Open AccessUsing hydrogen isotopes of freshwater fish tissue as a tracer of provenance
Author(s) -
Soto David X.,
Hobson Keith A.,
Wassenaar Leonard I.
Publication year - 2016
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.2519
Subject(s) - trophic level , environmental chemistry , bioconcentration , isotope , chemistry , freshwater fish , fish <actinopterygii> , ecology , biology , bioaccumulation , fishery , physics , quantum mechanics
Hydrogen isotope (δ 2 H) measurements of consumer tissues in aquatic food webs are useful tracers of diet and provenance and may be combined with δ 13 C and δ 15 N analyses to evaluate complex trophic relationships in aquatic systems. However, δ 2 H measurements of organic tissues are complicated by analytical issues (e.g., H exchangeability, lack of matrix‐equivalent calibration standards, and lipid effects) and physiological mechanisms, such as H isotopic exchange with ambient water during protein synthesis and the influence of metabolic water. In this study, δ 2 H (and δ 15 N) values were obtained from fish muscle samples from Lake Winnipeg, Canada, 2007–2010, and were assessed for the effects of species, feeding habits, and ambient water δ 2 H values. After lipid removal, we used comparative equilibration to calibrate muscle δ 2 H values to nonexchangeable δ 2 H equivalents and controlled for H isotopic exchange between sample and laboratory ambient water vapor. We then examined the data for evidence of trophic δ 2 H enrichment by comparing δ 2 H values with δ 15 N values. Our results showed a significant logarithmic correlation between fork length and δ 2 H values, and no strong relationships between δ 15 N and δ 2 H. This suggests the so‐called apparent trophic compounding effect and the influence of metabolic water into tissue H were the potential mechanisms for δ 2 H enrichment. We evaluated the importance of water in controlling δ 2 H values of fish tissues and, consequently, the potential of H isotopes as a tracer of provenance by taking account of confounding variables such as body size and trophic effects. The δ 2 H values of fish appear to be a good tracer for tracking provenance, and we present a protocol for the use of H isotopes in aquatic ecosystems, which should be applicable to a broad range of marine and freshwater fish species. We advise assessing size effects or working with fish of relatively similar mass when inferring fish movements using δ 2 H measurements.