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Severe thiamine deficiency in eastern Baltic cod (Gadus morhua)
Josefin Engelhardt1, Oscar Frisell1, Hanna Gustavsson1
1Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden.
Plos One
|January 3, 2020
Summary
Eastern Baltic cod exhibit widespread thiamine deficiency, impacting their health and potentially contributing to population decline. This deficiency is severe in many individuals, raising concerns for the species
Area of Science:
- Marine Biology
- Fish Physiology
- Ecology
Background:
- The eastern Baltic cod population has declined for over 30 years.
- Potential causes include overfishing, predation, low dissolved oxygen, and salinity changes.
- Thiamine deficiency has been observed in various Baltic Sea species.
Purpose of the Study:
- To investigate thiamine status in eastern Baltic cod.
- To determine if thiamine deficiency is a factor in population decline.
Main Methods:
- Chemical analysis of thiamine and its metabolites (SumT) in liver tissue using HPLC.
- Biochemical analysis of transketolase enzyme activity in liver and brain tissue.
- Correlation analysis between thiamine biomarkers and biological parameters (age, weight, otolith weight).
Main Results:
- 77% of cod showed liver thiamine deficiency; 13% had severe deficiency.
- 77% of cod showed brain thiamine deficiency; 64% had severe deficiency.
- Thiamine deficiency increased with age; heavier otoliths correlated with lower SumT.
- Only 2% of cod had a healthy condition factor; 49% indicated poor health.
Conclusions:
- Severe thiamine deficiency is prevalent in the eastern Baltic cod.
- This deficiency is a significant concern, especially in the sole remaining spawning area.
- Thiamine deficiency may be a key driver of the observed population decline.
