Abbreviated Pelagic Life of Chilean and New Zealand Oysters

Abstract

OYSTERS of the genus Ostrea incubate their larvæ In O. edulis, for example, veligers are released from the female when 0.15–0.17 mm long, and afterwards undergo pelagic development, usually of 6–14 days, according to water temperature and food supply, before settling and metamorphosing^1–3. In O. chilensis Philippi from Chile, however, larvæ from incubating females collected by the Lund University Chile Expedition 1948–49 were examined by one of us (R. H. M.), through the courtesy of Dr. T. Soot-Ryen and Prof. H. Brattstrøm, and were found to be 0.45–0.49 mm long and to possess the eye spots and foot which other species develop only at the end of their pelagic life. The other (P. J. H.), who is publishing elsewhere a fuller account of the life-history of the New Zealand mud oyster, O. lutaria Hutton, has observed similar larvæ in that species. These larvæ, when released by the female in laboratory experiments, settled almost immediately. In both species this probably also happens in Nature.