Abstract

Otoliths, calcium carbonate concretion of fish inner ear, are used to determine age and growth, for taxonomic purposes, to reconstruct life history in individuals and to discriminate fish stocks. Sagittae morphological characteristics were described in twenty species of highly economical important fishes form southern Gulf of Mexico. These species belong to the Epinephelidae (Groupers), Labridae (Wrasses) and Lutjanidae (Snappers) families. Scanning electron microscopy was used to obtain digital images in which morphological characteristics of the inner face of the sagitta (saccular otolith) were recorded. Sagittae were air dried, gold and platinum sputter-coated, and mounted on an aluminum stub using double-sided carbon tape. Images were acquired through a SEM Phillips XL 30 at 25 KV. Right and left sagittae measurements recorded, using the image processing software Image Pro Plus, were: area (Ao, mm2), aspect (Aso, %), fractal dimension (Fo), sulcus length (SL, mm), cauda length (CL, mm), ostium length (OSL, mm), rostrum width (RW, mm), and rostrum length (RL, mm). Subsequently, shape indices such as percentage of the sulcus length occupied by the cauda (CL/SL, %), percentage of the sulcus length occupied by the ostium length (OSL/ SL, %) and rostrum aspect ratio (RW/RL, mm) were calculated. To date it is the first description of the sagittae morphology for these species in the area.

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