Giant Clams / Hima
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Giant Clams / Hima
Tridacna spp.
Regulated Species
Tridacna maxima
Giant clams, known in Chamoru as "hima," have been important to the people of Guam for many years and are still considered a prized delicacy. Some eat the entire meat of the clam but usually the two large white abductor muscles are the choicest parts for eating.
Guam is known to have had at least four kinds of hima: Tridacna maxima, Tridacna squamosa, Tridacna gigas, and Hippopus hippopus. The latter two species are believed to be extinct on Guam, probably because they were overharvested. The remaining two are still found in our waters. The larger of the two, T. squamosa is rare, and the smaller one, T. maxima, lives tightly attached to rocks and coral on the ocean floor. They are most common in areas of strong water movement or in shallow waters beyond the reef. The lagoon giant clam, Tridacna derasa, which is plentiful in Palau, was intentionally introduced to Guam. Palau has been successful in raising these clams and selling them to other islands such as Guam to help establish them on their reefs.
Tridacna maxima
Images from Coral Reefs CD
Hima have a thick hard hinge on both halves of the shell which can be ground down to make tools. Traditionally, Chamorus collected hima from reef flats. After the meat was taken, the shells were made into tools. Hima use sunlight to grow. They contain plant cells called "zooxanthellae" which use the sun's energy to produce sugars which are used as food by the clam. Hima grow best in areas with clear water and plenty of sunlight. Even under the best conditions, it takes many years for them to reach a large size.
On Guam, hima can only be taken for home consumption from April through July. Commercial harvest is prohibited by law. They must not be smaller than 5.9 inches (15 cm) and no larger than 11.8 inches (30 cm). Only 20 pounds (9 kg) of shells can be taken per day during the season. There are areas on Guam where the harvesting of hima is prohibited. Harvesters should check with the Division of Aquatic & Wildlife Resources for more information on hima regulations and areas closed to harvesting.
Guam Comprehensive Wildlife Conservation Strategy, 9/27/2005
