Morphoecology in larval fin-fish: A new candidate species for aquaculture, Diplodus puntazzo (Sparidae)

This study was aimed to acquire information on trophic behavior of Diplodus puntazzo larvae and juveniles, by studing the ontogenetic sensory development, except vision. D. puntazzo specimens were observed using a scanning electron (n = 67) and a light microscope (n = 7). The results concerned four ontogenetical stages of sharpsnout seabream: larval, post-larval, transitional, and juvenile stages. The yolk-sac larval stage was not detected as the smallest larvae at our disposal (3.1 mm TL; 2nd day from hatching) showed no external appearance of the yolk. During the larval stage (3.1–4.7 mm TL), sharpsnout seabream is equipped with free neuromasts and olfactory ciliated receptor cells. In the post-larval stage (5– 28.6 mm TL), mechano- and chemo-reception is implemented: the inner and outer taste buds differentiation, the nasal formation, the lateral line system canalization occur. The precocious differentiation of chemo-receptors makes post-larvae particularly sensitive to the organoleptic properties of administered preys. D. puntazzo, at the end of this phase, could be considered a juvenile (complete squamation is acquired), except for the mouth and pharyngeal teeth. During the subsequent phase (‘transitional’), in fact, eight chisel-type and two lateral series of molar-like teeth progressively substituted the conical ones on each jaw, and three different types of teeth on the upper and lower pharynx differentiated. So, the juvenile phase is reached in individuals longer than 58 mm TL.