EARLY LIFE CYCLE OF THE PACIFIC THORNY OYSTER SPONDYLUS CRASSISQUAMA (LAMARK, 1819)

Some genera of bivalve molluscs have an iconic ancestral history that predominates in the culture of a civilization through time. The Pacific thorny oyster Spondylus crassisquama is a living example of this. This study presents the description of the early life cycle until obtaining juveniles; and, for the latter, different types of substrates were evaluated. Larval culture was developed under laboratory conditions, chronologically recording the changes in larval morphology and behavior. The thorny oyster presents the first cell cleavage at 50 min postfertilization (PF). The transition between trochophore phase and the first D-veliger larvae was observed around 20-24 h PF. Above 75% of the larvae with presence of a serrate double ring showed ocular eyespot on the 16th day PF. Between the 16th and 18th days PF, the formation of the foot of the larvae was observed. The first postlarvae were observed on the 20th day with a total length of 553.0 +/- 150.10 mu m, distinguished by the appearance of the dissoconch. After 30 days PF, the first settled juveniles were observed with sizes of 1.6 +/- 0.41 mm. Finally, the animals showed a preference for settlement on stones and concrete, and to a lesser extent on broken shells of S. crassisquama. This study shows that juvenile production is feasible under laboratory conditions; however, this requires more research to optimize the nursery process.