Most marine herbivores are generalists, meaning they are able to feed on the three macroalgal lineages, but only few studies have been performed on digestive microbiota in marine herbivores. Bacteria have been shown to help degrade macroalgal polysaccharides in the sea hare Aplysia spp., the snail Tegula funebralis, the limpet Patella pellucida, and the iguana Amblyrhynchus cristatus [21–24], but these studies considered neither different diet types nor seasonality. The abalone, a gastropod of high economic interest especially in China, Korea, South Africa, and Chile [25, 26], is also a generalist herbivore , but its digestive enzymes are not sufficient for macroalgal polysaccharide degradation . This makes the abalone an interesting model to investigate the composition, seasonality, and role of the digestive microbiota associated with several diet types.