An Archaeological Study of an Artisanal Clam Industry in Costa Rica

Because of my long standing interest in shell middens dating between 7500 and 3500 years B.P. on the coast of Chiapas, Mexico, I undertook a study of a present day clam industry in Costa Rica. The parallels between the modern and ancient shell piles presented me with the extraordinary opportunity to learn more about the ancient past by observing the activities of the 21st century Costa Rican almejeros (clammers). In both regions a small marsh clam, Polymesoda radiata, is the targeted species and in both areas the clams are cooked at sites very close where the clams have been collected.  The cooking locales are located in water logged mangrove swamps so that both the ancient and modern people return over and over again to the same places to process the clams.  This results in the huge build-up of piles of shells at the specialized processing locations. 

My work was funded by the Dixon Emeriti research award at U.C.S.B., This award allowed me to study the claming industry during August, 2005. I was assisted by Natalia Martínez, at that time a student at the Universidad de las Américas, Cholula, Mexico.  Natalia and I interviewed the clammers, and we observed and timed various stages of clam collection, cooking, and preservation.  We also mapped two processing sites to allow comparisons with the ancient shellmounds of Chiapas. 

When the data from our research are compiled and analyzed I will be able to estimate:

• The amount of effort (i.e., time) expended per unit volume & weight of clam meat procured and clam shells discarded.
• The amount of clamshell discarded on an annual basis.
• The amount of clam meat wasted during cooking.
• The cost vs. benefit of the modern artisanal industry that focuses on such a low ranked food resource.
• The nutritional yields per unit effort (by using published nutritional data on these clams).

Natalia Martínez interviewing almejero Gaspar Ovando Silva

Don Gaspar Ovando Silva cooking a batch of marsh clams (Gaspar and cookpot)