Abstract
The bivalve Meretrix lusoria secretes a mucous cord and drifts on tidal flats using the cord as a “sail.” To explain the drifting patterns of the clams in the field obtained in previous studies, conditions affecting cord secretion were examined in the laboratory. The results are summarized as follows: 1) clams over a wide size range (11–45 mm in shell length) secreted cords over a wide range of temperatures (10–30°C) with stimulation by air bubbling of the water and 2) cord-secretion activity depended on the season of collection, with maximum activity in spring and minimum in summer. In general, these results explained well the drifting patterns of the clams observed previously in the field.
