48
CARL J. SINDERMANN
of sockeye salmon primarily as an aid in identifying the continental
origin of high seas stocks. Margolis (1963), who summarized these
studies, reported that certain parasites were peculiar to Asian stocks
and others to North American. Over 50 species of parasites were
encountered in the survey, many of which varied locally or seasonally,
and some of which occurred throughout the range of the host species,
although in different frequencies. A larval cestode, Triaenophorus
crassus Forel, was found in the flesh of salmon from Bristol Bay, but
was absent from Kamchatkan samples. Conversely, an adult nematode,
Cucullanus truttae (Fabr.), was found in Kamchatka and Okhotsk Sea
samples, but was absent from North American samples.
Highly localized variations in abundance of disease were seen in
myxosporidean (Kudoa clupeidae) infection of Atlantic herring in the
Gulf of Maine. A sharp discontiiiuity existed on the Maine coast,
documented for ten years (Sindermann, 1965), in which l-year-old
fish were commonly found to be infected on the western coast and
were never found to be infected on the eastern coast. This difference
has been attributed largely to summer sea water temperatures, although
other factors may be involved. The discontinuity wa5 so distinct that
cysts of the parasite have been used as natural tags to trace subsequent movements of immature fish. The gall-bladder-inhabiting
Myxosporidea of whiting have been found to vary in abundance
geographically in the North Sea (Kabata, 1963b). Ceratomyxa arcuata
Thdohan occurred in 46% of whiting sampled in the northern North
Sea: while Myxidium sphaericum Thdlohan infection was only 1.3%.
The reverse was found in the southern North Sea, with Myxidium
reaching an average of 40% while Ceratomyxa averaged only 9%. This
suggested the existence of two North Sea whiting stocks-a conclusion
siipported by meristic data.
Broader geographic variations in parasite frequencies were disclosed
in a study of the distribution of larval cestodes (Trypanorhyncha) in
adult herring from the north-west Atlantic. The parasites were absent
in four years' sampling from the Gulf of Saint Lawrence, but increased
in frequency with decreasing latitude (Fig. 14). A strikingly similar
situation prevails in the Pacific. Dogie1 (1955) observed that mintai
or Alaska pollock, Theragra chalcogramma, which are heavily parasitized by larval cestodes from sharks, harbored far fewer worms in
Kamchatkan waters than in Japanese waters. Variations such as these
are undoubtedly related to distribution and abundance of the elasmobranch definitive hosts.
Differences of a comparable geographic scale were reported for two
coccidians, Eimeria sardinae and E. clupearum, in herring. Polyanski
CARL J. SINDERMANN
of sockeye salmon primarily as an aid in identifying the continental
origin of high seas stocks. Margolis (1963), who summarized these
studies, reported that certain parasites were peculiar to Asian stocks
and others to North American. Over 50 species of parasites were
encountered in the survey, many of which varied locally or seasonally,
and some of which occurred throughout the range of the host species,
although in different frequencies. A larval cestode, Triaenophorus
crassus Forel, was found in the flesh of salmon from Bristol Bay, but
was absent from Kamchatkan samples. Conversely, an adult nematode,
Cucullanus truttae (Fabr.), was found in Kamchatka and Okhotsk Sea
samples, but was absent from North American samples.
Highly localized variations in abundance of disease were seen in
myxosporidean (Kudoa clupeidae) infection of Atlantic herring in the
Gulf of Maine. A sharp discontiiiuity existed on the Maine coast,
documented for ten years (Sindermann, 1965), in which l-year-old
fish were commonly found to be infected on the western coast and
were never found to be infected on the eastern coast. This difference
has been attributed largely to summer sea water temperatures, although
other factors may be involved. The discontinuity wa5 so distinct that
cysts of the parasite have been used as natural tags to trace subsequent movements of immature fish. The gall-bladder-inhabiting
Myxosporidea of whiting have been found to vary in abundance
geographically in the North Sea (Kabata, 1963b). Ceratomyxa arcuata
Thdohan occurred in 46% of whiting sampled in the northern North
Sea: while Myxidium sphaericum Thdlohan infection was only 1.3%.
The reverse was found in the southern North Sea, with Myxidium
reaching an average of 40% while Ceratomyxa averaged only 9%. This
suggested the existence of two North Sea whiting stocks-a conclusion
siipported by meristic data.
Broader geographic variations in parasite frequencies were disclosed
in a study of the distribution of larval cestodes (Trypanorhyncha) in
adult herring from the north-west Atlantic. The parasites were absent
in four years' sampling from the Gulf of Saint Lawrence, but increased
in frequency with decreasing latitude (Fig. 14). A strikingly similar
situation prevails in the Pacific. Dogie1 (1955) observed that mintai
or Alaska pollock, Theragra chalcogramma, which are heavily parasitized by larval cestodes from sharks, harbored far fewer worms in
Kamchatkan waters than in Japanese waters. Variations such as these
are undoubtedly related to distribution and abundance of the elasmobranch definitive hosts.
Differences of a comparable geographic scale were reported for two
coccidians, Eimeria sardinae and E. clupearum, in herring. Polyanski