. The structure of polar ecosystems in the Arctic and Antarctic is much more complex and ecologically diverse than it was previously thought ( Chown et al., 2015). Besides, marine ecosystems in Antarctica and the Southern Ocean are highly endemic. Recent surveys suggest that 50 % to 97 % of the Southern Ocean species of such groups as sponges, tube worms, amphipods, molluscs, isopods, sea spiders and notothenioid fish are endemic ( Eastman, 2000, 2005; De Broyer et al., 2014; Chown et al., 2015). Organisms inhabiting the extreme conditions of Antarctic marine ecosystems have developed particular physiological and behavioural mechanisms to adapt to survival, growth, and reproduction. Moreover, the isolation of the Southern Ocean ecosystems by the circular Antarctic Polar Front increases ecological diversification of the Antarctic shelf; therefore, ecosystems of the Antarctic shelf areas can be considered as evolutionary hot spots (Eastman, 2005). Th e fi sh fauna in the Southern Ocean around Antarctica, as known today, consists of 322 species from 50 families (Eastman, 2005); the dominant group of fi shes belongs to the perciform suborder Notothenioidei, which comprises about 77 % of Antarctic fi sh species diversity ( Kock, 2005; Near, 2009; Near et al., 2012). Th e suborder includes more than 130 species in eight families (Artedidraconidae, Bovichtidae, Pseudaphritidae, Eleginopsidae, Nototheniidae, Harpagiferidae, Bathydraconidae, Channichthyidae) which are endemic of Southern Ocean (Near et al., 2012). Th is group includes the species of high economic importance to fi sheries (Gon and Heemstra, 1990; Kock 1992; Collins et al. 2010), as well as the species that represent critical links in the Antarctic food webs, especially for higher-level consumers such as seals, whales, and marine birds ( Targett 1981; Smith et al., 2007; Parker et al., 2020). In recent years, there has been an increase in the interest in the study of Antarctic fi sh parasites ( Oğuz et al., 2012, 2015; Shendrik et al., 2014; Gordeev and Sokolov, 2016; Sokolov et al., 2016, 2019; Münster et al., 2016, 2017; Kuhn et al., 2018; Kvach and Kuzmina, 2020; Kuzmina et al., 2020, 2021a,b, 2022). Th e collection and publication of new data have broadened the understanding of the diversity in parasite fauna of teleost fi sh. However, the lack or insuffi cient baseline data for Antarctic parasite communities do not allow integrating these organisms in any forecasts of the changes in Southern Ocean biodiversity ( Bielecki et al., 2008; Muñoz and Cartes, 2020). In previous decades, the majority of the studies on fi sh parasites has been carried out either on economi- cally important fi sh species such as Dissostichus mawsoni Norman, 1937, D. eleginoides Smitt, 1898, Gobiono- tothen gibberifrons Lönnberg, 1905, etc. ( Parukhin and Lyadov, 1982; Parukhin, 1986; Brickle et al., 2005; Gor- deev and Sokolov, 2016), or on demersal fi shes Notothenia coriiceps Richardson, 1844, Trematomus newnesi Boulenger, 1902, T. bernacchii Boulenger, 1902, etc., which could be easily caught using simple fi shing gear ( Wojciechowska, 1993; Zdzitowiecki, 1979, 1983, 1987, 1996; Zdzitowiecki and White, 1996; Zdzitowiecki and Laskowski, 2004; Laskowski and Zdzitowiecki, 2005; Laskowski et al., 2007; Kuzmina et al., 2020, 2021 a, 2022). Very few publications were devoted to the study of parasites of pelagic fi sh species in deep-sea areas (Palm, 2007; Münster et al., 2017; Kuhn et al., 2018; Sokolov et al., 2016, 2019; Muñoz and Cartes, 2020). On the other hand, the wide distribution and long-distance migrations of pelagic fi sh might enable collecting the informa- tion on the role of teleost fi shes in the life cycles of diff erent groups of metazoan parasites as well as their role in the food webs of marine mammals and birds of Antarctica. In the present study, we examined the helminth diversity in 12 species of teleost fi shes from three families of the suborder Notothenioidei from the South Orkney Islands region, West Antarctica and analysed the hel- minth community structure in three most abundant fi sh species, namely Champsocephalus gunnari Lönnberg, 1905, Pseudochaenichthys georgianus Norman, 1937, and Chaenocephalus aceratus (Lönnberg, 1906). Com- parative analysis of the parasite communities of shallow-water (10–30 m depth) and deep-water (> 60–800 m) fi sh species was performed to obtain new information on the infl uence of shallow- or deep-water habitats on helminth fauna in Antarctic fi sh. Material and methods Field studies and the material collection were carried out from December 2020 till March 2021 in waters around South Orkney Islands (60°40'54" S; 45°11'09" W) during the research trip on the Ukrainian krill fi shing 137Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica trawler “More Sodruzhestva” (CCAMLR statistical subarea 48.2). Totally, 115 fi sh specimens of 12 species were collected as by-catch from the depth of 60 m to more than 800 m (table 1). All fi shes collected were transported to the laboratory, measured, weighed and examined using the standard parasitological techniques (see Zdzitowiecki and Laskowski, 2004; Weber and Govett, 2009). Th e fi shes were examined on the same day they were caught; all precautions were followed to prevent confusion of the parasites between fi sh specimens. Parasites were collected manually from the fi sh body cavity, stomach, intestine, liver and mesentery; all ectoparasites were carefully gathered from the fi sh body surface and gills; only monogenean helminths were examined and identifi ed in the present study. All helminths were washed in saline and fi xed in 70 % ethanol. Acanthocephalans were kept in tap water for 30 min to 3 hours for proboscis evagination prior to their fi xation in ethanol. Helminths belonging to main taxonomic groups (monogeneans, nematodes, cestodes, trematodes and acanthocephalans) were counted, fi xed and stored separately. Identifi cation of the parasites was performed in the laboratory of the Department of Parasitology, I. I. Schmalhausen Institute of Zoology NAS of Ukraine in Kyiv, Ukraine, using the Zeiss Axio Imager M1 compound microscope equipped with DIC optics and a digital imaging system. Prior to identifi cation, all nematodes, cestodes and trematodes were clarifi ed in lactophenol (25 % lactic acid, 25 % phenol, 25 % glycerin, and 25 % distilled water); acanthocephalans were studied on temporary total mounts in the Berlese medium (Swan, 1936). Identifi cation of nematodes was performed according to Mozgovoy (1951) and Rocka (1999, 2004, 2017); cestodes were identifi ed according to Wojciechowska (1993) and Rocka (2003, 2017); trematodes were identi- fi ed according to Zdzitowiecki (1996), Zdzitowiecki and Cielecka (1997 a, b), Gibson et al. (2002), and Jones et al. (2005). Identifi cation of acanthocephalans was performed according to Zdzitowiecki (1983, 1984 a, b, 1987, 1996) and Laskowski and Zdzitowiecki (2017). Th e helminth specimens were deposited in the Parasitological collection of the Department of Parasitology of the  I.  I.  