PhD defence: Tone Jøran Oredalen

Tone Jøran Oredalen disputerer. Breddebilde av henne.

Tone Jøran Oredalen will be defending her thesis for the degree of philosophiae doctor (PhD)

19 Aug

Practical information

  • Date: 19 August 2022
  • Time: 10.00 - 15.00
  • Location: Bø, Rom 4-311A and Zoom
  • Download calendar file

    • Follow the link to participate digitally in Zoom

    Program

    Kl. 10.00-11.00: Trial lecture, Room  4-311A and Zoom
    Trial lecture topic : «The potential use of eDNA in future studies on fish pathogens – flaws and advantages.»

    Kl. 12.30-14.30: PhD defence,  Room  4-311A and Zoom

    The title of the dissertation is: «Occurrence of Tetracapsuloides bryosalmonae in five large, dimictic lakes».

    Adjudication committee:

    • First opponent:
      Head of department Arní Kristmundsson, PhD, University of Iceland
    • Second opponent:
      Professor Audun Slettan, Universitety of Agder
    • Third opponent:
      Associate professor Helga Veronica Tinnesand, University of South-Eastern Norway

    Chair:

    • Professor Andrew Jenkins , University of South-Eastern Norway

    Supervisors:

    • Senior research scientist Tor Atle Mo, NIVA
    • Associate professor Mona Sæbø, University of South-Eastern Norway
Any questions?

Tone Jøran Oredalen will defend her dissertation for the degree of philosophia doctor (PhD) in Ecology at USN.

The dissertions title: «Occurrence of Tetracapsuloides bryosalmonae in five large, dimictic lakes».

Follow the link to participate digitally in Zoom

About the dissertation:

The PhD thesis has focused on the climate-related and emerging parasite Tetracapsuloides bryosalmonae, a potential harmful parasite for salmonids. Bottom-living freshwater bryozoans are the main host for completing the parasite life cycle. Infection with the parasite may lead to the potential lethal Proliferative Kidney Disease (PKD) in salmonids when water temperature exceeds 12-15° C for a period of more than 14 days.


Since the 1970`s, PKD has periodically caused high morbidity and mortality in both farmed and wild salmonids as rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), Atlantic salmon (Salmo salar) and Arctic charr (Salvelinus alpinus) in Europe and North America.


The parasite was detected by PCR analyses in kidney samples from salmonids and by lake water (using eDNA) from five large, deep Norwegian lakes, i.e. Lake Fyresvatn, Lake Totak, Lake Møsvatn, Lake Tinnsjå and Lake Norsjø. Most studies of salmonids infected by this parasite have so far been conducted in shallow lakes and rivers, but this work has also documented the PKD-parasite in Arctic charr and brown trout in large, deep Norwegian lakes, a common lake type in Norwegian nature. For the first time, the parasite was also documented in European whitefish (Coregonus lavaretus) in Norway.


As, so far, no vaccine against PKD exists, important countermeasures have been to expose the fish to lower water temperature to limit the temperature-dependent development of the disease, or to reduce the presence of the bottom-living freshwater bryozoans.  The cold, deep water of large Norwegian lakes will likely become increasingly important for our cold-water adapted salmonids in an expected warmer climate, and these cold habitats may contribute to reduced development of lethal PKD in fish infected by T. bryosalmonae.