Transgenerational marking of embryonic otoliths in marine fishes using barium stable isotopes

• Published in: Canadian journal of fisheries and aquatic sciences 2006-06, Vol.63 (6), p.1193-1197
• Main Authors: Thorrold, Simon R, Jones, Geoffrey P, Planes, Serge, Hare, Jonathan A
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Amphiprion melanopus; Animal, plant and microbial ecology; Applied ecology; Barium; Biological and medical sciences; Centropristis striata; Chemicals; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fish; Fish populations; Fundamental and applied biological sciences. Psychology; Identification and classification; Isotopes; Larvae; Marine; Marine conservation; Marine fish; Marine fishes; Mass spectrometry; Observations; Otoliths; Pisces; Spawning; Stable isotopes; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Water
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/f06-048

We describe a new technique for transgenerational marking of embryonic otoliths that promises significant advancements in the study of larval dispersal and population connectivity in marine fishes. The approach is based on maternal transmission of 137 Ba from spawning females to egg material that is ultimately incorporated into the otoliths of embryos produced by an individual after exposure to the isotope. We injected females of a benthic-spawning clownfish (Amphiprion melanopus) and a pelagic-spawning serranid (Centropristis striata) with enriched 137 BaCl 2 and then reared the resulting progeny through to settlement. Barium isotope ratios in the cores of larval otoliths were quantified using laser ablation inductively coupled plasma mass spectrometry. Larval otoliths from both species contained unequivocal Ba isotope signatures over a wide range of doses (0.8–23 µg 137 Ba·g female –1 ). Female A. melanopus continued to produce marked larvae over multiple clutches and for at least 90 days after a single injection. The ability to administer different combinations of stable Ba isotopes provides a new means of mass-marking larvae of benthic- and pelagic-spawning fishes from multiple populations over extended spawning periods.