The Growth Rate Of Verruca Stroemia (O. Müller)

Abstract

Data are presented on the growth rate of Verruca stroemia under natural conditions and when exposed continuously and cleaned repeatedly. Several series exposed at different times of the year were followed.Rapid growth takes place (under raft conditions) following settlement; the maximum size is virtually reached in one season's growth between spring and early winter. There is little growth in midwinter.Differences between the mean specific growth rates of the various series can be ascribed to differences in the availability of food.The question is discussed as to whether there is any seasonal rhythm; the evidence indicates that no marked rhythmic pattern of growth exists.Observations on deep-water populations would be of value for comparison and to unmask any relatively weak rhythmic growth.The mean specific growth rates at half their maximum size are compared for several species—Balanus balanoides, B. crenatus, B. balanus, Chthamalus stellatus and Verruca stroemia; it is similar for all species except Chthamalus stellatus. The high level barnacle may require stimulation such as is provided by wave action to elicit full metabolic activity.