Habitat utilization, population structure, and activity were investigated
for members of the family Coenobitidae on three islets at Enewetak
Atoll, Marshall Islands. Small Coenobita perlatus ( < 8.0-mm carapace length)
were more abundant in the beach habitat than medium-size (8-l9-mm carapace
length)C. perlatus, C. rugosus, C. brevimanus, or Birgus latro. Large C. perlatus
(2: 20-mm carapace length) were present on the beach only at night and engaged
primarily in reproductive behavior. Coenobita rugosus on the beach at night were
generally females which either had recently released their eggs and larvae into the
lagoon or had eggs ready for hatching on their pleopods. The size at maturity was
much smaller for the C. perlatus population on Bokandretok as compared with
populations on Ikuren and Mut. The scarcity of medium-size individuals may
result from a scarcity of suitable Turbo shells
