Tissue-specific turnover rates and trophic enrichment of stable N and C isotopes in juvenile Atlantic cod Gadus morhua fed three different diets
A 150 d laboratory diet-shift study was conducted on juvenile Atlantic cod Gadus morhua L. to examine (1) stable nitrogen and carbon isotope turnover rates, (2) the tissue-specific relative contribution of metabolism and growth to isotopic change, and (3) diet-tissue enrichment of the isotopes in wh...
| Published in: | Marine Ecology Progress Series |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
2012
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| Subjects: | |
| Online Access: | https://pure.au.dk/portal/da/publications/tissuespecific-turnover-rates-and-trophic-enrichment-of-stable-n-and-c-isotopes-in-juvenile-atlantic-cod-gadus-morhua-fed-three-different-diets(860a72f4-96b8-449d-9108-395c532363a0).html https://doi.org/10.3354/meps09871 http://www.scopus.com/inward/record.url?scp=84864875675&partnerID=8YFLogxK |
| Summary: | A 150 d laboratory diet-shift study was conducted on juvenile Atlantic cod Gadus morhua L. to examine (1) stable nitrogen and carbon isotope turnover rates, (2) the tissue-specific relative contribution of metabolism and growth to isotopic change, and (3) diet-tissue enrichment of the isotopes in white muscle, heart, whole blood, and cranial bone collagen. Time- and growth-based models described the change in δ N and δ C of the tissues following a diet shift from pelleted food to either blue mussels Mytilus edulis L., sandeel Ammodytes marinus Raitt., or whiting Merlangius merlangus L. diets. Cod growth rates ranged from 1.5 to 2.0% d , with the exception of whiting-fed cod that experienced a cessation in growth after Day 86. Isotope turnover rates, expressed as half-lives (T ), differed little between tissues as expected in fast-growing fish. For δ N, heart tissue had the shortest T while muscle had the longest (30.7 to 34.8 versus 35.7 to 77.9 d range among diets). Heart tissue also had the shortest δ C T , whereas blood had the longest (25.5 to 38.5 versus 49.5 to 60.3 d range among diets). Diet-tissue enrichment varied between 0.8 and 5.1‰ (Δδ N) and between 0.7 and 2.2‰ (Δδ C). Growth accounted for most of the isotopic change, except in heart tissue of all cod and in all tissues of whiting-fed cod, where there was a significant effect of metabolism on isotopic change. Despite variability in enrichment among diets and tissues, fish feeding on the 3 diets could be distinguished based on their tissue-specific isotopic signatures. |
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