Imbalance of fatty acids in the base of the Baltic Sea food web a mesocosm study
A reproductive disturbance in Baltic Sea Atlantic salmon (Salmo salar), the M74 syndrome, has been reported since early 1970s and has occasionally caused up to 90% mortality for newborn fry. Previous research has revealed that the M74 syndrome may be due to reduced levels of the vitamin thiamin, the...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Canadian Science Publishing
2005
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Subjects: | |
Online Access: | http://dx.doi.org/10.1139/f05-140 http://www.nrcresearchpress.com/doi/pdf/10.1139/f05-140 |
Summary: | A reproductive disturbance in Baltic Sea Atlantic salmon (Salmo salar), the M74 syndrome, has been reported since early 1970s and has occasionally caused up to 90% mortality for newborn fry. Previous research has revealed that the M74 syndrome may be due to reduced levels of the vitamin thiamin, the carotenoid astaxanthin, and elevated ratios of ω3/ω6 fatty acids in salmon eggs. Using mesocosm experiments, we compared the quantity (µg·L 1 ) and quality (mg·g 1 C) of fatty acids in microalgae and copepods in the southern Baltic Sea where the M74 syndrome is common with those in a habitat in the Norwegian Sea where the syndrome has not been observed. Daily additions were made of the nutrients N and P or N, P, and Si, copepods were added after 67 days, and nutrient additions were stopped after 910 days. Flagellates dominated completely in the Baltic Sea, whereas higher phytoplankton diversity was found in the Norwegian Sea. We found elevated ω3/ω6 ratios in phytoplankton and abnormally high docosahexaenoic acid/arachidonic acid ratios (22:6ω3/20:4ω6) in copepods in the Baltic Sea mesocosms compared with those in the Norwegian Sea. Our results suggest that imbalance in fatty acid composition may prevail in the basic food web of the Baltic Sea. |
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