Thiamine concentrations in the Baltic Sea pelagic food web decrease with increasing trophic level
(English)Manuscript (preprint) (Other academic)
Thiamine deficiency in top predators has been reported from several aquatic systems. In the Baltic populations of the Atlantic salmon (Salmo salar) this has been observed since 1974, but knowledge of thiamine levels in its prey species is limited. To address this, we measured thiamine concentrations in different tissues of the major Baltic planktivores, Baltic herring (Clupea harengus membras) and Baltic sprat (Sprattus sprattus balticus). Additionally, we measured thiamine concentrations in the major pelagic top predator fish in the Baltic Sea, the Atlantic cod (Gadus morhua) and its prey species along with sprat and herring, the benthic isopod Saduria entomon. Field sampling was conducted during five offshore expeditions in the Baltic Sea proper in 2004, 2005 and 2010. Thiamine was analysed in liver, gonad, stomach and muscle tissues of the fish and the whole body of the isopod. Liver generally had the highest concentrations and muscle tissue the lowest. In contrast to previous reports from other aquatic ecosystems, there was a negative relationship between trophic level and thiamine in the Baltic Sea. Temporal fluctuations of thiamine concentrations in the fish showed the same pattern as previously shown for Baltic plankton communities. Altogether these results suggest a bottom up effect on the thiamine status of the higher trophic levels in the Baltic Sea, possibly influencing the occurrence of thiamine deficiency in Baltic top predators.
IdentifiersURN: urn:nbn:se:su:diva-89154OAI: oai:DiVA.org:su-89154DiVA: diva2:616049