Schmalhausen Institute of Zoology NAS of Ukraine (Kyiv, Ukraine). Data summaries and descriptive analyses were performed using Microsoft Excel and Paleontological Sta- tistics Soft ware (PAST v. 3.0) ( Hammer et al., 2001). Th e prevalence (P), mean abundance (MA), mean and median intensity (I) of infection were calculated for each helminth species following the defi nitions of Bush et al. (1997). Th e species richness in the helminth communities estimated using Chao1 and bootstrap meth- ods was calculated using the PRIMER 6 soft ware ( Clarke and Gorley, 2006). For comparative analysis of the helminth communities of shell-water (10–30 m depth) and deep-water (60 – > 800 m) fi sh species, previously collected and partially published (see Kuzmina et al., 2021 a) data from the area of the Ukrainian Antarctic Sta- tion “Akademik Vernadsky” in 2019–2021 were used. Information on the helminth communities of three fi sh species: N. coriiceps (n = 78; 15,451 helminth specimens), P. charcoti (n = 18; 5,298 helminth specimens) and C. aceratus (n = 6; 4,830 helminth specimens) was included in the analysis. Th e similarity between helminth faunas in shallow- and deep-water fi shes was analyzed using the Sørensen index, the Bray-Curtis index, and SIMPER (similarity percentage) routine. T a b l e 1. Parameters of the samples and number of helminths collected from 12 species of teleost fi shes in waters around the South Orkney Islands in 2020–2021 Fish species No. Weight, g (min–max) TBL*, cm (min–max) No. of helminths collected Family Channichthyidae Gill, 1861 1. Chaenocephalus aceratus (Lönnberg, 1906) 22 177–1347 336.0–58.0 5,789 2. Champsocephalus gunnari Lönnberg, 1905 34 260–900 37.0–49.0 1,267 3. Pseudochaenichthys georgianus Norman, 1937 33 797–1910 41.0–56.0 7,645 4. Neopagetopsis ionah Nybelin, 1947 6 95–1005 25.0–53.5 90 5. Chionodraco rastrospinosus DeWitt et Hureau, 1979 4 368–580 35.5–40.0 192 6. Chaenodraco wilsoni Regan, 1914 1 120 24.5 11 Family Nototheniidae Günther, 1861 7. Notothenia coriiceps Richardson, 1844 2 1047–1110 39.0–48.0 440 8. N. rossii Richardson, 1844 1 3400 64.0 193 9. Gobionotothen gibberifrons (Lönnberg, 1905) 5 286–675 33.5–39.5 214 10. Nototheniops larseni (Lönnberg, 1905) 1 52.9 19.5 80 Family Bathydraconidae Regan, 1913 11. Parachaenichtys charcoti (Vaillant, 1906) 2 330–350 38.5–40.0 557 12. Gymnodraco acuticeps Boulenger, 1902 4 75–166 24.0–29.5 1,683 * Total body length. 138 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin Results All 12 fi sh specimens examined were found to be infected with helminths; each host individual harboured from 1 to 13 helminth species and from 2 to 955 helminth specimens. In total, 18,159 helminth specimens were collected and assigned to 22 species belonging to fi ve taxonomic groups: Monogenea (1 species), Trematoda (5), Nematoda (5), Cestoda (4), and Acanthocephala (7) (table 2). Trilocular metacestodes (unidentifi ed species of the order Tetrabothriidea) were found in all host species except N. larseni. Larval nematodes Contracaecum sp., as well as bilocular metacestodes and metacestodes of Diphyllobothrium sp. were found each in 10 fi sh host species. More than a half of examined host species were infected with the nematode Pseudoterranova sp. (9 hosts), with acanthocephalan species of the genus Corynosoma, namely C. bullosum (8 hosts), C. hamanni (7 hosts), and C. evae (7 hosts), and the trematode N. georgiensis (8 hosts). Th e acanthocephalan C. shackletoni was found only in C. aceratus, while the monogenean P. nototheniae was found in two species of Notothenia, and the trematode L. garrardi was found in N. larseni and P. charcoti. In the present study, the detailed analysis of the helminth communities was performed for three fi sh species, for which we had samples of more than 20 specimens, namely Chaenocephalus aceratus (n = 22), Champsocephalus gunnari (n = 34), and Pseudochaenichthys georgianus (n = 33). For each of the other fi sh species, we present only the information on helminth species found and the predominant group of parasites. Neopagetopsis ionah Six examined specimens of Jonah’s icefi sh harboured a total of 4 helminth species (from 1 to 4 species per host): larval nematodes Contracaecum sp. were found in three host individuals, metacestodes of Diphyllobothrium sp. (in one host), bilocular metacestodes (in three hosts), and trilocular metacestodes (in three hosts). Cestodes predominated in the sample comprising 93.3 % of the total helminth number (table 2). Chionodraco rastrospinosus Four examined specimens of the ocellated icefi sh harboured 8 helminth species (from 4 to 7 species per host). Nematodes were represented by larval stages of Pseudoterranova sp. found in two hosts and Contracaecum sp. (in one host), and adults of A. nototheniae (in two hosts). Trematodes were represented by a single specimen of N. georgiensis. Cestodes at the metacestode stage predominated by their diversity (4 species) and occurrence. Bilocular and trilocular metacestodes were found in all hosts examined, Diphyllobothrium sp. was found in 3 hosts, one monolocular metacestode was found in one host. Cestodes comprised 88.5 % of all helminth specimens collected. Chaenodraco wilsoni One examined specimen of the spiny icefi sh harboured only bilocular (3 specimens) and trilocular (8 specimens) metacestodes; no other helminth species were recorded (table 2). Notothenia coriiceps Two specimens of the black rockcod harboured 13 helminth species (from 7 to 12 species per host) (table 2). A single specimen of the monogenean P. nototheniae was found on one host. Cestodes Diphyllobothrium sp. were found in both hosts; bilocular and trilocular metacestodes were found each in one black rockcod. Th ree trematode species infected one of two hosts examined. Acanthocephalans were represented by adults of A. megarhynchus in one host and larval Corynosoma spp., 4 species, each infecting both host specimens (table 2). Acanthocephalans composed the largest part of helminths in N. coriiceps; they comprised 72.0 % of the total number of helminths collected. Nematodes, 139Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica T a b le 2 . A bu nd an ce o f h el m in th sp ec ie s f ou nd in 1 2 sp ec ie s o f t el eo st fi sh es o ff th e So ut h O rk ne y Is la nd s a re a, W es t A nt ar ct ic a, in 2 02 0– 20 21 H el m in th sp ec ie s N um be r o f h el m in th sp ec im en s c ol le ct ed in fi sh sp ec ie s C G (n =3 4) PG (n =3 3) C A (n =2 2) N I (n =6 ) C R (n =4 ) C W (n =1 ) N C (n =2 ) N R (n =1 ) G G (n =5 ) N L (n =1 ) PC (n =2 ) G A (n =1 ) PL A T Y H EL M IN T H ES : M O N O G EN EA 1. Ps eu do be ne de ni a no to th en ia e Jo hn st on ,1 93 1 — — — — — — 1 1 — — — — PL A T Y H EL M IN T H ES : T R EM A T O D A 2. M ac vi ca ri a pe nn el li (L ei pe r & A tk in so n, 1 91 4) — 1 2 — — — 1 — — 1 — — 3. G en ol in ea b ow er si (L ei pe r e t A tk in so n, 1 91 4) — 1 8 — — — — — — — — 6 4. N eo le bo ur ia g eo rg ie ns is G ib so n, 1 97 6 88 31 9 59 4 — 1 — 6 — — 2 24 4 5. Le ci th as te r m ac ro co ty le S zi da t e t G ra ef e, 1 96 7 — — — — — — 1 — — — 29 10 6. Le pi da pe do n ga rr ar di (L ei pe r e t A tk in so n, 1 91 4) — — — — — — — — — 1 2 — PL A T Y H EL M IN T H ES : C ES T O D A 7. D ip hy llo bo th ri um sp . 27 7 62 9 13 91 4 23 — 19 5 49 4 19 27 1 8. M on ol oc ul ar m et ac es to de 7 47 31 — 1 — — — — — — 1 9. Bi lo cu la r m et ac es to de 26 2 12 41 10 1 41 71 3 5 — — 3 35 5 12 31 10 . T ri lo cu la r m et ac es to de 60 8 36 99 26 4 39 75 8 3 5 1 — 28 51 N EM A T O D A : C H R O M A D O R EA 11 . A sc ar op hi s n ot ot he ni ae Jo hn st on e t M aw so n, 1 94 5 5 3 2 — 2 — — — — — — — 12 . D ic he ly ne fr as er i ( Ba yl is , 1 92 9) — 20 8 11 8 — — — — 3 10 7 11 — — 13 . A ni sa ki s s p. — 11 4 — — — — 1 — — — — 14 . C on tr ac ae cu m sp . 16 34 1 33 7 6 8 — 2 53 6 — 7 10 3 15 . Ps eu do te rr an ov a sp . 