EXPERIMENTS ON LARVAL REARING OF THE CALIFORNIA MUSSEL (<i>Mytilus californianus</i>)

Abstract

ABSTRACT Spawning, larval rearing, and settlement of Mytilus californianus were performed over a one‐year period at the University of California, Bodega Marine Laboratory in northern California. A combination of shell scraping followed by a 30 to 60 min immersion in 30 or 60 mM hydrogen peroxide was the most successful spawning stimulus tested. Larvae fed a diet of Isochrysis galbana grew significantly faster than did larvae fed Dunaliella sp. Larval growth rate was significantly more rapid at 20°C than at either 14 or 17°C and no significant differences in mortality rates between these three temperatures were detected. At 17 and 20°C, larvae fed a diet of 80 Isochrysis cells/μ1 daily grew significantly faster than those fed 20 Isochrysis cells/μ1 daily. Mortality of pedi‐veligers was high, but survivors settled and metamorphosed on byssal threads cut from adult M. californianus. Plantigrades had a mean growth rate of 7.8 μm/day between days 15 and 33 following settlement. In this study, a temperature of 20°C, a diet of Isochrysis galbana of at least 80 cells/μ1 daily, and a settlement substrate of byssal threads were the most successful conditions for artificial spat production of this potentially valuable bivalve mollusc.