Digestion indices of 12 species of microalgae by the oyster Crassostrea gigas larval development stages

Abstract

Twelve species of food microalgae were investigated to clarify the digestion index of Crassostrea gigas larvae using epifluorescence microscopy to choose an appropriate diet for artificial seed production in hatchery. An experiment was conducted using 1 (D shaped stage), 4 (Early umbo stage), 8 (umbo stage) and 12 (Full grown stage) days old larvae. larvae were stocked in 1 L flasks at 5 individuals/mL and fed 10×10 4 algal cells/mL of each species individually. Prior to larvae were fed for 3 h and then were observed under the microscope to detect ingestion; larvae were then sieved and replaced in 1 L flasks containing filtered seawater and were observed after Therefore, it is assumed that food microalgae showing the high digestion such as I. galbana should be supplied to the early umbo stage larvae, and then after the umbo larval stage, the mixed microalgae with diatoms and light green algae should be supplied to the full grown stage larvae to increase the digestion of their larvae.Keywords: Digestion index, Epifluorescence microscopy, oyster, Crassostrea gigas, microalgae, larval development. 서 론현재

Genetic diversity assessment of Pacific oyster Magallana gigas (Crassostrea gigas) populations from the two southern coastal farms in South Korea

“…However, changing climates and augmenting anthropogenic activities have significantly reduced natural M. gigas seedlings and led to the point where seeds fell short since 1992 [6]. In response, the farms turned their eyes to hatchery-produced seeds whose weight in the seed market has subsequently increased [7]. New hatchery-propagated stocks could be isolated from the wild populations for genetic improvement, and yet seeds harvested at the limited number of hatcheries would eventually put the M. gigas populations in Korea at risk of inbreeding and genetic deterioration [8].…”