Salinity, Temperature, and Food Requirements of Soft-Shell Clam Larvae in Laboratory Culture

Abstract

A series of experiments was undertaken to determine (1) suitable methods for spawning and rearing Mya arenaria in the laboratory, and (2) some of the basic environmental requirements of Mya eggs and larvae. Adult Mya did not respond readily to stimuli commonly used to induce laboratory spawning of marine invertebrates and a new technique was developed to provide viable gametes. This technique consisted of cyclic fluctuations in the temperature of the running water in which the ripe clams were held. Larvae were reared through metamorphosis and their tolerance to various levels of temperature and salinity were determined. The optimum temperature range was between about 177deg; and 23°C, although slow development took place as low as 10°C. Optimum salinity was from about 16% to 32% (the highest value tested). Some differences in response to temperature and salinity between larvae from parents of different origins were observed. Several species of unicellular algae were tested as larval food. Although Cyclotella nana produced the best growth, the larvae grew nearly as well on Dicrateria inornata and Phaeodacytylum tricornutum. The last named species was considered most satisfactory, because in addition to promoting good growth, it was most easily raised in culture.