3 66 6 21 44 — 11 — 85 72 4 5 68 — A C A N T H O C EP H A LA : P A LA EA C A N T H O C EP H A LA 16 . A sp er se nt is m eg ar hy nc hu s ( Li ns to w , 1 89 2) — — 5 — — — 20 — 2 — 2 — 17 . C or yn os om a bu llo su m (L in st ow , 1 89 2) — 59 83 — — — 2 43 2 43 7 2 18 . C . e va e Zd zi to w ie ck i, 19 84 — 11 34 0 — — — 22 4 4 3 4 4 — 19 . C . h am an ni (L in st ow , 1 89 2) — 7 32 0 — — — 46 2 40 4 8 — 20 . C . p se ud oh am an ni Z dz ito w ie ck i, 19 83 — — 26 — — — 25 2 — 2 — — 21 . C . s ha ck le to ni Z dz ito w ie ck i, 19 78 — — 5 — — — — — — — — — 22 . M et ac an th oc ep ha lu s r en ni ck i ( Le ip er & A tk in so n, 1 91 4) — 2 8 — — — — — — — 4 4 T ot al n um be r o f s pe ci es : 8 16 20 4 8 2 14 11 9 11 13 10 N um be r o f s pe ci es p er h os t,a ve ra ge (m in –m ax ) 4. 2 (1 –6 ) 6. 8 (3 –1 2) 8 (3 –1 3) 2. 5 (1 –4 ) 2 9. 5 (7 –1 2) 10 11 4. 2 (2 –6 ) 11 11 (1 0– 12 ) 6. 3 (4 –8 ) N o te . F is h sp ec ie s: C A — C ha en oc ep ha lu s a ce ra tu s, C G — C ha m ps oc ep ha lu s g un na ri , C R — C hi on od ra co ra st ro sp in os us , C W — C ha en od ra co w ils on i, G A — G ym no dr ac o ac ut ic ep s, G G — G ob io no to th en g ib be ri fr on s, N C — N ot ot he ni a co ri ic ep s, N I — N eo pa ge to ps is io na h, N L — N ot ot he ni op s la rs en i, N R — N . r os sii , P C — P ar ac ha en ic ht hy s ch ar co ti, P G — P se ud oc ha en ic ht hy s g eo rg ia nu s. 140 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin cestodes, and trematodes were less abundant and comprised 19.8 %, 6.1 %, and 1.8 % of the total helminth number, correspondingly. Notothenia rossii One examined specimen of the marbled rockcod appeared to be infected with 11 species of helminths: the monogenean P. nototheniae, 4 species of nematodes (larval Pseudoterranova sp., Contracaecum sp. and Anisakis sp., adult D. fraseri), trilocular metacestodes and Diphyllobothrium sp., and 4 species of larval acanthocephalans of the genus Corynosoma (table 2). In this host, nematodes were the most abundant group comprising 66.8 % of all helminths collected. Gobionotothen gibberifrons Five examined species of the humped rockcod harboured 9 helminth species (from 2 to 6 species per host). Th e nematode D. fraseri was found in all 5 host specimens, while Pseudoterranova sp. and Contracaecum sp. each infected one fi sh. Similarly, cestode Diphyllobothrium sp. was found in all hosts, while a single trilocular metacestode was in one host. Two host specimens appeared to be infected with the acanthocephalan A. megarhynchus. Corynosoma bullosum was found in one host, C. evae in two hosts, and C. hamanni in three hosts. Nematodes predominated among helminths of humped rockcod, they comprised 54.7 % of all helminths collected. Cestodes and acanthocephalans comprised 23.4 % and 22.0 % of all helminths, correspondingly. Nototheniops larseni One examined specimen of the painted notothen harboured 11 helminth species. Nematodes were represented by the larvae of Pseudoterranova sp. and the adults of D. fraseri, cestodes by Diphyllobothrium sp. and bilocular metacestodes. Trematodes were not abundant (table 2) and belonged to three species: M. pennelli, N. georgiensis, and L. garrardi. Four acanthocephalan species of the genus Corynosoma were found; in total, they comprised 66.2 % of all helminths collected. Parachaenichthys charcoti Both of the two examined specimens of the Antarctic dragonfi sh appeared to be infected with the larvae of two nematode species (Pseudoterranova sp. and Contracaecum sp.) and three species of cestodes: bilocular and trilocular metacestodes, and Diphyllobothrium sp.; from 10 to 12 helminth species parasitized one fi sh. Th e trematodes N.  georgiensis and L. macrocotyle were found in both host specimens, while L. garrardi was in one fi sh. Acanthocephalans were represented by adults of A. megarhynchus and M. rennicki (both in one host), and cystacanths of three species of the genus Corynosoma: C. hammani and C. evae in both hosts, and C. bullosum in one host. Among 13 helminth species collected from Antarctic dragonfi sh, bilocular metacestodes were the most abundant (table 2), and due to this cestodes predominated the community comprising 72.2 % of all helminths collected. Gymnodraco acuticeps Four examined specimens of the ploughfi sh harboured 10 helminth species (from 4 to 8 species per host). Nematodes were represented only by Contracaecum sp. found in all host individuals. Diphyllobothrium sp., bilocular and trilocular metacestodes were also found in all 4 hosts, while a single monolocular metacestode was found in one fi sh. Trematodes were not abundant (table 2); N. georgiensis and L. macrocotyle were found each in two host specimens, G. bowersi was found in one. Two hosts were infected each with 2 specimens of adult acanthocephalan M. rennicki; two cystacanths of C. bullosum were found in one fi sh. Cestodes strongly predominated in the ploughfi sh comprising 95.9 % of all helminths collected. 141Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica Chaenocephalus aceratus In the blackfi n icefi sh, 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. Th e 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 fi sh host on the immature stages. Th us, C. aceratus is considered to be a defi nitive host for 7 out of 19 helminth species recorded. Nematodes predominated in the helminth community of blackfi n icefi sh, they comprised 44.99 % of the total helminth number. Th e proportion of other groups of helminths was lower: 30.96 % for cestodes, 13.61 % for acanthocephalans, and 10.43 % for trematodes (fi g. 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. Th e 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. Champsocephalus gunnari In the mackerel icefi sh, only 8 helminth species were recorded (from 1 to 6 species per host): 1 species of trematodes, 4 species of cestodes and 3 species of nematodes (table 3). Spe- cies richness estimated using Chao1, jackknife, and bootstrap methods equalled 8 species. Th e diversity indices were 1.32 (Shannon), 0.67 (Simpson), and 0.63 (Pielou’s evenness). Only two helminth species, a digenean trematode N. georgiensis and a nematode A. no- totheniae parasitized C. gunnari on the adult stage; all other parasites were found on im- Fig. 1. Proportion (%) of four parasite taxa in three fi sh species from the South Orkney Islands area, West Antarctica. 142 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin mature stages. Th erefore, C. gunnari is considered to be a defi nitive host for 2 out of 8 hel- minth species recorded. Cestodes predominated in the helminth community of mackerel icefi sh; together they comprised 91.16 % of the total helminth number (fi g. 1). According to the prevalence (table 3), helminths of C. gunnari might be separated into two groups. Four species, namely Diphyllobothrium sp., bilocular and trilocular meta- cestodes, and the trematode N. georgiensis reached the prevalence of 79–94 %; thus, these species predominated in the helminth community. Other species occurred rarely, with the highest prevalence of 35.3 % in Contracaecum sp. Pseudochaenichthys georgianus In the South Georgia icefi sh, 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. Th e 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 lar- val stages. Th us, P. georgianus is considered to be a defi nitive host for 6 out of 16 helminth species recorded. As in the mackerel icefi sh, cestodes predominated in the helminth com- munity of P. georgianus; together they comprised 78.7 % of the total helminth number (fi g. 1). According to the prevalence of infection, 8 species predominated in the helminth com- munity in P.  georgianus (table 3). Bilocular and trilocular metacestodes had an infection prevalence higher than 95 %. Th e cestode Diphyllobothrium sp., the trematodes M. pennelli and N. georgiensis, the nematodes Contracaecum sp. and Pseudoterranova sp. had an infec- tion prevalence of 70–95 %. Th e 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 fi sh 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 %) (fi g. 2). Th e helminth species richness appeared to be much higher in fi shes from shallow- water (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 deep- water fi shes (table 5) revealed the highest similarity of helminth faunas in two shallow-wa- ter 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 %, respec- tively). Also, helminth faunas of deep-water populations of C. aceratus and P. georgianus were similar (Sørensen index 88.9 %). Th e 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 (fi g. 3) showed a clear division of groups of shallow- and deep- water fi sh species. According to the results of the SIMPER analysis, the overall dissimilarity between the helminth communities of shallow- and deep-water fi shes 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 fi shes with C. pseudohamanni and anisakid nematodes was more than 10–15 times higher, while deep-water fi shes had 168 times higher infection with trilocular metacestodes. 143Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica T a b le 3 . H el m in th sp ec ie s f ou nd in th re e te le os t fi s h sp ec ie s o ff th e So ut h O rk ne y Is la nd s a re a H el m in th sp ec ie s C ha en oc ep ha lu s a ce ra tu s (n = 2 2) C ha m ps oc ep ha lu s g un na ri (n = 3 4) Ps eu do ch ae ni ch th ys g eo rg ia nu s ( n = 22 ) P, % I M A P, % I M A P, % I M A PL A T Y H EL M IN T H ES : T R EM A T O D A 1. M ac vi ca ri a pe nn el li 4. 6 2. 0 0. 09 0 0 0 3. 0 1. 0 0. 03 2. G en ol in ea b ow er si 9. 1 4. 0 (1 –7 ) 0. 36 0 0 0 3. 0 1. 0 0. 03 3. N eo le bo ur ia g eo rg ie ns is 95 .5 28 .3 (2 –1 07 ) 27 .0 0 79 .4 3. 3 (1 –1 0) 2. 59 72 .7 13 .3 (1 –4 4) 9. 67 PL A T Y H EL M IN T H ES : C ES T O D A 4. D ip hy llo bo th ri um sp . 10 0. 0 63 .5 (5 –2 91 ) 63 .4 5 88 .2 9. 2 (1 –3 3) 8. 15 93 .4 21 .7 (1 –9 9) 20 .3 9 5. M on ol oc ul ar m et ac es to de 22 .7 6. 2 (1 –1 8) 1. 41 14 .7 1. 6 (1 –3 ) 0. 24 45 .5 3. 5 (1 –1 2) 1. 58 6. Bi lo cu la r m et ac es to de 63 .6 7. 3 (1 –2 4) 4. 64 91 .2 8. 5 (1 –2 7) 7. 71 96 .9 39 .8 (6 –3 43 ) 38 .6 4 7. T ri lo cu la r m et ac es to de 68 .2 17 .6 (1 –7 9) 12 .0 0 94 .1 19 .0 (2 –1 01 ) 17 .8 8 10 0. 0 1. 5 (9 –4 18 ) 12 1. 70 N EM A T O D A : C H R O M A D O R EA 8. A sc ar op hi s n ot ot he ni ae 9. 1 1. 0 (1 ) 0. 09 8. 8 1. 7 (1 –2 ) 0. 15 6. 1 1. 5 (1 –2 ) 0. 09 9. D ic he ly ne fr as er i 45 .5 11 .8 (1 –3 7) 5. 36 0 0 0 36 .7 17 .3 (1 –1 41 ) 6. 30 10 . A ni sa ki s s p. 13 .6 1. 3 (1 –2 ) 0. 18 0 0 0 9. 1 3. 4 (2 –7 ) 0. 33 11 . C on tr ac ae cu m sp . 72 .7 21 .1 (1 –8 6) 15 .3 2 35 .3 1. 3 (1 –2 ) 0. 47 84 .9 12 .2 (1 –7 2) 10 .3 3 12 . Ps eu do te rr an ov a sp . 95 .5 10 2. 1 (2 –3 94 ) 97 .4 5 8. 8 1. 0 0. 09 78 .8 25 .6 (1 –1 01 ) 20 .1 8 A C A N T H O C EP H A LA : P A LA EA C A N T H O C EP H A LA 13 . A sp er se nt is m eg ar hy nc hu s 4. 6 5 (5 ) 0. 23 0 0 0 0 0 0 14 . C or yn os om a bu llo su m 59 .1 6. 4 (2 –2 1) 3. 77 0 0 0 24 .2 7. 4 (1 –4 2) 1. 79 15 . C . e va e 45 .5 34 .0 (1 –2 94 ) 15 .4 5 0 0 0 12 .1 2. 8 (1 –6 ) 0. 33 16 . C . h am an ni 54 .6 26 .7 (1 –1 24 ) 14 .5 5 0 0 0 9. 1 2. 3 (1 –5 ) 0. 21 17 . C . p se ud oh am an ni 13 .6 8. 7 (2 –1 86 ) 1. 18 0 0 0 0 0 0 18 . C . s ha ck le to ni 13 .6 1. 7 (1 –3 ) 0. 23 0 0 0 0 0 0 19 . M et ac an th oc ep ha lu s r en ni ck i 4. 6 8. 0 (8 ) 0. 36 0 0 0 3. 0 2. 0 0. 06 N ot e. P ar am et er s o f fi s h in fe ct io n; P — p re va le nc e, I — in te ns ity (m ea n an d ra ng e in p ar en th es es ), M A — m ea n ab un da nc e. 144 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin Fig. 2. Proportion (%) of helminth species parasitizing three teleost fi shes from the South Orkney Islands area, West Antarctica on larval and adult stages. Fig 3. Cluster analysis of the similarity between the helminth communities of the shallow-water (SW) and deep- water (DW) populations of fi sh species determined by the Bray-Curtis index. Discussion Th e results obtained in our study expand the knowledge on the species composition of the fauna of teleost fi sh parasites in the South Orkney Islands region. Th ese data indicate a signifi cant role of teleost fi shes in food webs in the region as well as their key role in the life cycles of metazoan parasites of marine mammals and birds in West Antarctica. 145Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica All parasite species found were not specifi c to their fi sh hosts; all of them infected from two to 11 diff erent fi sh species. Th e high species richness of the parasite fauna of teleost fi shes was reported in diff erent regions of Antarctica (Palm et al., 2007; Zdzitowiecki, 2001 a; Zdzitowiecki and Laskowski, 2004; Laskowski and Zdzitowiecki, 2005; Shendryk et al., 2014; Oğuz et al., 2015; Münster et al., 2016, 2017; Kuhn et al., 2018; Alt et al., 2021; Kuzmina et al., 2022 a, b). Moreover, most of these studies reported the absence of host- specifi city in the helminths of Antarctic fi sh (Palm et al. 2007; Rohde and Heap, 1998; Zdzitowiecki, 2001 a; Laskowski and Zdzitowiecki, 2005; Oğuz et al., 2015; Kuhn et al., 2018; Kuzmina et al., 2022 a, b). Th e species richness in the helminth infracommunities varied from 2 to 13 species. Th e highest number of helminth species was recorded in C. aceratus (up to 13 species per one fi sh host), and in P. georgianus, P. charcoti, and N. сoriiceps (up to 12 species per host). Generally, the species composition and richness of the parasite communities in marine fi shes is determined by their feeding ecology, the depth of fi sh habitats and migrations (Klimpel et al. 2003, 2006 a, b; Rocka, 2006; Palm et al., 2007; Kuhn et al., 2018; Alt et al., 2021). In C. aceratus, P. georgianus, P. charcoti, N. larseni, and two Notothenia species, the high parasite species richness is connected with their less specialized feeding behaviour and refl ects their migrations from shallow coastal waters to the deep-sea habitats (Siegel, 1980 a, b; Gon and Heemstra 1990; Palm et al., 2007; Zdzitowiecki, 2001 a; Barrera-Oro, 2002; Laskowski and Zdzitowiecki, 2010; Kuhn et al., 2018; Alt et al., 2021). At the same time, fi sh species feeding mainly on Antarctic krill, such as C. gunnari, C. wilsoni, or N. ionah, have less rich parasite fauna (Hoogesteger and White, 1981; Kuhn et al., 2018). All twelve fi sh species examined were infected with both larval and adult helminths. Th e cestodes, anisakid nematodes, and acanthocephalans from the genus Corynosoma were found in fi shes on the larval stages; they used the teleosts as their intermediate or paratenic hosts. Moreover, in the largest samples of fi sh species (C. aceratus, C. gunnari, and P. geor- T a b l e 4. Species richness and abundance of helminths collected from teleost fi shes in shallow- or deep- water habitats in West Antarctica Fish species Number of specimens Depth of fi sh collection Number of helminths collected specimens species 1. Champsocephalus gunnari 34 107–665 m 1 267 8 2. Pseudochaenichthys georgianus 33 107–581 m 7 645 16 3. Chaenocephalus aceratus* 22 104–270 m 5 789 19 4. Notothenia coriiceps 78 10–30 m 15 451 27 5. Parachaenichtys charcoti 18 10–30 m 5 298 26 6. Chaenocephalus aceratus** 6 10–30 m 4 830 23 * Specimens of C. aceratus from the area of Orkney Islands; ** Specimens of C. aceratus from the Ukrainian Antarctic station (UAS) area. T a b l e 5. Similarity of helminth faunas between the shallow-water (SW) and deep-water (DW) fi sh populations based on the Sørensen index (%, below the diagonal) and the Bray-Curtis index (%, above the diagonal) Species N. coriiceps (SW) P. charcoti (SW) C. aceratus (SW) C. aceratus (DW) C. gunnari (DW) P. georgianus (DW) N. coriiceps (SW) – 72.2 68.6 46.9 20.0 33.3 P. charcoti (SW) 90.6 – 78.2 50.7 27.3 44.2 C. aceratus (SW) 88.0 89.8 – 55.6 24.6 43.9 C. aceratus (DW) 80.9 69.6 69.8 – 45.3 73.8 C. gunnari (DW) 45.7 47.1 45.2 57.1 – 64.8 P. georgianus (DW) 74.4 71.4 66. 