Abstract
An understanding of lifetime trophic changes and ontogenetic habitat shifts is essential to the preservation of marine fish species. We used carbon and nitrogen stable isotope values (δ 13 C and δ 15 N) recorded within the laminar structure of fish eye lenses, reflecting both diet and location over time, to compare the lifetime trends of 2 demersal mesopredators. Tilefish Lopholatilus chamaeleonticeps inhabit burrows on the outer continental shelf, which results in exceptional site fidelity. Red grouper Epinephelus morio are spawned on the middle to outer continental shelf, move to the inner shelf for the juvenile period, and return offshore upon sexual maturity. Both species inhabit the eastern Gulf of Mexico, a region with a distinctive offshore-inshore gradient in background δ 13 C values. Within individual tilefish (n = 36), sequences of δ 13 C values and δ 15 N values had strong, positive correlations with eye-lens diameter, and strong correlations between the 2 isotopes (mean Spearman r = 0.86), reflecting an increase in trophic position with growth and little lifetime movement. In red grouper (n = 30), δ 15 N values positively correlated with eye-lens diameter, but correlations between δ 15 N and δ 13 C were weak (mean Spearman r = 0.29), suggesting cross-shelf ontogenetic movements. Linear mixed model results indicated strong relationships between δ 15 N and δ 13 C values in tilefish eye lenses but no convergence in the red grouper model. Collectively, these results are consistent with previously established differences in the life histories of the 2 species, demonstrating the potential utility of eye-lens isotope records, particularly for investigating the life histories of lesser-known species.
Original language | American English |
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Journal | Marine Ecology Progress Series |
Volume | 657 |
DOIs | |
State | Published - Jan 1 2021 |
Keywords
- Stable isotopes
- Fish eye lenses
- Fish movement
- δ13C
- δ15N
- Trophic growth
Disciplines
- Life Sciences