SOME OBSERVATIONS ON THE GROWTH RATE OF SEA URCHINS IN THE GENUS STRONGYLOCENTROTUS

Abstract

Previously published data on growth rate of S. droebachiensis are summarized and examined. Some of these are probably based on S. pallidus. Data obtained from the growth of caged S. droebachiensis on the coast of New Hampshire indicate that these animals grew in mean diameter from approximately 9 to 27 1/2, 25 to 40, 40 to 50, and 51 to 55 1/2 mm in a year. Similar experiments with the same species at Friday Harbor, Washington, indicate a considerably faster growth. Exploratory tests on growth rate were carried out with S. echinoides, S. purpuratus, and S. franciscanus at Friday Harbor.