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 Curtis1, Jennifer Granneman1, Benjamin Kurth1,

Timothy Pusack1, Amy Wallace1, David Hollander1, Ernst Peebles1,

Christopher Stallings1

1University of South Florida: College of Marine Science, St Petersburg, FL, USA

*Email: otzadik@mail.usf.edu 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