The effect of starvation on grazing rates of Haliotis fulgens postlarvae

Grazing rates of Haliotis fulgens postlarvae (30, 45, and 60 days old) after different periods of starvation (0, 1, 2, 3, and 4 days) were estimated by the digital analysis of video-recorded images of grazed areas. Trials were conducted in 10ml plastic dishes colonized by the cultured diatom Navicula incerta at standard densities (ca. 250-500 cells/mm super(2)). A significant increase in grazing rates at longer starvation periods was detected. However, for 45 and 60 day-old postlarvae, this increase occurred mostly during the first two days of starvation. The maximum grazing rates for 30, 45, and 60 day-old starved abalones were 3 861, 6 986, and 10 643 cells/postlarva/hour, respectively, which are similar to rates observed in parallel trials at much higher biofilm densities (ca. 4,000 cells/mm super(2)).