Retention of a transgenerational marker (137Barium) in tissues of adult female anemonefish and assessment of physiological stress
Roy, A-S and Frisch, AJ and Syms, C and Thorrold, SR and Jones, GP, Retention of a transgenerational marker (137Barium) in tissues of adult female anemonefish and assessment of physiological stress, Environmental Biology of Fishes, 96, (4) pp. 459-466. ISSN 0378-1909 (2013) [Refereed Article]
Recently it was shown that female fish injected with enriched stable isotopes maternally transmit a chemical signature to larval otoliths. Validation of this larval marking technique requires laboratory experiments to determine appropriate injection concentrations and to assess any negative effects on larval and adult condition. This study investigated the temporal profile of 137barium assimilation and retention in tissues of adult female anemonefish Amphiprion melanopus (Pomacentridae) following intraperitoneal injection with either 2 or 4 μg 137Ba g−1 body mass. Mean barium isotope ratios (138Ba:137Ba) in the two groups of treated fish were not significantly different from each other, but were significantly different from those in the control group up to 56 days post-injection. This pattern of 137Ba retention was consistent across gonad, muscle, liver and bone tissues. Mean plasma cortisol concentration (an indicator of non-specific physiological stress) was not significantly different among groups and was considered to be representative of unstressed fish. Together, these results indicate that (1) A. melanopus suffer minimal physiological stress and cope well after treatment with 137Ba, (2) 137Ba is retained in female A. melanopus for a prolonged period (at least 56 days), such that multiple clutches of offspring are likely to be marked with an isotopic signature, and (3) a lower dosage of 2 μg 137Ba g−1 appears sufficient for transgenerational marking. It is concluded that 137Ba is suitable for use as a transgenerational marker and is a powerful tool to resolve long-standing enigmas such as larval dispersal distances and the fishery benefits of marine reserves.