GROWTH OF MYA ARENARIA L. IN THE BAY OF FUNDY REGION

Abstract

Data are presented which demonstrate the validity of "annual rings" as age determinants in Mya arenaria L. The time curve of growth for this latitude depicts a relatively rapid rate during the first four years, after which a pronounced decrease obtains. Relatively little variation has been found in the rate of growth characterizing the widely separated parts of the Bay studied. In general, specimens 18 mm. in length grow about 12 mm. (66%) in one year and those 26 mm. grow about 9 mm. (33%). These represent typical values for growth in the Bay of Fundy region under favorable conditions.The length of the growing season during 1931 was approximately four months, —May to August, inclusive. During 1930, growth continued until about Dec. 1. Such a late fall growth is considered unusual for the Bay of Fundy region.Data are presented which show that variations in seasonal growth rates during the same and different years correspond with abundance of diatoms and not with temperature. The rate of growth has been found to vary directly with time of submergence. Wide variations in salinity and sulphide content of the beach are required to reduce the amount of growth significantly. Excess surface silt on the beach limits the growth rate and survival time of Mya arenaria.