PERIODICITY OF GROWTH INCREMENT FORMATION IN OTOLITHS OF JUVENILE GRAY SNAPPER (LUTJANUS GRISEUS) AND LANE SNAPPER (LUTJANUS SYNAGRIS)

摘要

The periodicity of growth increment formation in juvenile gray snap- per (Lutjanus griseus) and lane snapper (L. synagris) sagittal and lapillar otoliths was determined with an otolith marking [alizarin complexone (ALC)] and captive rearing study. Resulting marks of low concentration ALC were located with green epifluorescent light and then confirmed with blue light. Increment formation rate for both types of otoliths and species did not statistically differ from one per day at the 95% significance level. However, in practical terms, the rate of increment formation was less than one per day for the lane snapper lapillar otoliths during the last two weeks of rearing (day 75 sample). Results from sagittal otoliths were more precise than those from lapillar otoliths.