Traditional techniques for stable isotope analysis (SIA) generally require sacrificing animals to collect tissue samples; this can be problematic when studying diets of endangered species such as the pallid sturgeon Scaphirhynchus albus. Our objectives were to (i) determine if pectoral fin tissue (non-lethal) could be a substitute for muscle tissue (lethal) in SIA of juvenile pallid sturgeon, and (ii) evaluate the influence of preservation techniques on stable isotope values. In the laboratory, individual juvenile pallid sturgeon were held for up to 186 day and fed chironomids, fish, or a commercially available pellet diet. Significant, positive relationships (r2 ??? 0.8) were observed between fin and muscle tissues for both ??15N and ??13C; in all samples isotopes were enriched in fins compared to muscle tissue. Chironomid and fish based diets of juvenile pallid sturgeon were distinguishable for fast growing fish (0.3 mm day-1) using stable ??15N and ??13C isotopes. Frozen and preserved fin tissue ??15N isotopes were strongly related (r2 = 0.89) but ??13C isotopes were weakly related (r2 = 0.16). Therefore, freezing is recommended for preservation of fin clips to avoid the confounding effect of enrichment by ethanol. This study demonstrates the utility of a non-lethal technique to assess time integrated food habits of juvenile pallid sturgeon and should be applicable to other threatened or endangered species. ?? 2010 Blackwell Verlag, Berlin.
Additional publication details
Application of non-lethal stable isotope analysis to assess feeding patterns of juvenile pallid sturgeon Scaphirhynchus albus: A comparison of tissue types and sample preservation methods