Download or read book Trophic Dynamics and Movements of Tuna in the Tropical Pacific Ocean Inferred from Stable Isotope Analyses written by Brittany Syra Graham and published by . This book was released on 2008 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Delta15N and delta13C values of animals can be used as natural tags to trace their movements through ecosystems. This method to studying animal movements requires isotopic variation at the base of the food web. Baseline delta15N values show strong geographical patterns in the eqPac. If tuna migrated extensively within these isotope gradients, little isotopic variation would be observed in tuna because baseline delta15N values would be integrated. Delta15N values of yellowfin, bigeye, and skipjack tuna showed ca. 12 0/00 variation, but spatially coherent structure in the eqPac. CSIA results revealed that this delta15N variation relates more to tuna movements than differences in their TL. Thus, the high isotopic variation observed in tuna reflects their restricted movements in the EqPac and differences between the species indicate different movement rates. In summary, this study established that isotope values of tunas are indicators of their foraging behavior, habitat utilization, and movements.