Abstract
Diatoms are the principal food source for the abalone larvae before switching to eat macroalgae, but most of the diatoms culture systems rely on naturally occurring diatom species to supply live feed to juveniles. Monostrains of Navicula incerta Grunow and Grammatophora marina Ehrenberg benthic diatoms were cultured on wavy plastic plates (so called "Papan") in the laboratory. The settlement of abalone larvae and growth of abalone spat were compared with using diatoms live feed of N. incerta monostrain (NIM), G. marina monostrain (GMM) and wild mixed strains in the abalone hatchery. Benthic diatom abundances on papan of NIM, GMM, and WMS were 6.71 x10(5), 7.01x10(5) and 7.56x10(5) cells (cm(2) surf.)(-1) at the beginning of the experiment, whereas at the end, the abundances had decreased to 2.75x10(3), 2.84x10(3), and 3.31x10(3) cells (cm(2) surf.)(-1), respectively. Initially, NIM and GMM diatoms occupied 95.4% and 96.8%, respectively, of the benthic diatom community, which decreased to 69.8% and 65.5% by the end of the experiment. The average number of settled juvenile abalone was 1000, 1080, and 640 in the tank where the live feed was NIM, GMM and WMS, respectively. Survival rates of juvenile abalone were 2.00, 2.16, and 1.28% in the tank of NIM, GMM and WMS, respectively. The specific growth rates of juvenile abalone were 3.28, 3.07, and 2.92% in tanks with NIM, GMM, and WMS, respectively. The average live feed consumption rate by each abalone per day was 0.17, 0.15, and 0.26% of the benthic diatom standing crop in cultures of NIM, GMM, and WMS, respectively. In conclusion, mono-strain benthic diatoms exhibited higher settlement and growth of abalone larvae than did cultures of a wild mixed strain.