The use of stable isotope ratios of carbon and nitrogen to elucidate pelagic marine foodwebs of the Benguela and Agulhas Bank regions of South Africa

• Main Author: Sholto-Douglas, A D
• Other Authors: Field, John G
• Format: Dissertation
• Language: English
• Published: University of Cape Town 2016
• Subjects: zoology
• Online Access: http://hdl.handle.net/11427/17370

Bibliography: pages 75-84. === Isotope assessments of foodweb relationships amongst pelagic organisms may be influenced by their lipid content, since lipids are more depleted in ¹³C than other biochemical compounds. This is particularly important for plankton which show a greater decrease in δ¹³C caused by the failure to remove lipids during sample preparation, than the muscle tissue of pelagic fish species. Lipid removal is important for those fish species whose lipid content and magnitude of diet-consumer fractionation are simultaneously related to their size. The period required for pelagic fish to isotopically reflect a new diet is slow, of the order of months and years, and may depend on the diet and the magnitude of isotopic change displayed. It is likely that this rate decreases as the fish approach isotopic equilibrium with the new food source.