Staining of larval abalone (haliotis midae) shells using two epifluorescent dyes

Abstract

ABSTRACT A nontoxic method that results in distinct and persistent marks in Haliotis midae juveniles is fundamental for field-based studies, abalone ranching, and stock enhancement programs. Developed (6 days after fertilization) H. midae larvae were batch-tagged with 25 and 50 mg L−1 of calcein and xylenol orange for 24 and 48 h to determine the effect on survival, settlement, and the persistence of the mark on the shell. Epifluorescence was detected in the shell spire of larvae tagged with either 25 mg L−1 or 50 mg L−1 of calcein for 24 and 48 h immediately after the staining (t0) and was visible after 51 days when the experiment was terminated. Survival of calcein stained larvae was higher after 24 h compared to 48 h immersion. However, percentage settlement was higher in the 48 h treatments when compared to 24 h treatments for both concentrations and dyes. Therefore, bright and persistent epifluorescence marks can be induced in H. midae shells using calcein (25 mg L−1 for 24 h) without negatively affecting the survival and settlement of larvae, post-immersion.