Can calcein and alizarin complexone be used for double immersion marking of juvenile qingbo Spinibarbus sinensis?

Abstract

Calcein (CAL) from 50 to 250 mg/l and alizarin complexone (ALC) from 100 to 300 mg/l were used for double immersion marking of juvenile qingbo Spinibarbus sinensis. With the exception of the scales, double immersion for 24 h produced detectable double marks in otoliths (sagittas and asterisci), barbs, fin rays (dorsal, pectoral, ventral, anal, and caudal), and fin spines (dorsal, pectoral, ventral, and anal) after 90 days in a laboratory growth experiment. Green fluorescent rings produced by CAL were considerably closer to the inside of the bony structures (including otoliths, barbs, fin rays, and fin spines) than red fluorescent rings produced by ALC. Sagittas, asterisci, and barbs showed acceptable fluorescent marks at higher concentrations (250 mg/l CAL and ≥ 200 mg/l ALC, ≥ 200 mg/l CAL and 300 mg/l ALC, 150–250 mg/l CAL and 250–300 mg/l ALC, respectively). Fin rays and fin spines treated by 200 mg/l CAL and 250 mg/l ALC and 250 mg/l CAL and 300 mg/l ALC simultaneously had both acceptable CAL and ALC marks. There was no statistically significant difference on the survival or growth of marked fish compared to the controls throughout the experiment (p > 0.05). The results suggest that double immersion with CAL and ALC is suitable for double mass-marking of juvenile S. sinensis, and these double marks are useful in the experimental development of biological research or restocking methodologies.