92
K. Zdzitowiecki
present data, each is specific to one higher taxon of fishes, the first one to
the superfamily Notothenioidei, the second to the family Liparididae.
Other representatives of Monorchiidae and Fellodistomidae (not listed
here) were recorded in the SubAntarctic.
Data on the diversity of Digenea of fishes in different areas of the
Antarctic (Table 5) should be regarded as preliminary ones, as they are
strongly dependent upon the extent of research. For example, the smallest
number of digenean species (9) has been reported from the Ross Sea, but
almost all data are based on examinations of fishes caught in relatively
shallow waters (down to ca. 200 m) with the only exception being one
zoarcid species occurring at a depth of ca. 600 m. The greatest number of
species (22) has be-en-reported from the Weddell Sea, where a lot of deep
water fish species have been investigated, including many others than
Notothenioidei. More digenean species were recorded in the South Georgia
area than off the South Shetland Islands. It is clearly dependent upon the
research on muraenolepidids in the former area, as numbers of parasites of
Notothenioidei are similar in both areas. Data from the Indian sector of the
Southern Ocean are considerably less numerous than those from the
Weddell Sea. They are based mainly on material collected over 60 years
ago and elaborated 40 years later [9], with additional data based on a
limited number of fishes received by the present author from Russian,
Italian and French ichthyologists. Thus, a low number of parasite species
appears to be associated with too poor investigations. It should be noted
that intensities of digenean infections are greater in coastal zones
(especially in fjords) in the Western Antarctic, reaching to more than 1000
parasites in some Notothenia neglecta and N rossii, than in the open sea
and deep waters, especially in the Eastern Antarctic (normally several,
rarely more than ten parasites in one fish).
Table 5. Species diversity and specificity offish Digenea in different areas of the Antarctic
Area and specificity
Number of species
Parasitic in Notothenioidei
Parasitic in other fishes
Total
Ross Sea
Indian sector
Weddell Sea
South Shetlands
South Georgia
Specific parasites
Nonspecific parasites
Total
9
10
13 (14)
15
13 (15)
15
12 (15)
27 (30)
2
6
8
4
9
17 (14)
12 (15)
29
9
13
21 (22)
17
20
32 (29)
12 (15)
44
Data from areas and hosts out of the Antarctic are omitted. Numbers including immature
forms are in parentheses
K. Zdzitowiecki
present data, each is specific to one higher taxon of fishes, the first one to
the superfamily Notothenioidei, the second to the family Liparididae.
Other representatives of Monorchiidae and Fellodistomidae (not listed
here) were recorded in the SubAntarctic.
Data on the diversity of Digenea of fishes in different areas of the
Antarctic (Table 5) should be regarded as preliminary ones, as they are
strongly dependent upon the extent of research. For example, the smallest
number of digenean species (9) has been reported from the Ross Sea, but
almost all data are based on examinations of fishes caught in relatively
shallow waters (down to ca. 200 m) with the only exception being one
zoarcid species occurring at a depth of ca. 600 m. The greatest number of
species (22) has be-en-reported from the Weddell Sea, where a lot of deep
water fish species have been investigated, including many others than
Notothenioidei. More digenean species were recorded in the South Georgia
area than off the South Shetland Islands. It is clearly dependent upon the
research on muraenolepidids in the former area, as numbers of parasites of
Notothenioidei are similar in both areas. Data from the Indian sector of the
Southern Ocean are considerably less numerous than those from the
Weddell Sea. They are based mainly on material collected over 60 years
ago and elaborated 40 years later [9], with additional data based on a
limited number of fishes received by the present author from Russian,
Italian and French ichthyologists. Thus, a low number of parasite species
appears to be associated with too poor investigations. It should be noted
that intensities of digenean infections are greater in coastal zones
(especially in fjords) in the Western Antarctic, reaching to more than 1000
parasites in some Notothenia neglecta and N rossii, than in the open sea
and deep waters, especially in the Eastern Antarctic (normally several,
rarely more than ten parasites in one fish).
Table 5. Species diversity and specificity offish Digenea in different areas of the Antarctic
Area and specificity
Number of species
Parasitic in Notothenioidei
Parasitic in other fishes
Total
Ross Sea
Indian sector
Weddell Sea
South Shetlands
South Georgia
Specific parasites
Nonspecific parasites
Total
9
10
13 (14)
15
13 (15)
15
12 (15)
27 (30)
2
6
8
4
9
17 (14)
12 (15)
29
9
13
21 (22)
17
20
32 (29)
12 (15)
44
Data from areas and hosts out of the Antarctic are omitted. Numbers including immature
forms are in parentheses