Chemical archives in fishes beyond otoliths: A review on the use of other body parts as chronological recorders of chemical constituents Orian Tzadik* 1 , Joseph Curtis 1 , Jennifer Granneman 1 , Benjamin Kurth 1 , Timothy Pusack 1 , Amy Wallace 1 , David Hollander 1 , Ernst Peebles 1 , Christopher Stallings 1 1 University of South Florida: College of Marine Science, St Petersburg, FL, USA *Email: [email protected] H:549 The Use of Alternative Structures Fin Spines (30 – 35% calcified) Fin Rays (23 – 29% calcified) Endoskeleton (up to 40% calcified) Scales (< 20% calcified) Eye Lenses (0% calcified) Advantages • Useful for aging studies Limitations • Lethal sampling required • TEA not recommended due to bone remodeling • SIA not recommended due to unknown isotopic turnover rates of bone collagen Advantages • Non-lethal sampling possible • Movement studies possible via TEA Limitations • Useful for aging studies, but possible loss of early annuli due to vascularization and resorption • Diet studies via SIA remain untested Advantages • Non-lethal sampling possible • Movement studies possible via both TEA and SIA • Diet studies possible via both TEA and SIA Limitations • Useful for aging studies, but possible loss of early annuli due to vascularization and resorption Advantages • Non-lethal sampling possible and samples are plentiful • Movement studies possible via both TEA and SIA • Diet studies possible via both TEA and SIA Limitations • Aging, movement, and diet studies are biased by edge crowding, metabolic reworking, over-plating, and inconsistent circuli formation Advantages • Movement studies possible via both TEA and SIA • Diet studies possible via both TEA and SIA • Easy workup with no expensive machinery required Limitations • Lethal sampling required • Has yet to be tested for suitability for aging studies • Completely un-calcified structure • Otoliths have been used in fisheries studies for 100+ years • Otoliths require lethal sampling, and lack a robust organic matrix for chronological Stable Isotope Analyses (SIA) • SIA and Trace Element Analyses (TEA) measure microchemical constituents of the organic and inorganic material in sequentially deposited tissues for movement and diet studies. • By reviewing the literature, we summarized the advantages and limitations of several alternative structures to otoliths for microchemical analyses