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Similarities and differences in 13 C and 15 N stable isotope ratios in two non‐lethal tissue types from shovelnose sturgeon Scaphirhynchus platorynchus (Rafinesque, 1820)
Author(s) -
DeVries R. J.,
Schramm H. L.
Publication year - 2015
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12708
Subject(s) - biology , δ13c , δ15n , fish fin , anatomy , sturgeon , trophic level , stable isotope ratio , zoology , fish <actinopterygii> , fishery , ecology , physics , quantum mechanics
Summary We tested the hypothesis that δ 13 C and δ 15 N signatures of pectoral spines would provide measures of δ 13 C and δ 15 N similar to those obtained from fin clips for adult shovelnose sturgeon Scaphirhynchus platorynchus . Thirty‐two shovelnose sturgeon (fork length [FL] = 500–724 mm) were sampled from the lower Mississippi River, USA on 23 February 2013. Isotopic relationships between the two tissue types were analyzed using mixed model analysis of covariance. Tissue types differed significantly for both δ 13 C (P < 0.01; spine: mean = −23.83, SD = 0.62; fin clip: mean = −25.74, SD = 0.97) and δ 15 N (P = 0.01; spine: mean = 17.01, SD = 0.51; fin clip: mean = 17.19, SD = 0.62). Neither FL nor the FL × tissue type interaction had significant (P > 0.05) effects on δ 13 C. Fin clip δ 13 C values were highly variable and weakly correlated ( r = 0.16, P = 0.40) with those from pectoral spines. We found a significant FL‐tissue type interaction for δ 15 N, reflecting increasing δ 15 N with FL for spines and decreasing δ 15 N with FL for fin clips. These results indicate that spines are not a substitute for fin clip tissue for measuring δ 13 C and δ 15 N for shovelnose sturgeon in the lower Mississippi River, but the two tissues have different turnover rates they may provide complementary information for assessing trophic position at different time scales.