he distribution and abundance of the white mussel Donax serra Roding was investigated
in 2 log-spiral bays in the eastern Cape, South Africa. The distribution was found to be similar in both bays, abundance lncreaslng to points about 10 and 20 km east of the major rivers, Gamtoos and Sundays, respectively, and declining beyond. The abundance of recruits, 10 to 16 mm in length, peaked closer to the river mouths than the total population. An hypothesis combining longshore drift of immature individuals and larval settlement near river mouths is proposed to explain the differences in longshore populahon structure.