Size as indicator of swimming speed in crab megalopae

In this work, we evaluated the relationship between swimming speed and size of megalopae of the crabs Uca uruguayensis, Chasmagnathus granulata, Cyrot ograpsus angulatus and C. altimanus in a flume and compared the results wit h the available information for other crab megalopae. Megalopa swimming spe eds ranged from 1.4 cm s(-1) to 13.2 cm s(-1) in C. granulata, 1.02 cm s(-1 ) to 14.9 cm s(-1) in C. angulatus, 1.2 to 6.9 in U. uruguayensis, and 3.3 to 20.8 in C. altimanus. The results of our experiments together with the a vailable information show that, contrary to what is stated in the current l iterature for larvae of similar size, size is a good indicator of swimming speed for crab megalopae. Furthermore, our results suggest that general mod els describing the relationship between size and swimming speed largely und erestimate the average and maximum swimming speed of megalopae.