Abundance and distribution of Diphyllobothrium ditremum Creplin (Cestoda: Pseudophyllidea) plerocercoids in benthic whitefish, in northern Finnish Lapland

• Published in: Journal of Fish Biology
• Main Authors: Tolonen, A., Rita, H., Peltonen, H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2000
• Subjects: Kilpisjärvi; Lapland
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2000.tb00772.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2000.tb00772.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2000.tb00772.x

The prevalence of Diphyllobothrium ditremum plerocercoids in whitefish Coregonus lavaretus ranged between 70 and 100% in Lake Kilpisjärvi and in three other lakes in Northern Lapland, Finland. The mean abundance in Lake Kilpisjärvi (age groups 1+‐10+ years), ranged between 103·5± 71·3 in 1992–1993 to 110·9± 80·0 plerocercoids per fish in 1997. The asymptotic value of the infection levelled at 113 plerocercoids per host after age 3. No significant difference in abundance was detected between study years ( P >0·10). Abundances in other lakes ranged between 4·8±9·7 and 91·1±115·1. Two seasonal peaks of plerocercoid recruitment were observed in Lake Kilpisjärvi; between March and April ( P <0·002) and between September and October ( P =0·042). In autumn the numbers of larvae increased particularly in female fish. The invasion rate of the parasite was lower in other lakes studied, and the infection rate in whitefish was closely related to the copepod food eaten.