Abstract
Stable isotopes recorded in fish eye lenses are an emerging tool to track dietary shifts coincident with use of diverse habitats over the lifetime of individuals. Eye lenses are metabolically inert, sequentially deposited, archival tissues that can open avenues to chronicle contaminant exposures, diet histories, trophic dynamics and migratory histories of individual fishes. In this study, we demonstrated that trophic histories reconstructed using eye lenses can resolve key uncertainties regarding diet and trophic habitat shifts. Clear Lake hitch (Lavinia exilicauda chi), a threatened cyprinid, inhabits a single lake (Clear Lake, Lake County, California) and utilizes tributary streams for reproduction. Bayesian mixing models applied to δ13C and δ15N recorded in eye lenses uncovered ontogenetic diet shifts that corresponded with shifts in occupation of habitats providing spawning (tributary streams), rearing (littoral lake), and growth (pelagic lake) functions. The reconstruction of size-structured trophic and habitat information can provide vital information needed to manage and conserve imperiled species such as the Clear Lake hitch.
Highlights
Many fish species utilize different habitats across ontogeny, including large-scale migrations across the landscape or smaller-scale movements into different local habitats
This study demonstrates the value of eye lenses for recreating diet-based migration histories, updates current understanding of Clear Lake hitch ecology, and highlights the importance of including multiple archival tissue types in reconstructing the life history of imperiled freshwater fishes
Fish collection summary Forty-six individual fish were retained from gill net sampling, ranging in size from 125 to 310 mm standard length
Summary
Many fish species utilize different habitats across ontogeny, including large-scale migrations across the landscape (e.g., ocean basin migrations, Block et al 2001; anadromy, Clemens et al 2010) or smaller-scale movements into different local habitats (e.g., marine vertical migration, Hawes et al 2020; offshore migrations in lakes, Maciej Gliwicz et al 2006). Traditional sampling techniques are hampered by inefficiency and spatiotemporal uncertainty, and physical tagging and (or) tracking methods can be logistically prohibitive or impossible. To get around these limitations, tissues that act as chemical archives have been increasingly utilized to reconstruct the life histories of individual fishes (Secor et al 1995; Tzadik et al 2017). During tissue formation and deposition these tissues uptake environmental constituents and are subsequently metabolically inert, meaning that there is no further resorption or chemical alteration of the tissue These tissues act as faithful recorders of environmental conditions at the time of tissue formation. Eye lenses are a metabolically inert, proteinaceous tissue type that has been successfully used to reconstruct biochemical data for individual fishes (Wallace et al 2014; Quaeck-Davies et al 2018; Bell-Tilcock et al 2021) and cephalopods (Parry 2003; Hunsicker et al 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
