Rapid 13C/12C turnover during growth of brown shrimp (Penaeus aztecus)
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Using natural-abundance 13C/12C ratios as tracers, carbon turnover rates were determined for postlarval brown shrimp, Penaeus aztecus, in five laboratory growth experiments. Although tissue turnover in adult animals generally occurs during maintenance metabolism and is a function of time, turnover for young postlarval shrimp was accelerated during growth, and was primarily a function of weight gained rather than time. Metabolic loss of tissue carbon during growth was usually approximated by the function, Fraction lost=1-(initial weight/final weight). For shrimp that switch diets in the sea, model calculations show that this high turnover rate coupled with a four-fold weight increase suffices for shrimp to achieve a close isotopic resemblance of 1‰ or less (δ13C units) to the new diet.
In accordance with these predictive calculations, shrimp which had increased in weight by a factor of four or more in the culture experiments showed essentially constant isotopic values reflecting their new diets. For these larger animals, the average animal-diet difference varied across three diets from-0.9 to +11‰, and the δ13C range among individuals was ≦1.4‰ in each experiment.
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- Craig H (1957) Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide. Geochim Cosmochim Acta 12:133–149Google Scholar
- Fry B (1981a) Natural stable carbon isotope, tag traces Texas shrimp migrations. Fish Bull 79:337–345Google Scholar
- Fry B (1981b) Tracing shrimp migrations and diets using natural variations in stable isotopes. PhD dissertation, Univ Tx, Austin. 225 ppGoogle Scholar
- Haines EB, Montague CL (1979) Food sources of estuarine invertebrates analyzed using 13C/12C ratios. Ecology 60:48–56Google Scholar
- McConnaughey T, McRoy CP (1979) 13C label identifies eelgrass (Zostera marina) carbon in an Alaskan esturine food web. Mar Biol 53:263–269Google Scholar
- Silvert W (1979) Practical curve fitting. Limnol Oceanogr 24:767–773Google Scholar
- Sofer Z (1980) Preparation of carbon dioxide for stable carbon isotope analysis of petroleum fractions. J Anal Chem 52:1389–1391Google Scholar
- Zein-Eldin ZP, Aldrich DV (1965) Growth and survival of postlarval Penaeus aztecus under controlled conditions of temperature and salinity. Fish Bull 129:199–216Google Scholar