Líffræðifélag Íslands
Líffræðiráðstefnan 2015

Erindi/veggspjald / Talk/poster V49

Proliferative kidney disease (PKD) – the cause for declining stocks of arctic charr, Salvelinus alpinus, in iceland?

Fjóla Rut Svavarsdóttir (1)*, Þórólfur Antonsson (2), Mark Freeman (1,3) , Friðþjófur Árnason2, Árni Kristmundsson1

1. Tilraunastöð HÍ í meinafræði að Keldum, Keldnavegur 1-3, 112 Reykjavík, 2. Veiðmálastofnun, Árleyni 22, 112 Reykjavík, 3. Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.

Kynnir / Presenter: Fjóla Rut Svavarsdóttir

Tengiliður / Corresponding author: Fjóla Rut Svavarsdóttir (frs13@hi.is)

Proliferative kidney disease (PKD), a serious disease of salmonids caused by Tetracapsuloides bryosalmonae (T.b), was first identified in Iceland in 2008. The disease is temperature dependant and only emerges when water temperature exceeds 12-14°C for several weeks. Paralleled with increasing water temperature over the last decades, populations of Arctic charr have severely declined in many lowland lakes in Iceland. In 2008–2014, Arctic charr were regularly sampled from two lowland lakes in SW-Iceland experiencing severe declines in Arctic charr populations. Clinical signs of PKD were determined and kidney samples examined by histology and PCR. Furthermore, samples from fish caught in theses lakes in the 1990s were examined by PCR for the presence of T.b. The prevalence of T.b. was high in all years 2008-2014, irrespective of fish age. Clinical signs of PKD were also common in younger fish (<3 years) but varied between years of sampling. Similarly, T.b. infections were prevalent in Arctic charr in the lakes in the 1990s, but no data on clinical signs of PKD exist for those fish. T.b. existed in Icelandic freshwater in the 1990s and hence is not new in the ecosystem. In the early 1990s the first indications of the decline in Arctic charr became evident. At the same time the water temperature reached the critical level necessary for PKD to emerge. The results of this study indicate that PKD has played a significant role in the decline of populations of Arctic charr in Iceland.