Table 1.
Mean δ15N, δ13C, and C:N ratio values of California yellowtail (Seriola dorsalis) muscle tissue, captive feed, and calculated diet-specific DTDF values for pellet and fish/squid diet.
| Group | Isotope | Tissue | n | Mean (SD) | C:N (SD) (mass) | |||
|---|---|---|---|---|---|---|---|---|
| Feed | ||||||||
| Pellets | δ13C | – | 10 | − 22.6 (0.4) | 7.0 (0.5) | |||
| δ15N | – | 10 | 5.8 (0.1) | 7.0 (0.5) | ||||
| Mackerel | δ13C | WM | 6 | − 19.7 (0.1) | 3.2 (0) | |||
| δ15N | WM | 6 | 13.5 (0.1) | 3.2 (0) | ||||
| Squid | δ13C | WM | 6 | − 17.9 (0.5) | 3.4 (0) | |||
| δ15N | WM | 6 | 14.7 (0.3) | 3.4 (0) | ||||
| Fish/squid mean | δ13C | WM | 12 | − 19.0 (0.9) | – | |||
| Weighted by mass | δ15N | WM | 12 | 14.0 (0.8) | – | |||
| Yellowtail | DTDF | |||||||
|---|---|---|---|---|---|---|---|---|
| Mean | SD | Time in capt | ||||||
| Dietlow | δ15N | WM | 21 | 10.9 (0.3) | 3.6 (0.3) | 5.1 | 0.3 | 525 d |
| Dietlow* | δ13C | WM | 21 | − 19.0 (0.1) | 3.6 (0.3) | 3.6* | 0.1 | 525 d |
| Diethigh | δ15N | WM | 10 | 16.5 (0.2) | 3.4 (0.2) | 2.6 | 0.2 | > 595 d |
| Diethigh | δ13C | WM | 10 | − 17.7 (0.4) | 3.4 (0.2) | 1.3 | 0.4 | > 595 d |
δ13C values are arithmetically lipid-corrected according to Logan et al.55.
*The δ13C values of Dietlow (pellet diet) could not be corrected for carbonate and or lipid due to unknown pellet composition; this DTDF is based on bulk pellet δ13C values.