Fig. 1.
Sampling sites, Danube River (https://www.google.bg/maps/place/Видин – https://www.google.bg/maps/place/Vidin)
Table 1.
Metric data (L – total length, H – maximum height, W – body weight) of the studied specimens of Babka gymnotrachelus, Neogobius fluviatilis, Neogobius melanostomus.
| The Danube River | L (cm) | H (cm) | W (g) | |
|---|---|---|---|---|
| Babka gymnotrachelus N = 9 | min – max | 8.8 – 16 | 1.2 – 2.5 | 4 – 37 |
| Mean ± SD | 10.83 ± 2.24 | 1.73 ± 0.46 | 12.78 ± 10.60 | |
| Neogobius fluviatilis N = 48 | min – max | 5.4 – 12 | 0.8 – 2.4 | 1 – 18 |
| Mean ± SD | 8.61 ± 1.39 | 1.39 ± 0.31 | 4.49 ± 3.23 | |
| Neogobius melanostomus N = 15 | min – max | 6.3 – 11.6 | 1.1 – 2.4 | 2 – 13 |
| Mean ± SD | 8.23 ± 1.66 | 1.56 ± 0.34 | 6.07 ± 3.49 | |
Table 2.
Distribution of established helminth species in B. gymnotrachelus, N. fluviatilis, and N. melanostomus from four biotopes located in the upper section of the Danube River in Bulgaria.
| Fish species | Babka gymnotrachelus N = 9 | Neogobius fluviatilis N = 48 | Neogobius melanostomus N = 15 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Sampling sites Helminth species | Kudelin N = 5 | Novo selo N = 4 | Kudelin N = 31 | Koshava N = 5 | Novo selo N = 11 | Kutovo N = 1 | Kudelin N = 8 | Koshava N = 3 | Novo selo N = 4 |
| Nicolla skrjabini (Iwanitzky, 1928) Dollfus, 1960 | • | • | • | • | • | • | • | ||
| Acanthocephalus anguillae (Müller, 1780) Lühe, 1911 | • | ||||||||
| Acanthocephalus lucii (Müller, 1776) Lühe, 1911 | • | • | • | • | • | • | |||
| Eustrongylides excisus Jägerskiöld, 1909 | • | • | • | • | |||||
| Pomphorhynchus laevis (Zoega in Müller, 1776) Porta, 1908 | • | ||||||||
| Contracaecum sp. | • | ||||||||
Table 3.
Species diversity and ecological indices in the helminth community of Babka gymnotrachelus from the Danube River (N – number of investigated fish; n – number of infected fish; p – number of fish helminths; MI – mean intensity; MA – mean abundance; P% – prevalence; R – range)
| Babka gymnotrachelus (N = 5 / Kudelin) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 1 | 52 | 52.00 | 10.40 | 20.00 | 52 |
| Acanthocephalus lucii | 2 | 33 | 16.50 | 6.60 | 40.00 | 3–30 |
| Eustrongylides excisus | 2 | 3 | 1.50 | 0.60 | 40.00 | 1–2 |
| Babka gymnotrachelus (N = 4 / Novo selo) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 3 | 292 | 97.33 | 73.00 | 75.00 | 15–237 |
| Acanthocephalus lucii | 3 | 59 | 19.67 | 14.75 | 75.00 | 2–39 |
| Eustrongylides excisus | 1 | 9 | 9.00 | 2.25 | 25.00 | 9 |
Table 4.
Species diversity and ecological indices in the helminth community of Neogobius fluviatilis from the Danube River (N – number of investigated fish; n – number of infected fish; p – number of fish parasites; MI – mean intensity; MA – mean abundance; P% – prevalence; R – range)
| Neogobius fluviatilis (N = 31 / Kudelin) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 15 | 47 | 3.13 | 1.52 | 48.39 | 1–17 |
| Acanthocephalus lucii | 10 | 55 | 5.50 | 1.77 | 32.26 | 1–38 |
| Eustrongylides excisus | 8 | 13 | 1.63 | 0.42 | 25.81 | 1–2 |
| Neogobius fluviatilis (N = 11 / Novo selo) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 6 | 9 | 1.50 | 0.82 | 54.55 | 1–2 |
| Acanthocephalus lucii | 1 | 1 | 1.00 | 0.09 | 9.09 | 1 |
| Eustrongylides excisus | 1 | 1 | 1.00 | 0.09 | 9.09 | 1 |
| Neogobius fluviatilis (N = 1 / Kutovo) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 1 | 3 | 3.00 | 3.00 | 100.00 | 3 |
Table 5.
