Strontium metabolism in the juvenile Lake Sturgeon, Acipenser fulvescens (Rafinesque, 1817), and further evaluation of the isotope as a marking tool for stock discrimination

Abstract

Stock enhancement efforts have been used to aid in increasing dwindling population levels of Lake Sturgeon, Acipenser fulvescens, that are currently of conservation concern. Consistent monitoring of stock enhanced fisheries requires a reliable and reproducible method to mark stocked fish such that the success of such programs can be determined. Recently, stable isotopic marking of hard structures in fish has been developed in a variety of species, however, optimal marking conditions are less well understood. In this study the metabolism of strontium in juvenile Lake Sturgeon and determined parameters for optimisation of marking success in the fin ray were examined. Using radioactive strontium ( 85 Sr), whole body influx and efflux rates of strontium were 3.02 AE 0.364 pmol h À1 g À1 (mean AE standard error) and 0.04 AE 0.007 pmol h À1 g À1 , respectively. Furthermore, short-term accumulation of 85 Sr in a variety of tissues was assessed and found to be greatest in the fin ray. Biological half-life of the stable isotope 86 Sr was shortest in muscle and longest in the fin ray tissue. Immersion and length of immersion timing had positive relationships with marking success. Additionally, the signature remained in 75% of fish analysed 550 days postmark. Data suggest that marking success was determined by duration of immersion in the mark and concentration of the mark introduced to the water.

Identification of Hatchery‐Reared Lake Sturgeon Using Natural Elemental Signatures and Elemental Marking of Fin Rays

“…These results are consistent with studies that have previously examined isotopic marking in sturgeon fin rays (Smith and Whitledge 2011a; Carriere et al. ; Mirali et al. ) in addition to otoliths in various teleosts (Ennevor and Beames ; Munro et al.…”

“…Conversely, Ba accumulation appeared to be relatively evenly distributed amongst muscle, vertebrae, and fin rays (Carriere et al. ; Loewen et al. ), perhaps due to the greater variation in Ba concentration, and ultimately demonstrated a trend opposite that reported for the fin rays of wild‐caught Lake Sturgeon from this study.…”

“…Indeed, Carriere et al. () observed Sr to be preferentially accumulated in the fin rays of age‐0 Lake Sturgeon. Conversely, Ba accumulation appeared to be relatively evenly distributed amongst muscle, vertebrae, and fin rays (Carriere et al.…”

“…The identification and manipulation of stable isotopic signatures in the fin rays of sturgeon species have been proven useful as a technique to batch‐mark hatchery‐reared individuals (Smith and Whitledge 2011a, 2011b; Carriere et al. ; Mirali et al. ).…”

“…() reported that the fin rays of juvenile Persian Sturgeon Acipenser persicus were successfully marked when the fish were immersed in 137 Ba for just 24 h. Despite the potential for resorption of fin ray material during periods of prolonged nutritional stress or spawning events, induced concentrations of 86 Sr remained detectable in the fin rays of sturgeon species 120–550 d after marking (Smith and Whitledge 2011a; Carriere et al. ), although the long‐term retention of elemental signatures (>2 years) in the fin rays of long‐lived species such as Lake Sturgeon A. fulvescens has yet to be ascertained.…”