First record of anomalous otoliths in farmed dusky grouper <i>Epinephelus marginatus</i> (Lowe, 1834)

Abstract Sagittal otoliths are structures that integrate the sensory system of teleost fish, assisting in balance and hearing, which are normally composed of calcium carbonate in the form of aragonite. The dusky grouper Epinephelus marginatus has great economic importance and there are already initiatives to produce this species through aquaculture. This study aimed to check the frequency of anomalous otoliths and to characterize the crystallization of sagittal otoliths in E. marginatus from a rearing system. We examined sagittal otoliths of 184 E. marginatus , most otoliths presented normal morphology ( n = 152; TL = 24.0 ± 3.59 cm; OW = 0.034 ± 0.014 g), while about 17% were deformed ( n = 32; TL = 29.7 ± 1.87 cm; OW mean = 0.040 ± 0.011 g). Raman spectroscopy detected aragonite deposition in all normal and anomalous otoliths. The morphological changes in otoliths of groupers may have been caused by transport between hatchery and fattening locations, by the constant flow of aeration during hatchery rearing, or even by a possible starvation period.