Important sources of variation to be considered when using fin clips as surrogate for muscle in trophic studies using stable isotopes

GALVAN DE; FUNES M; LIBEROFF A; BOTTO F; IRIBARNE O

MARINE AND FRESHWATER RESEARCH

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2015 vol. 66 p. 730 - 738

1323-1650

White muscle is the prevalent tissue for C and N stable isotope analysis in fish, requiring the death of the fish or biopsy procedures that could led to infections or severe damage. Given that caudal fin-clipping does not seriously affect growth or condition, the present study assessed the suitability of caudal fin as muscle replacement in trophic studies. Caudal fin clips of caudal fin were a useful non-lethal surrogate of muscle samples in four studied reef-fish (Silver porgy, Diplodus argenteus,; Red porgy, Pagrus pagrus,; Argentinean sea bass, Acanthistius patachonicus and Brazilian sandperch Pinguipes brasilianus). Fin clips were easy to collect in quantities adequate to mass spectrometry analyses and had C:N ratios similar to white muscle with low lipid content. However, results showed that fin-muscle correction models should be specific and sampling should be conducted reducing spatial and temporal variation. Moreover, species-specific correction factors may not be valid to other populations of the same species if the presumably range of deltaX values differ from the population used to estimate the correction models.Thus, correction models could be applied for different populations and/or times only if deltaX values of the studied population presumably ranged within similar boundaries than the population used to estimate correction factors. Results also showed that fin-muscle relationship could vary with size. Thus, unless a non-ecological meaningful fin-muscle correlation with body size was previously identified, correction models should be estimated sampling a representative size range and fin samples should be used with caution to study size-related trophodynamic.