Abstract

The developmental pattern in the mid-intertidal mussel Perumytilus purpuratus was investigated through laboratory cultures. Larval development, growth, survival rate, and time to reach the post-larval stage were determined using triplicated feeding/non-feeding treatments in artificial seawater at 18.2 +/- 0.5 degrees C. Development of the larval digestive system was examined histologically. We found that P. purpuratus have ova (121.1 +/- 2.7 mu m diameter) with a jelly coating, the digestive system develops in the trochophore, the veliger shell has a large prodissoconch-1 and a small prodissoconch-2, the larval period lasted between 10 and 14 days, and larvae could reach metamorphosis without the presence of particulate food. Unlike most of the mytilid species with pelagic larvae, a facultative planktotrophic development is evident in this species. This developmental pattern could be favourable in unstable and changing environments such as rocky shores.