Stable isotope values in tissues of live and stranded dolphins and manatees from the northern Gulf of Mexico

Dataset extent

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The dataset includes stable carbon and nitrogen isotope ratios in tissues from bottlenose dolphins in coastal Alabama waters and manatees in the northern Gulf of Mexico, separated into two datasets: 1) Decomposition field study (workbook 1), which includes data from live sampled (skin) and dead stranded (liver, skin, and muscle) individuals relative to the decomposition stage of each individual. Isotope data from live dolphins were obtained using dart biopsy methods on dolphins within Mobile Bay. Isotope data from live manatees were obtained during health assessments and capture events in Alabama waters. Samples from live dolphins were from Mobile Bay, AL during 2019 and 2020. Samples from stranded dolphins were from 2011-2019 from coastal Alabama waters. Samples from live manatees were taken from animals between 2009-2017 and from stranded manatees between 2008-2017. This dataset contains the stable isotope values from live and dead stranded dolphins and manatees as well as the tissue sampled (liver, skin, muscle), the condition code specifying whether the sample was from a live or dead animal and, if dead, the decomposition code at time of sampling. This workbook also contains information on the year of sampling and the total amount of carbon and nitrogen in the sample. 2) Decomposition experiment (workbook 2), which includes stable carbon and nitrogen isotope values in liver, skin, and muscle of one dolphin and one manatee where the samples were left in natural conditions while being sampled for isotope values as they decomposed for 10 days. Subsamples were taken on days 0 (before any experimental decomposition), 1, 3, 6, and 10 to capture potential isotopic changes during decomposition. The dolphin and manatee stranded in coastal Alabama waters in 2019 (dolphin) and 2021 (manatee). This workbook contains stable carbon and nitrogen isotope values, total amount of carbon and nitrogen, tissue type, species, day sampled, and accumulated degree days (ADD), which is the sum of daily temperatures.


These data are part of a study to test the validity of using δ13 C and δ15 N values from tissues of stranded bottlenose dolphins (Tursiops truncatus) and West Indian manatees (Trichechus manatus) for ecological studies. Using a combination of quantifying overlap between stranded and live-captured animals, comparing isotope values from different stages of decomposition, and sampling tissues as they experimentally decomposed, we determined that isotope values between live and dead stranded overlapped in skin but there were greater effects of decomposition occurred in tissues that decompose more quickly, such as liver. Muscle was much less affected by decomposition across the time frame we examined. These effects occurred primarily in stable carbon isotopes and stable nitrogen was less affected. Our results on the decomposition effects on stable isotope values have important implications in the use and interpretation of stable isotopes from stranded individuals.

DOI: 10.57778/9xbe-kr37

Suggested Citation

Cloyed, C., Carmichael, R., Clance, L., & Bouveroux, T. (2022). Stable isotope values of live and stranded dolphins and manatees from the northern Gulf of Mexico [Data set]. Dauphin Island Sea Lab.

Related Publication Citation

Cloyed, C.S., Johnson, C., DaCosta, K.P., Clance, L.R., Russell, M.L., Díaz Clark, C., Hieb, E.E., Carmichael, R.H. (2023). Effects of tissue decomposition on stable isotope ratios and implications for use of stranded animals in research. Ecosphere

Data and Resources

Additional Info

Field Value
Author Carl Cloyed
Version 0.1
Last Updated November 30, 2022, 19:36 (UTC)
Created November 22, 2022, 22:02 (UTC)
Temporal Begin 2011
Temporal End 2020
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