7 88.9 66.7 – 146 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin gianus), the proportion of larvae in the parasite communities was from 62.5 % to 75 %. We did not calculate the exact proportion of larval stages in the helminth communities of the other nine fi sh species; however, larvae comprised more than 50 % of the total helminth number collected from every examined fi sh. In the present study, cestodes were found to be the dominant group of parasites; they were found in all 12 fi sh species. Moreover, the intensity of fi sh infection with cestodes might reach more than 400 specimens per host; especially highly infected was the deep-sea species P. georgianus with bilocular and trilocular metacestodes, as well as C. aceratus with Diphyllobothrium sp. (see table 3). For the tetrabothriid cestodes, Antarctic elasmobranchs and birds are the fi nal hosts; while the diphyllobothriid cestodes are the parasites of marine mammals (Rocka, 2006, 2017). In our study, the deep-sea fi sh species, such as C. wilsoni, G. acuticeps, P. charcoti, C. rastrospinosus, N. ionah, and C. gunnari were mainly infected with tetrabothriid metacestodes; the proportion of other taxonomic groups in the samples was much lower. Nematodes, especially Anisakidae were found to predominate in the helminth com- munities of demersal omnivorous fi sh species (C. aceratus, N. larseni, and Notothenia spp.); the same was observed in previous researches (Zdzitowiecki and Laskowski, 2004; Las- kowski and Zdzitowiecki, 2005; Palm et al., 2007; Alt et al., 2021; Kuzmina et al., 2021 b). In pelagic and deep-water fi sh species (C. gunnari, P. georgianus, N. ionah, C. rastrospinosus, C. wilsoni, etc.), the proportion of nematodes in helminth communities was much lower in our study as well as in the data published by other researchers (e. g., Kuhn et al., 2018). We believe that this is primarily due to the peculiarities of the diet of the demersal fi sh species, in which, according to literature data, krill, mysids, amphipods, copepods, and fi sh prevail (McKenna, 1991; Flores et al., 2004; Kock et al., 2013; Alt et al., 2021). At the same time, the deep-water fi sh species feed primarily on Antarctic krill (Euphausia superba) and, to a much lesser degree, on other euphausiids, mysids, and the hyperiids (Kock et al., 1994, 2013; Flores et al., 2004; Kock, 2005; Kuhn et al., 2018). Also, the infection of teleost fi shes with anisakid nematodes largely depends on the presence and density of marine mammals, mostly seals, which are the defi nitive hosts of these nematodes in the region (Klöser et al., 1992; Palm, 1999; McClelland, 2002; Palm et al., 2007; Rocka, 2004, 2006, 2017; Alt et al., 2021). Th e infection of teleost fi shes with digenean trematodes in our study was moderate; in four out of 12 fi sh species, trematodes were not found at all. Six species of trematodes were recorded, and Neolebouria georgiensis was the most prevalent; the rest of the species were found sporadically in single specimens (see table 3). All digenean species found were not host-specifi c; previously, all of them were reported in several teleost fi sh species in West Antarctica (Zdzitowiecki, 1991, 1998; Oğuz et al., 2015; Faltýnková et al., 2017). Most known species of Antarctic digeneans infecting fi sh hosts are associated with benthic habitats (Zdzitowiecki, 1988; 1998; Faltýnková et al., 2017; Alt et al., 2021); while pelagic fi shes are usually not infected with digeneans (Zdzitowiecki, 1991). Th e most probable intermediate hosts of the digeneans are copepods, amphipods, benthic gastropods or bivalves and annelids (Zdzitowiecki, 1988); thus, infection of demersal omnivorous fi shes with these trematodes is usually high. Th e absence of trematodes in three demersal fi sh species (C.  wilsoni, N.  rossii, and G.  gibberifrons) in our study is probably due to the small number of fi sh specimens examined and is connected with the feeding of these fi sh species mainly on Antarctic krill, which has been reported as not infected with helminths (Kagei et al., 1978; Zdzitowiecki, 1991). Th e infection of most fi sh species with the trematode N. georgiensis is apparently connected with the feeding of these fi sh on crustaceans of the family Mysidae, which are known as intermediate hosts of this digenean (Gaevskaya, 1982). Th e infection of studied fi sh with acanthocephalans varied widely; four fi sh species (C. gunnari, N. ionah, C. rastrospinosus, and C. wilsoni) were not found to harbour acan- 147Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica thocephalans at all, while C. aceratus was found to be infected with 7 species (with the intensity of up to 294 specimens for Corynosoma evae); N. coriiceps and P. charcoti were infected each with 5 acanthocephalan species. All Acanthocephala parasitic in Antarctic fi sh have two or three hosts in their life cycles (Rocka, 2006; Laskowski and Zdzitowiecki, 2017); the intermediate hosts for all acanthocephalans are crustaceans of the order Amphi- poda (Hoberg, 1986; Zdzitowiecki, 2001 b; Zdzitowiecki and Presler, 2001) which are an es- sential component of the diet of demersal fi sh. Th erefore, in Antarctica, acanthocephalans frequently parasitize demersal bottom-feeding fi sh hosts and are almost absent in fi shes with a pelagic lifestyle (Rocka, 2006; Laskowski and Zdzitowiecki, 2017; Alt et al., 2021; Kuzmina et al., 2021 a). In our study, two acanthocephalans specifi c for Antarctic teleost fi shes (A.  megarhynchus and M. rennicki) were found in 4 fi sh hosts each; the intensity of fi sh infection with these species was low, from one to 8 specimens. Acanthocephalans from the genus Corynosoma predominated in all fi shes infected with this group of hel- minths. Th e defi nitive hosts of Corynosoma spp. are marine mammals and birds; moreover, Corynosoma spp. are known to be specifi c to their defi nitive hosts (Hoberg, 1986; Zdzi- towiecki, 1984, 1996; Zdzitowiecki and White, 1996; Laskowski and Zdzitowiecki, 2017). Th us, the high level of fi sh infection recorded in our study indicated the presence of certain marine mammals: Mirounga leonina, Lobodon carcinophaga, Leptonychotes weddellii, and Hydrurga leptonyx in the examined marine habitats. Only two specimens of one Monogenea species, Pseudobenedenia nototheniae, were found in our study in two hosts: N. coriiceps and N. rossii; other ten fi sh species were not infected with monogeneans. Despite P. nototheniae being reported to have a rather wide range of fi sh hosts (see Klapper et al., 2017), here and in our previous studies performed at Argentine Islands area, this species was not found in any other fi sh except Notothenia spp. (Kuzmina et al., 2020, 2021 a). All fi sh species examined in the South Orkney Islands area were caught at depths from 60 m to more than 800 m (average fi shing/trawling depths varied from 104 m to 665 m); therefore, all 12 fi sh species studied in this work can be classifi ed as deep-sea species, compared to shallow-water fi sh species caught and examined near to the UAS “Akademik Vernadsky” at the depth of 10–30 m. Comparative analysis of diff erences in helminth communities of three deep-water and three shallow-water fi sh populations showed that the species richness of the helminth fauna in shallow-water fi shes is much higher, especially considering fi sh infection with digenean trematodes, acanthocephalans and anisakid nematodes. In the helminth fauna of