Element composition of shark vertebrae shows promise as a natural tag

Abstract

Reconstructing movements and environmental histories of sharks may be possible by using the element composition of vertebrae, but unlocking such possibilities requires an understanding of the effects of extrinsic and intrinsic factors on element composition. We assessed water temperature and pH effects (independently and in combination) on vertebral chemistry of Port Jackson sharks while accounting for intrinsic factors (condition and sex) using indoor aquaria and outdoor mesocosm environments, where the latter may better reflect natural field conditions. We analysed eight element:Ca ratios (7Li, 8B, 24Mg, 55Mn, 65Cu, 88Sr, 138Ba and 238U) by laser ablation inductively coupled plasma mass spectrometry and found positive temperature-dependant responses for multiple elements, including B:Ca, Mn:Ca, Sr:Ca and Ba:Ca (r2=0.43, 0.22, 0.60 and 0.35 respectively), whereas pH had a minor effect on vertebral Mg:Ca and Li:Ca (r2=0.10 and 0.31 respectively). As shown for teleost otoliths, condition affected element composition (Mn:Ca), suggesting potential physiological influences on element uptake. The suitability of vertebral chemistry as a natural tag appears to be element specific, and likely governed by a suite of potentially codependent extrinsic and intrinsic factors. Overall, variations in vertebrae chemistry show promise to reconstruct movements and habitat use of cartilaginous fishes. Yet, further research is required to understand the ubiquitous nature of the findings presented here.

Elasmobranch Responses to Experimental Warming, Acidification, and Oxygen Loss—A Meta-Analysis

“…Excluded were studies (or individual responses) that (i) lacked a suitable control treatment, TABLE 1 | Summary of the references including in the analysis across the different treatments, namely experimental warming (EW), acidification (EA), deoxygenation (ED), and their combination (EWA and EWD). Neale et al, 1977;Du Preez et al, 1988;Fangue and Bennett, 2003;Tullis and Baillie, 2005;Mull et al, 2008;Rodda and Seymour, 2008;Dabruzzi et al, 2013;Rosa et al, 2014Rosa et al, , 2016aDi Santo, 2015, 2016Pistevos et al, 2015;Johnson et al, 2016;Whitney et al, 2016;Lear et al, 2017;Pistevos et al, 2017Pistevos et al, , 2019Luongo and Lowe, 2018;Pouca et al, 2018Pouca et al, , 2019Di Santo, 2019;Hume, 2019;Schwieterman et al, 2019;Bouyoucos et al, 2020a,c;Crear et al, 2020;Musa et al, 2020;Pegado et al, 2020b;Gervais et al, 2021;Wheeler et al, 2021 EA Green andJutfelt, 2014;Heinrich et al, 2014Heinrich et al, , 2016Rosa et al, 2014Rosa et al, , 2016aDi Santo, 2015, 2016Dixson et al, 2015;Pistevos et al, 2015Pistevos et al, , 2017…”

Acid-base adjustments and first evidence of denticle corrosion caused by ocean acidification conditions in a demersal shark species

“…The potential impact of hypercapnia on mineralisation in elasmobranchs has been less studied so far: Chronic hypercapnia has an impact on the skeleton of juvenile (i.e. developing) skates 31 and a minor effect on mineralisation of vertebrae of juvenile sharks 32 . When the impact of hypercapnia on chondrichthyan denticles was investigated, no effects were found in juvenile catshark 21 (4–6 months at 1100 µatm) and skate embryos 31 (1 month at 990 µatm).…”

Sawfish, Read in Tooth and Saw: rostral teeth as endogenous chemical records of movement and life-history in a critically endangered species

“…The Mg/Ca ratio has been called the ‘chemical clock’ in some fish species due to its association with seasonal growth rates, and one controlled elasmobranch study has found limited evidence that Mg incorporation increases with condition (Limburg et al, 2018; Pistevos et al, 2019). Without additional information about sawfish in particular it is impossible to determine, but the repeated sharp peaks in this tracer are suggestive of periods of higher and lower growth (figure 3D), a relationship which merits further study.…”