Hello there Oscar Juvall - a master student at the Institute of Freshwater Research who is currently investigating vitamin deficiency in salmon.
Can you tell us more about vitamin deficiency in salmon and your research?
Absolutely, but before we get into the details, it might be good to mention some brief background to my choice of topic. Today we know that Baltic salmon suffer from thiamine (vitamin B1) deficiency. The vitamin deficiency causes very high mortality in salmon offspring.
What role does vitamin B1 play in salmon?
It is essential for the development of the nervous system and various organs in salmon. However, salmon cannot produce thiamine on their own, they must get it from their food. For example, hatcheries releasing compensated salmon around Scandinavia usually bathe the salmon roe and fry in a vitamin solution to counteract vitamin deficiency and high mortality.
Vitamin deficiency in salmon is quite a complex topic that has been tackled by several different research groups and with different results - what are your thoughts on this?
Yes, the subject is incredibly complex and there are different research groups with different theories about the causes behind the deficiency. Today, there is a lot of concern about salmon health because salmon is such a valuable fish for many ecosystems, but also economically and traditionally.
What's your main focus in your research?
I am investigating the cause of vitamin deficiency in various species in the Baltic Sea, including salmon. The cause of the vitamin deficiency is most likely due to several different factors, where the salmon's diet probably plays a major role.
You've recently started an experiment with 40 different aquariums at the Institute of Freshwater Research at Drottningholm, tell us more about it?
Yes, right now we have 40 aquariums divided into five climate chambers, with 8 aquariums in each room. The chambers contain the Baltic Sea alga Ceramium teunicorne, which is a common alga in the Baltic Sea, and the water in these chambers will mimic the Baltic Sea water in salinity and nutrition. The idea is to simulate global warming, by changing salinity, light exposure and temperature, and then see if this affects the algae's ability to produce thiamine. These algae are the primary producers of thiamine in the food web and are therefore very important in the nutrient balance of ecosystems. An important part of this is to investigate thiamine production in algae to understand how they affect organisms higher up in the food web. If the production of thiamine decreases or fails, it could be a cause of the thiamine deficiency we see in salmon and possibly also many other aquatic species.
You also plan to study salmon fry at SLU's Fisheries Research Station in Älvkarleby, what exactly will you be looking at?
The plan is that I will hatch my own salmon fry from wild Dalälven salmon in Älvkarleby. Then I will study how the thiamine content in the roe reflects the development and survival rate of the fry. I do this to get a picture of how high percentage mortality occurs in the current recruitment of Dalälven salmon. I will also investigate the thiamine content in wild as well as farmed salmon to see how the thiamine levels differ.
What is most challenging in your work?
It's the lack of clarity about what actually causes vitamin deficiency. What we do know is that there are many different factors that affect our beloved salmon. The challenge is to understand these different perspectives and their impact on salmon survival.
Finally, what is the most enjoyable part of your research?
It's being part of the whole research group. I have been so incredibly well and warmly welcomed into the group, so that has definitely been the most fun for me. Otherwise, it has been fun to go out and collect algae samples, but also to accompany my colleague Manne out and collect his blue mussel samples from a mussel farm.