deep-sea fi sh, larval stages of tetrabotriid cestodes — parasites of elasmobranchs were dominant groups of parasites. We agree with the opinion (see Campbell, 1983; Zdzitowiecki, 1990, 1998; Zdzitowiecki and Presler, 2001; Laskowski and Zdzitowiecki, 2005, 2010; Rocka, 2004, 2006; Palm et al., 1998, 2007; Shendryk et al., 2014; Alt et al., 2021) that the rich helminth fauna of shallow-water fi sh species is associated with the presence of a large number of helminth intermediate hosts (molluscs, small crustaceans) in shallow waters compared to deep-sea habitats. It is evident from our data that despite a much smaller number of studied specimens of the shallow- water population of C. aceratus (n = 6), the number of helminth species in this sample was higher compared to the sample from the deep-water population: 23 species versus 19 (see Kuzmina et al., 2021 a). Besides, the deep-sea fi shes C. gunnari and P. georgianus feed mainly on Antarctic krill (E. superba) which is not an intermediate host of helminths (Kagei et al., 1978; Zdzitowiecki, 1991). Th e results of the SIMPER analysis revealed four helminth species mostly infl uencing the diff erence between the helminth fauna of shallow- and deep-sea fi sh: nematodes Contracaecum sp. and Pseudoterranova sp., the acanthocephalan C. pseudohamanni, and trilocular metacestodes. We suppose that the high level of shallow-water fi sh infection with anisakids and C.  pseudohamanni is a result of the presence and high density of defi nitive hosts of these helminths, Weddell seals (L. weddellii), leopard seals 148 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin (H. leptonyx), and crabeater seal (L.  carcinophaga) in coastal waters of the Argentine Islands near the UAS “Akademik Vernadsky” (Dykyy and Peklo, 2012). In the deep waters near the South Orkney Islands, the density of these mammals is lower, therefore, the deep-sea fi sh species were 10–15 times less infected with anisakid nematodes and Corynosoma spp. At the same time, the high infection rates of tetrabotriid cestodes observed in deep-sea fi sh species indicate the important role of deep-sea teleosts in the life cycles of parasites of elasmobranchs in the West Antarctic. Our results confi rm the previously suggested indicator role of helminths for teleost fi sh population studies (Siegel, 1980 a, b; Kuhn et al., 2018; Kvach and Kuzmina, 2020; Kuzmina et al., 2022). More information on the parasite communities of fi sh populations is necessary for a reliable analysis of these data. Nevertheless, the results obtained in our study might be considered as the “basic point” for long-term monitoring parasitological studies in West Antarctica in future and the analysis of the changes in the Antarctic marine ecosystems caused by climatic and anthropogenic factors. Th is study was partially supported by the National Research Foundation of Ukraine (project number 2020.02/0074) and by the National Antarctic Scientifi c Center, Ministry of Education and Science of Ukraine (project number H/03-2021). References Alt, K. G., Cunze, S., Kochmann, J., Klimpel, S. 2021. Parasites of three closely related Antarctic fi sh species (Teleostei: Nototheniinae) from Elephant Island. Acta Parasitologica, https://doi.org/10.1007/s11686- 021-00455-8. Barrera-Oro, E. 2002. Th e role of fi sh in the Antarctic marine food web: diff erences between inshore and off shore waters in the southern Scotia Arc and west Antarctic Peninsula. Antarctic Science, 14 (4), 293–309. Bielecki, A., Rokicka, M., Ropelewska, E., Dziekońska-Rynko, J. 2008. Leeches (Hirudinida: Piscicolidae) parasites of Antarctic fi sh from Channichthyidae family. Wiadomości Parazytologiczne, 54, 345–348. Blanar, C. A., Munkittrick, K. R., Houlahan, J., Maclatchy, D. L., Marcogliese, D. J. 2009. Pollution and parasitism in aquatic animals: a meta-analysis of eff ect size. Aquatic Toxicology, 93 (1), 18–28. Brickle, P., MacKenzie, K., Pike, A. 2005. Parasites of the Patagonian toothfi sh, Dissostichus eleginoides Smitt 1898, in diff erent parts of the Subantarctic. Polar Biology, 28 (9), 663–671. Bush, A. O., Laff erty, K. D., Lotz, J. M., Shostak, A. W. 1997. Parasitology meets ecology on its own terms: Margolis et al. revisited. Journal of Parasitology, 83 (4), 575–583. Byers, J. E. 2021. Marine parasites and disease in the era of global climate change. Annual Review of Marine Science, 13, 397–420. Campbell, R. A. 1983. Parasitism in the deep sea. In: Rowe, G., ed. Th e Sea. Deep-sea biology. Wiley, New York, 473–552. Chown, S. L., Clarke, A., Fraser, C. I., Cary, S. C., Moon, K. L., McGeoch, M. A. 2015. Th e changing form of Antarctic biodiversity. Nature, 522 (7557), 431–438. Clarke, K. R., Gorley, R. N. 2006. PRIMER v6: User Manual/Tutorial (Plymouth Routines in Multivariate Ecological Research). PRIMER-E, Plymouth. Collins, M. A., Brickle, P., Brown, J., Belchier, M. 2010. Th e Patagonian toothfi sh: biology, ecology and fi shery. Advances in Marine Biology, 58, 227–300. De Broyer, C., Koubbi, P., Griffi ths, H. J., Raymond, B., Udekem d’Acoz, C. d’, Van de Putte, A. P., Danis, B., David, B., Grant, S., Gutt, J., Held, C., Hosie, G., Huettmann, F., Post, A., Ropert-Coudert, Y., eds. 2014. Biogeographic Atlas of the Southern Ocean. Scientifi c Committee on Antarctic Research, Cambridge, 1–498. Dykyy, I. V., Peklo, A. M. 2012. Seals of the Argentine Islands (Antarctica). Zbirnyk Prats Zoologichnogo Muzeju, 43, 104–116 [In Russian]. Eastman, J. T. 2000. Antarctic notothenioid fi shes as subjects for research in evolutionary biology. Antarctic Science, 12 (3), 276–287. Eastman, J. T. 2005. Th e nature of the diversity of Antarctic fi shes. Polar Biology, 28, 93–107. Faltýnková, A., Georgieva, S., Kostadinova, A., Bray, R. A. 2017. Biodiversity and Evolution of Digeneans of Fishes in the Southern Ocean. In: Klimpel, S., Kuhn, T., Mehlhorn, H., eds. Biodiversity and Evolution of Parasitic Life in the Southern Ocean. Parasitology Research Monographs, vol. 9. Springer, Cham, 49–75. Flores, H., Kock, K.-H., Wilhelms, S., Jones, C. D. 2004. Diet of two icefi sh species from the South Shetland Islands and Elephant Island, Champsocephalus gunnari and Chaenocephalus aceratus. Polar Biology, 27 (2), 119–129. 149Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica Gaevskaya, A. V. 1982. Th e discovery of the trematode metacercariae in mysids of the South Georgia Island. Nauchnye doklady vysshe shkoly. Biologicheskie nauki, 8, 27–29 [In Russian]. Gibson, D. I., Jones, A., Bray, R. A. 2002. Keys to the Trematoda. Volume 1. CABI & Natural History Museum, Wallingford, UK, 1–544. Gon, O., Heemstra, P. C. 1990. Fishes of the Southern Ocean, 1st edn. J. L. B. Smith Institute of Ichthyology, Grahamstown. Gordeev, I. I., Sokolov, S. G. 2016. Parasites of the Antarctic toothfi sh (Dissostichus mawsoni Norman, 1937) (Perciformes, Nototheniidae) in the Pacifi c sector of the Antarctic. Polar Research, 35, 29364. Hammer, Ø., Harper, D. A. T., Ryan, P. D. 2001. PAST: Paleontological Statistics Soft ware Package for Education and Data Analysis. Palaeontologia Electronica, 4, 9. Hechinger, R., Laff erty, K., Huspeni, T., Brooks, A., Kuris, A. 2007. Can parasites be indicators of free-living diversity? Relationships between species richness and the abundance of larval trematodes and local benthos and fi shes. Oecologia. 