Species diversity and ecological indices in the helminth community of Neogobius melanostomus from the Danube River (N – number of investigated fish; n – number of infected fish; p – number of fish parasites; MI – mean intensity; MA – mean abundance; P% – prevalence; R – range)
| Neogobius melanostomus (N = 8 / Kudelin) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 5 | 16 | 3.20 | 2.00 | 62.50 | 1–8 |
| Acanthocephalus lucii | 5 | 123 | 24.60 | 15.38 | 62.50 | 1–90 |
| Contracaecum sp. | 1 | 1 | 1.00 | 0.13 | 12.50 | 1 |
| Neogobius melanostomus (N = 3 / Koshava) Helminth species | n | p | MI | MA | P% | R |
| Nicolla skrjabini | 1 | 1 | 1.00 | 0.33 | 33.33 | 1 |
| Acanthocephalus anguillae | 1 | 38 | 38.00 | 12.67 | 33.33 | 38 |
| Pomphorhynchus laevis | 1 | 11 | 11.00 | 3.67 | 33.33 | 11 |
| Neogobius melanostomus (N = 4 / Novo selo) Helminth species | n | p | MI | MA | P% | R |
| Acanthocephalus lucii | 1 | 1 | 1.00 | 0.25 | 25.00 | 1 |
Table 6.
Species composition of parasites of Babka gymnotrachelus, Neogobius fluviatilis, Neogobius melanostomus from the Danube River and its basin in different countries (* – endohelminths also found in the present study from the respective fish species)
| Fish species | Authors | Sampling sites | Endohelminth species |
|---|---|---|---|
| Babka gymnotrachelus | Ondračková et al. (2012) | Danube River, Bulgaria – Vidin town, Koshava and Gomotartsi villages | *N. skrjabini (MA = 3.41, P% = 84.4); Raphidascaris acus (Boch, 1779); *E. excisus (MA = 0.41, P% = 28.1); P. laevis |
| Neogobius fluviatilis | Margaritov (1966) | Danube River, Bulgaria – between the mouth of the Timok River and Novo Selo village | *N. skrjabini; P. laevis; C. bidentatum; Rhabdochona sp.; Acanthocephala gen sp. |
| Kakacheva-Avramova (1977) | Danube River, Bulgaria | *N. skrjabini; P. laevis; C. bidentatum | |
| Kakacheva-Avramova et al. (1978) | Danube River, Bulgaria – Vidin and Lom towns | *N. skrjabini; C. bidentatum; Contracaecum sp. (larvae); Rhabdochona sp. (larvae); P. laevis | |
| Molnár & Székely (1995) | Lake Balaton, Hungary | Ligula sp. (larvae); Proteocephalus sp.; Ang. crassus (larvae) | |
| Ondračková et al. (2005) | Hron River, Slovakia | *N. skrjabini; P. laevis (larvae); Contracaecum sp. (larvae); R. acus (larvae) | |
| Molnár (2006) | Danube River, Hungary | *N. skrjabini; P. laevis; R. acus (larvae) | |
| Kosuthova et al. (2009) | Danube River, Slovakia | *N. skrjabini; P. laevis | |
| Ondračková et al. (2012) | Danube River, Bulgaria – Koshava and Gomotartsi villages | *N. skrjabini (MA = 8.76, P% = 52.6); *E. excisus (MA = 0.32, P% = 15.8); P. laevis | |
| Kirin et al. (2013) | Danube River, Bulgaria – Vetren village | Pomphorhynchus tereticollis (Rudolphi, 1809) Meyer, 1932 | |
| Neogobius melanostomus | Ondračková et al. (2005) | Danube River, Slovakia | *N. skrjabini; *P. laevis (larvae); R. acus (larvae) |
| Molnár (2006) | Danube River, Hungary | *N. skrjabini; *P. laevis | |
| Kosuthova et al. (2009) | Danube River, Slovakia | *P. laevis | |
| Mühlegger et al. (2010) | Danube River, Austria | *N. skrjabini; *Ac. lucii | |
| Neogobius melanostomus | Ondračková et al. (2010) | Danube River, Austria – Orth an der Donau | *P. laevis; R. acus |
| Danube River, Bulgaria – Vidin town | *P. laevis (MA = 54.5, P% = 96.4; MA = 97.5, P% = 100); R. acus | ||
| Francová et al. (2011) | Danube River, Austria – Orth an der Donau | *N. skrjabini; *P. laevis; E. excisus (larvae); R. acus (larvae) | |
| Danube River, Slovakia – Gabčíkovo | *P. laevis; R. acus (larvae); C. lacustris | ||
| Danube River, Bulgaria – Vidin and Ruse towns | *N. skrjabini (MA = 0.1, P% = 3.6 for Vidin; MA = 0.3, P% = 7.9 for Ruse); Nicolla sp.; *P. laevis (MA = 43.3, P% = 99.4 for Vidin; MA = 22.1, P%=94.7 for Ruse); E. excisus, larvae; R. acus, larvae | ||
| Atanasov (2012) | Danube River, Bulgaria – Archar, Dobri Dol and Gomotartsi villages | E. excisus | |
| Ondračková et al. (2012) | Danube River, Austria – Orth an der Donau | *N. skrjabini; R. acus; *P. laevis | |
| Danube River, Bulgaria – Vidin town | *N. skrjabini (MA = 0.11, P% = 5.3); R. acus; *P. laevis (MA = 18.4, P% = 94.7); E. excisus | ||
| Ondračková et al. (2021) | Morava River, the Czech Republic | Eustrongylides spp. (larvae) |
Fig. 2.
Comparative examination of the ecological indices (MI, MA, and P%) of Nicolla skrjabini and Acanthocephalus lucii from the upper section of the Danube River in Bulgaria.