Transgenerational marking of brown trout Salmo trutta f.f., using an ⁸⁴Sr spike

Abstract

The maternal transmission of a naturally occurring and non‐toxic minor isotope of strontium (84Sr) to the central otolith region of the progeny of a typical European freshwater fish species, brown trout, Salmo trutta f.f. L. was accomplished. The focus was to apply minimum doses of a non‐toxic solution at physiological salt concentration to minimise potential adverse effects on the fish. Female spawners were intraperitoneally injected with doses of 12.5 and 30.2 μg 84Sr kg−1 fish. Eggs were stripped and the resulting progeny were reared in a hatchery for about 1 year before sampling the otoliths. Strontium isotope ratios in the otoliths of the offspring were measured by cross‐sectional line scans using laser ablation‐multiple collector‐inductively coupled plasma mass spectrometry (LA‐MC‐ICPMS). Otolith cores of marked juveniles showed a significantly elevated 84Sr/86Sr ratio compared with control fish and to otolith regions created after hatching. Mass marking of cohorts of progeny from individually spiked brown trout with Sr isotopes is therefore possible for dispersal and migration studies without the necessity of handling eggs and applying other larval marking methods like immersion.

Application of non-traditional stable isotopes in analytical ecogeochemistry assessed by MC ICP-MS - A critical review

“…Since then, the method has been applied successfully and accepted as highly potential labeling tool for tracking of fish Important ecological questions like larval dispersal, homing of fish and the success of restoration measures by directly marking fish that migrate into those sections for spawning could be tackled [168,177]. Until today, above all, stable Sr spikes [154,178] and Ba isotopes [168] have been successfully used in this context.…”

Inductively Coupled Plasma Mass Spectrometry

“…For example, a stable Sr spike has been used for this purpose. 539,540 Alternatively, a barium dual-isotope spiking approach was developed, which allows for individual specific signatures for progenies of differently marked mother fish. 541 The issue of food authenticity, e.g.…”

Maternally transmitted isotopes and their effects on larval fish: a validation of dual isotopic marks within a meta-analysis context

“…Transgenerational marking is a new technique for massmarking the offspring of female fish; it involves injecting the maternal source with an enriched stable isotope of either barium or strontium (Thorrold et al 2006;Zitek et al 2013). The enriched stable isotope is transmitted into the egg and then incorporated into the otoliths of the developing larva.…”

“…Transgenerational marking has been successfully used in the wild to examine larval dispersal of clownfish and butterflyfish in coral reef ecosystems (Almany et al 2007). Multiple studies have also validated the efficacy of the technique as a marking tool while exploring the impacts of the technique on both the female fish injected (Williamson et al 2009b;Roy et al 2013) and the subsequent progeny produced (Williamson et al 2009a;Zitek et al 2013). These previous studies have attempted to elucidate whether minute quantities of enriched stable isotopes have toxic effects on larval size and growth (Williamson et al 2009a;Zitek et al 2013) or pose a threat to human health after consumption of injected fish (Williamson et al 2009b).…”