151, 82–92. Hoberg, E. P. 1986. Aspects of ecology and biogeography of Acanthocephala in Antarctic seabirds. Annales de parasitologie humaine et compare, 61, 199–214. Hoogesteger, J. N., White, M. G. 1981. Notes on parasite infestation of inshore fi sh at Signy Island, South Orkney Islands. BritishAntarctic Survey Bulletin, 54, 23–31. Hudson, P. J., Dobson, A. P., Laff erty, K. D. 2006. Is a healthy ecosystem one that is rich in parasites? Trends in Ecology and Evolution, 21 (7), 381–385. Jones, A., Bray, R. A., Gibson, D. I. 2005. Keys to the Trematoda. Volume 2. CABI & Natural History Museum, Wallingford, UK, 1–768. Kagei, N., Asano, K., Kihata, M. 1978. On the examination against the parasites of Antarctic krill, Euphausia superba. Th e Scientifi c Reports of the Whales Research Institute, 30, 311—313. Klapper, R., Münster, J., Kochmann, J., Klimpel, S., Kuhn, T. 2017. Biodiversity and Host Specifi city of Monogenea in Antarctic Fish Species. In: Klimpel, S. et al., eds. Biodiversity and Evolution of Parasitic Life in the Southern Ocean. Parasitology Research Monographs, vol. 9, 33–47. Klimpel, S., Seehagen, A., Palm H. W. 2003. Metazoan parasites and feeding behaviour of four small-sized fi sh species from the central North Sea. Parasitology Research, 91, 290–297. Klimpel, S., Rückert, S., Piatkowski, U., Palm, H. W., Hanel, R. 2006a. Diet and metazoan parasites of silver scabbard fi sh Lepidopus caudatus from the Great Meteor Seamount (North Atlantic). Marine Ecology Progress Series, 315, 249–257. Klimpel, S., Palm, H. W., Busch, M. W., Kellermanns, E., Rückert, S. 2006b. Fish parasites in the Arctic deep- sea: Poor diversity in meso-bathypelagial vs. heavy parasite load in a demersal fi sh. Deep-Sea Research Part I, 53, 1167–1181. Klöser, H., Plötz, J., Palm, H. W., Bartsch, A., Hubold, G. 1992. Adjustment of anisakid nematode life cycles to the high Antarctic food web as shown by Contracaecum radiatum and C. osculatum in the Weddell Sea. Antarctic Sciences, 4, 171–178. Kock, K.-H. 1992. Antarctic fi sh and fi sheries. Cambridge University Press, 1–359. Kock, K-H. 2005. Antarctic icefi shes (Channichthyidae): a unique family of fi shes. A review, Part I. Polar Biology, 28 (12), 862–895. Kock, K-H., Wilhelms, S., Everson, I., Groger, J. 1994. Variations in the diet composition and feeding intensity of mackerel icefi sh Champsocephalus gunnari at South Georgia (Antarctic). Marine Ecology Progress Series, 108, 43–58. Kock, K-H, Gröger, J., Jones, C. D. 2013. Interannual variability in the feeding of ice fi sh (Notothenioidei, Channichthyidae) in the southern Scotia Arc and the Antarctic Peninsula region (CCAMLR Subareas 48.1 and 48.2). Polar Biology, 36 (10), 1451–1462. Kuhn, T., Zizka, V. M. A., Münster, J., Klapper, R., Mattiucci, S., Kochmann, J., Klimpel, S. 2018. Lighten up the dark: metazoan parasites as indicators for the ecology of Antarctic crocodile icefi sh (Channichthyidae) from the north-west Antarctic Peninsula. PeerJ. 6: e4638. Kuzmina, T. A., Salganskij, O. O., Lisitsyna, O. I., Korol, E. M. 2020. Helminths of Antarctic rockcod Notothenia coriiceps (Perciformes, Nototheniidae) from the Akademik Vernadsky Station area (Argentine Islands, West Antarctica): new data on the parasite community. Zoodiversity, 54 (2), 99–110. Kuzmina, T. A., Laskowski, Z., Salganskij, O. O., Zdzitowiecki, K., Lisitsyna, O. I., Kuzmin, Y. 2022. Helminth assemblages of the Antarctic black rockcod, Notothenia coriiceps (Actinopterygii: Nototheniidae) in coastal waters near Galindez Island (Argentine Islands, West Antarctic): temporal changes in the endoparasite community. Acta Parasitologica, 67(1):207-217. Kuzmina, T. A., Dykyy, I. V., Salganskij, O. O., Lisitsyna, O. I., Korol, E. M., Kuzmin, Yu. I. 2021 a. Helminth diversity in teleost fi shes from the area of the Ukrainian Antarctic station “Akademik Vernadsky”, Argentine Islands, West Antarctica. Zoodiversity, 55 (3), 251–264. Kuzmina, T. A., Salganskij, O. O., Dykyy, I. V., Lisitsyna, O. I., Korol, E. M., Faltýnková, A., Kuzmin, Y. I. 2021 b. Helminths of the Antarctic dragonfi sh, Parachaenichthys charcoti (Perciformes, Notothenioidei, Bathydraconidae) Studied near Galindez Island (Argentine Islands, West Antarctica). Acta Parasitologica, 66 (4), 1424–1430. 150 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin Kvach, Y., Kuzmina, T. 2020. Parasitological research in Antarctica: review of the issues and future prospects. Ukrainian Antarctic Journal, 1, 102–110 [In Ukrainian]. Laskowski, Z., Zdzitowiecki, K. 2005. Th e helminth fauna of some notothenioid fi shes collected from the shelf of Argentine Islands, West Antarctica. Polish Polar Research, 26 (4), 315–324. Laskowski, Z., Zdzitowiecki, K. 2010. Contribution to the knowledge of the infection with Acanthocephala of a predatory Antarctic ice-fi sh Chaenocephalus aceratus. Polish Polar Research, 31, 303–308. Laskowski, Z., Zdzitowiecki, K. 2017. Acanthocephalans in Sub-Antarctic and Antarctic. In: Klimpel S., Kuhn T., Mehlhorn H. , eds. Biodiversity and Evolution of Parasitic Life in the Southern Ocean. Parasitol- ogy Research Monographs, vol. 9. Springer, Cham, 141–182. Laskowski, Z., Rocka, A., Zdzitowiecki, K., Ozouf-Costaz, C. 2007. Occurrence of endoparasitic worms in dusky notothen, Trematomus newnesi (Actinopterygii Nototheniidae), at Adelie Land, Antarctica. Polish Polar Research, 28 (1), 37–42. Marcogliese, D. J. 2002. Food webs and the transmission of parasites to marine fi sh. Parasitology. 124 Suppl., S83–99. Marcogliese, D. J. 2016. Th e Distribution and abundance of parasites in aquatic ecosystems in a changing climate: more than just temperature. Integrative and Comparative Biology, 56 (4), 611–619. McClelland, G. 2002. Th e trouble with sealworms (Pseudoterranova decipiens species complex, Nematoda): a review. Parasitology, 124, 183–203. McKenna, Jr., J. E., 1991. Trophic relationships within the Antarctic demersal fi sh community of South Georgia Island. Fishery Bulletin, 89, 643e654. Mozgovoy, A. A. 1951. Ascaridata of animals and man, and the diseases caused by them. Osnovy nematodologii. Vol. II. Izd-vo AN SSSR, Moskva, 1–616 [In Russian]. Muñoz, G., Cartes, F. D. 2020. Endoparasitic diversity from the Southern Ocean: is it really low in Antarctic fi sh? Journal of Helminthology, 94, e180, 1–10. Münster, J., Kochmann, J., Klimpel, S., Klapper, R., Kuhn, T. 2016. Parasite fauna of Antarctic Macrourus whitsoni (Gadiformes: Macrouridae) in comparison with closely related macrourids. Parasites & Vectors, 9, 403. Münster, J., Kochmann, J., Grigat, J., Klimpel, S., Kuhn T. 2017. Parasite fauna of the Antarctic dragonfi sh Parachaenichthys charcoti (Perciformes: Bathydraconidae) and closely related Bathydraconidae from the Antarctic Peninsula, Southern Ocean. Parasites & Vectors, 10, 235. Near, T. J. 2009. Notothenioid fi shes (Notothenioidei). In: Hedges, S. B., Kumar, S., eds. Th e Timetree of Life. Oxford University Press, 339–343. Near, T. J., Dornburg, A., Kuhn, K. L., Eastman, J. T., Pennington, J. N., Patarnello, T., Zane, L., Fernández, D. A., Jones, C. D. 2012. Ancient climate change, antifreeze, and the evolutionary diversifi cation of Antarctic fi shes. Proceedings of the National Academy of Sciences of the United States of America, 109 (9), 3434–3439. Oğuz, M. C., Heckmann, R. A., Cheng, C. H. C., El-Naggar, A., Tepe, Y. 2012. Ecto and endoparasites of some fi shes from the Antarctic Region. Scientia Parasitologica, 13 (3), 119–128. Oğuz, M. C., Tepe, Y., Belk, M. C., Heckmann, R. A., Aslan, B., Gürgen, M., Bray, R. A., Akgül, Ü. 2015. Metazoan parasites of Antarctic fi shes. Turkiye Parazitoloji Derneği, 39, 174–178. Palm, H. W. 1999. Ecology of Pseudoterranova decipiens (Krabbe, 1878) (Nematoda: Anisakidae) from Antarctic waters. Parasitology Research, 85, 638–646. Palm, H. W., Reimann, N., Spindler, M., Plötz, J. 1998. Th e role of the rock cod Notothenia coriiceps (Richardson, 1844) in the life-cycle of Antarctic parasites. Polar Biology, 19 (6), 