Resumen del producto

Researches using stable isotopes analysis (SIA) of carbon (d13C) and nitrogen (d15N) in blood components (red blood cells and plasma) are still lacking, considering the challenge of sample collection in remote areas. There is poor information regarding the effect of tissue biochemical composition on isotopic ratios and there are few comparisons among different taxa in this regard. We explore the possibility that tissues biochemistry of different taxa affect isotopic results. During 2016 and 2017 we collected blood samples from shortfin mako sharks (Isurus oxyrinchus, n=70) and Guadalupe fur seals (Arctocephalus philippii townsendi, n=25). All the samples were centrifuged to obtain plasma in the case of mako sharks and serum for fur seals and then prepared for SIA. We did not find statistical differences d15N values, but we found significant differences comparing d13C in plasma of mako sharks (d13C= -17.6 ± 0.9 ‰) and in serum of fur seals (d13C= -20.3 ± 1.2‰). Furthermore, we tested the possible effect of different anticoagulants for sharks and lipids effect for Guadalupe fur seal samples. We did not find differences between both tests. The lack of significant d15N differences between the Guadalupe fur seal and the shortfin mako shark likely is due to these two species feeding at similar trophic levels. The d13C differences between both species are probably due to serum and plasma biochemical characteristics, like lipid percentage in each species, more than differences in foraging area. These biochemistry characteristics in tissues are related to different adaptations within each taxa. This study shows the importance of developing more research on the influence of biochemistry features on isotopic results, because that blood component biochemistry may play a more important role in influencing isotopic signature than differences in foraging area.

Palabras clave: Isurus oxyrinchus; Arctocephalus philippii townsendi; isotopic variation

Para obtener una copia del documento contacta la personal de la biblioteca a través del correo bibliocicimar{a}ipn.mx