Embryonic development and larval cultivation of Paphia schnelliana (Dunker), a unique economic species of the Beibu Gulf

Abstract

In order to grasp the reproductive biology of Paphia schnelliana and to provide references for seed breeding, the embryonic development, larval growth and morphological changes, movement, and feeding behavior of P. schnelliana were observed. Nine species of microalgae (Chlorella vulgaris, Nannochloropsis oculata, Dunaliella salina, Platymonas subcordiformis, Pavlova viridis, Dicrateria zhanjianggensis, Isochrysis galbana, Chaetoceros muelleri, and Nitzschia closterium) were tested for ingestion and digestion in P. schnelliana larvae using optical microscopy to choose an appropriate diet. Fertilized eggs of P. schnelliana hatched into D-larvae after 16 h and 15 min, the larvae began to ingest microalgae after 19 h and 45 min, and the larvae developed to metamorphosis stage at 9 days post hatch (dph). The growth model of shell length and shell height is that of accelerated growth, and the larva move through the water in a clockwise direction. Of the nine species of microalgae fed, larvae could ingest C. vulgaris, N. oculata, D. salina, P. viridis, D. zhanjianggensis and I. galbana at 1 dph, P. subcordiformis at 2 dph, C. muelleri at 3 dph, and N. closterium could not be ingested during the planktonic period. It was difficult for the larvae to digest C. vulgaris and N. oculata. P. schnelliana spend a short time in embryonic development, hatching, and planktonic larval cultivation. There are a widely variety of microalgal species that can be used for feeding as the newly hatched larvae of P. schnelliana are relatively large. P. schnelliana is a valuable species with potential as a cultivated species.