Table 1.
Mean (± SD) δ15N and δ13C (‰) measured in the plasma and red blood cells of male and female southern stingrays sampled in January, April, July, and October at Stingray City Sandbar. Sample sizes in parentheses.
| January | April | July | October | |||||
|---|---|---|---|---|---|---|---|---|
| Plasma | ||||||||
| δ15N Male | 11.4 ± 2.5 | (10) | 12.4 ± 0.1 | (2) | 12.6 ± 0.9 | (7) | 11.6 ± 1.1 | (7) |
| δ15N Female | 10.6 ± 1.7 | (10) | 11.4 ± 1.3 | (18) | 11.0 ± 1.5 | (18) | 9.7 ± 2.0 | (17) |
| δ13C Male | −17.3 ± 1.4 | (10) | −18.2 ± 0.1 | (2) | −17.0 ± 0.8 | (7) | −17.4 ± 1.0 | (7) |
| δ13C Female | −17.0 ± 1.2 | (10) | −17.2 ± 0.8 | (18) | −17.1 ± 0.7 | (18) | −16.7 ± 1.1 | (17) |
| Red blood cells | ||||||||
| δ15N Male | 11.7 ± 2.5 | (10) | 11.0 ± 0.3 | (2) | 12.9 ± 0.8 | (7) | 12.0 ± 0.9 | (7) |
| δ15N Female | 11.0 ± 1.7 | (10) | 11.9 ± 1.4 | (18) | 11.4 ± 1.5 | (18) | 10.3 ± 1.9 | (17) |
| δ13C Male | −16.1 ± 1.5 | (10) | −15.8 ± 0.2 | (2) | −16.7 ± 0.2 | (7) | −16.3 ± 0.4 | (7) |
| δ13C Female | −15.7 ± 0.9 | (10) | −16.5 ± 1.0 | (18) | −16.0 ± 0.7 | (18) | −16.3 ± 0.4 | (17) |