399–406. Palm, H. W., Klimpe, S., Walter, T. 2007. Demersal fi sh parasite fauna around the South Shetland Islands; high species richness and low host specifi city in deep Antarctic waters. Polar Biology, 30 (12), 1513–1522. Parker, E., Jones, C. D., Arana, P. M., Alegría, N. A., Sarralde, R., Gallardo, F. , Phillips, A. J., Williams, B. W., Dornburg, A. 2020. Infestation dynamics between parasitic Antarctic fi sh leeches (Piscicolidae) and their crocodile icefi sh hosts (Channichthyidae). Polar Biology, 43, 665–677. Parukhin, A. M. 1986. Helminthofauna peculiarities of commercial Nototheniodei from the SubAntarktic region of the Indian Ocean. Vestnik Zoologii, 3, 6–10 [In Russian]. Parukhin, A. M., Lyadov, V. N. 1982. Helminth fauna of food Nototheniidae fi shes from Kerguelen subregion. Ekologija Morya, Kiev, 10, 49–57 [In Russian]. Poulin, R. 2006. Global warming and temperature-mediated increases in cercarial emergence in trematode parasites. Parasitology, 132 (1), 143–151. Poulin, R., Mouritsen, K. N. 2006. Climate change, parasitism and the structure of intertidal ecosystems. Journal of Helminthology, 80 (2), 183–191. Rocka, A. 1999. Biometrical variability and occurrence of Ascarophis nototheniae (Nematoda, Cystidicolidae), a parasitic nematode of Antarctic and subantarctic fi shes. Acta Parasitologica, 44 (4), 188–192. Rocka, A. 2003. Cestodes of the Antarctic Fishes. Polish Polar Research, 24 (4), 261–276. Rocka, A. 2004. Nematodes of the Antarctic fi shes. Polish Polar Research, 25 (2), 135–152. Rocka, A. 2006. Helminths of Antarctic fi shes: Life cycle biology, specifi city and geographical distribution. Acta Parasitologica, 51, 26–35. 151Helminth Diversity in Teleost Fishes from the South Orkney Islands Region, West Antarctica Rocka, A. 2017. Cestodes and Nematodes of Antarctic Fishes and Birds. In: Klimpel, S., Kuhn, T., Mehlhorn, H., eds. Biodiversity and Evolution of Parasitic Life in the Southern Ocean. Parasitology Re- search Monographs, vol 9. Springer, Cham, 77–107. Rohde, K., Heap, M. 1998. Latitudinal diff erences in species and community richness and in community structure of metazoan endo- and ectoparasites of marine teleost fi sh. International Journal for Parasitology, 28, 461–474. Sala, E., Knowlton, N. 2006. Global Marine Biodiversity Trends. Annual Review of Environment and Resources, 31, 93–122. Shendrik, T. V., Giginyak, Y. G., Borodin, O. I. 2014. Helminthofauna Trematomus newnesi (Actinopterygii; Nototheniidae), obtained from the Bay of Azure, Antarctica. Trudy BGU, 9 (2), 32–38. Siegel, V. 1980 a. Parasite tags for some Antarctic channichthyid fi sh. Archiv für Fischereiwissenschaft , 31, 97– 103. Siegel, V. 1980 b. Quantitative investigations on parasites of Antarctic channichthyid and nototheniid fi shes. Meeresforschung – Reports on Marine Research, 28, 146–156. Smith, W. O. Jr., Ainley, D. G., Cattaneo-Vietti, R. 2007. Trophic interactions within the Ross Sea continental shelf ecosystem. Philosophical Transactions of the Royal Society B: Biological Sciences, 362, 95–111. Sokolov, S. G., Gordeev, I. I., Atopkin, D. M. 2016. Redescription of trematode Gonocerca muraenolepisi Pa- rukhin et Lyadov 1979 (Hemiuroidea, Derogenidae), a body cavity parasite of Antarctic fi shes, with a discussion of its phylogenetic position. Invertebrate Zoology, 13 (2), 191–202. Sokolov, S. G., Lebedeva, D. I., Gordeev, I. I., Khasanov, F. K. 2019. Zdzitowieckitrema incognita gen. et sp. nov. (Trematoda, Xiphidiata) from the Antarctic fi sh Muraenolepis marmorata Günther, 1880 (Gadiformes: Muraenolepidae): ordinary morphology but unclear family affi liation. Marine Biodiversity, 49, 451–462. Swan, D. C. 1936. Berlese’s Fluid: Remarks upon its Preparation and use as a Mounting Medium. Bulletin of Entomological Research, 27 (3), 389–391. Targett, T. E. 1981. Trophic Ecology and Structure of Coastal Antarctic Fish Communities. Marine Ecology Progress Series, 4, 243–263. Th ompson, R. M., Mouritsen, K. N., Poulin, R. 2004. Importance of parasites and their life cycle characteristics in determining the structure of a large marine food web. Journal of Animal Ecology, 74, 77–85. Weber, E. P. 3rd, Govett, P. 2009. Parasitology and necropsy of fi sh. Compendium on Continuing Education for the Practising Veterinarian, 31 (2). E12. Wojciechowska, A. 1993. Th e tetraphyllidean and tetrabothriid cercoids from Antarctic bony fi shes. I. Mor- phology. Identifi cation with adult forms. Acta Parasitologica, 38 (1), 15–22. Zdzitowiecki, K. 1979. Digenetic trematodes in alimentary tracts of fi shes of South Georgia and South Shetland Islands (Antarctica). Acta Ichthyologica et Piscatoria, 9 (1), 15–30. Zdzitowiecki, K. 1983. Antarctic acanthocephalans of the genus Metacanthocephalus. Acta Parasitologica Po- lonica, 28 (4), 417–437. Zdzitowiecki, K. 1984 a. Some Antarctic acanthocephalans of the genus Corynosoma parasitizing Pinnipedia, with descriptions of three new species. Acta Parasitologica Polonica, 29 (4), 359–377. Zdzitowiecki, K. 1984 b. Redescription of Corynosoma hamanni (Linstow, 1892) and description of C. pseudo- hamanni sp. n. (Acanthocephala) from the environs of the South Shetlands (Antarctic). Acta Parasito- logica Polonica, 29 (4), 379–393. Zdzitowiecki, K. 1987. Acanthocephalans of marine fi shes in the regions of South Georgia and South Orkneys (Antarctic). Acta Parasitologica Polonica, 31 (4), 211–217. Zdzitowiecki, K. 1988. Occurrence of digenetic trematodes in fi shes off South Shetlands (Antarctic). Acta Para- sitologica Polonica, 33, 155–167. Zdzitowiecki, K. 1990. Occurrence of acanthocephalans in fi shes of the open sea off the South Shetlands and South Georgia (Antarctic). Acta Parasitologica Polonica, 35, 131–141. Zdzitowiecki, K. 1991. Occurrence of digeneans in open sea fi shes off the South Shetland Islands and South Georgia, and a list of fi sh digeneans in the Antarctic. Polish Polar Research, 12 (1), 55–72 Zdzitowiecki, K. 1996. Acanthocephala in fi sh in the Weddell Sea (Antarctica). Acta Parasitologica Antarctic, 41 (3), 199–203. Zdzitowiecki, K. 1998. Diversity of Digenea, parasites of fi shes in various areas of the Arctic. In: Di Prisco, G., Pisano, E., Clarke, A., eds. Fishes of Antarctica. Milano, Springer, 87–94. Zdzitowiecki, K. 2001 a. Occurrence of endoparasitic worms in fi sh, Parachaenichthys charcoti (Bathydraconidae), off the South Shetland Islands (Antarctica). Acta Parasitologica, 46 (1), 18–23. Zdzitowiecki, K. 2001 b. Acanthocephala occurring in intermediate hosts, amphipods, in Admiralty Bay (South Shetland Islands, Antarctica). Acta Parasitologica, 46 (3), 202–207. Zdzitowiecki, K., Cielecka, D. 1997 a. Digenea of fi shes of the Weddell Sea. II. Th e Genus Macvicaria (Opecoelidae). Acta Parasitologica, 42 (2), 77–83. Zdzitowiecki, K., Cielecka, D. 1997 b. Digenea of fi shes of the Weddell Sea. III. Th e Lepocreadiidae (genera Neolepidapedon and Lepidapedon), parasites of Notothenioidea, Acta Parasitologica, 42 (2), 84–91. Zdzitowiecki, K., Laskowski, Z. 2004. Helminths of an Antarctic fi sh, Notothenia coriiceps, from the Vernadsky Station (Western Antarctica) in comparison with Admiralty Bay (South Shetland Islands). Helminthologia, 41 (4), 201–207. 152 T. A. Kuzmina, O. O. Salganskiy, K. O. Vishnyakova, J. Ivanchikova, O. I. Lisitsyna, E. M. Korol, Yu. I. Kuzmin Zdzitowiecki, K., Presler, P. 2001. Occurrence of, Acanthocephala in intermediate hosts Amphipoda, in Admiralty Bay, South Shetland Islands, Antarctica. Polish Polar Research, 22, 205–212. Zdzitowiecki, K., White, M. G. 1992. Digenean Trematoda infection of inshore fi sh at South Georgia. Antarctic Science, 4 (1), 51–55. Received 11 January 2022 Accepted 30 March 2022