Meeting Abstract

P1.186  Wednesday, Jan. 4  A Seven Year Study of Shell Use by Coenobita clypeatus(/i)> on Cayos Cochinos Mejor, Bay Islands, Honduras GILCHRIST, Sandra L; New College of Florida, Sarasota

Adult land hermit crabs, Coenobita clypeatus (J.C. Fabricius 1787), must find shells or other abdominal coverings throughout their lives. Shells can come from fresh water, marine or terrestrial sources. Fresh water is also a critical resource for these crabs, allowing them to regulate temperature as well as maintain hemolymph balance. Some authors have noted that these hermit crabs find shells along beaches near wrack lines while others indicate that shell collection areas such as tree holes and beneath fallen trees provide shell resources. A seven year study of shell cycling and fresh water access on Cayos Cochinos Mejor supports the notion that crabs frequent shell collection areas close to fresh water sources. Introduced shells farther from fresh water access are not located as quickly. Crabs at collection sites exchange shells even when there is an excess of new shells available. Mark/recapture studies reveal that the mean size of the crabs did not change over the sampling period despite the addition of several thousand large shells over the seven years. There were fluctuations in shell crowding during each sampling season, but not a significant change across seasons. Crabs visiting collection areas near fresh water had a mean larger size as well as a wider size range than sites farther from fresh water. Shells were retained in the system for at least 5 years, though the quality of the shell declined over time. This study was permitted by DIGIPESCA through the generosity of the Honduran Government.