* Preservation Effects on Stable Isotope Analysis of Fish Muscle

Article in Transactions of the American Fisheries Society · March 2002

D. ALBREY ARRINGTON* AND KIRK O. WINEMILLER

• Transactions of the American Fisheries Society 131(2)
• DOI: 10.1577/1548-8659(2002)1312.0.CO;2

We evaluated the effect of salt and formalin-ethanol sample preservation on carbon and nitrogen isotopic signatures of fish muscle tissue. We found statistically significant effects of the tissue preservation technique on both δ13C and δ15N; however, the magnitude of change was small and directionally uniform. Isotopic shifts were similar to those observed in previous studies in which formalin was used to preserve samples of quail blood and muscle and sheep blood. Because salt preservation caused minimal isotopic shifts (+0.13‰ δ13C, +0.72‰ δ15N), we propose salt as an easy, inexpensive preservation technique for biological samples collected in remote field settings. Specimens preserved with formalin and ethanol were minimally affected by preservation (−1.12‰ δ13C, +0.62‰ δ15N) and therefore may be suitable for ecological applications of stable isotope analysis when carbon and nitrogen sources are differentiated by more than 2‰. Further research is required to evaluate potential long-term storage effects of formalin fixation and alcohol preservation on isotopic signatures of fish tissues.

I suggest in freezer at -20 °C as the simplest solution.

Freezing is ok, but if you just dry the tissues at temperature lower than 60C, the effect on stable isotope composition will be very small. typically much smaller than a normal within-species variation