Cooperative Fish and Wildlife Research Units Program: Hawaii
Education, Research and Technical Assistance for Managing Our Natural Resources

Pease AA, JE Pease, PT Bean, & TB Grabowski. 2022. Endemic Guadalupe Bass (Micropterus treculii) are supported by isotopically distinct resources in tributary versus mainstem river food webs. River Research and Applications. doi: 10.1002/rra.4015


We used stable isotope analysis to investigate differences in Guadalupe bass Micropterus treculii resource use that might be associated with population-level variation in main-stem river versus tributary stream habitats. Micropterus treculii from main-stem sites had more enriched δ13C and δ15N signatures compared to those collected in tributaries, likely reflecting greater importance of algae as a basal resource and influences of urban wastewater in main-stem habitats. Documenting ecological variation across ecosystem types is important to inform fish conservation efforts, especially for species that occupy a range of stream sizes.