Thursday, April 21, 2005

Glossary: Shellfish Gathering

The use of shellfish as a primary source of protein has been linked by some researchers with the development of modern homo sapiens.

The earliest anatomically modern humans are associated with shell mounds in South Africa dating to 100,000 years ago. According to one theory of human migrations out of Africa along a southern route, populations hugged the coast because of their shellfish gathering practices.

The human nervous system, like that of all mammals, is composed almost entirely of long-chain polyunsaturated fatty acids (LC-PUFA), docosahexaenoic acid (DHA) and arachidonic acid (AA).

These essential fatty acids are generally lacking in land-based animals but high in in fish and shellfish. A study by Broadhurst et al. suggests that the move to shellfish and fish as major parts of the diet is linked with the brain development in early humans. They argue that such a diet "would have provided the advantage in multi-generational brain development which would have made possible the advent of H. sapiens. Restriction to land based foods as postulated by the savannah and other hypotheses would have led to degeneration of the brain and vascular system as happened without exception in all other land based apes and mammals as they evolved larger bodies."

The building of shell mounds by shellfish gathering people eventually took on a cultural form that is rather distinctive. The mounds were usually built at some distance from the community at first. Studies have suggested that the depth of shell mounds increases by about 8 inches to 1 foot per 100 years.

Eventually as the mounds grew high enough the community would often relocate on top of the structure. The raised elevation provided protection from floods and tides. Once on top of the mound, the midden continued to grow. Some waste was disposed of right under the home over the existing midden, while other types of waste were moved to a nearby dump that tended to extend the size of the current mound.

Some middens were also used as burial grounds and platforms for ceremonies. In cultures that still build shell mounds like the sea gypsies of Southeast Asia, the Andaman Islanders and the Nicobar Islanders, the heaps are a source of pride for the community.

Surface of a shell mound, Andaman Islands

In shellfish gathering cultures, the work tends to be done by women while men hunt, fish or do other chores. Consumption of shellfish and fish, on the one hand, is associated with nomadic and underdeveloped communities, and on the other with the food of the world's elite i.e., caviar, escargot, sashimi and oysters.

In the islands of Southeast Asia, shells were formed into blade tools during the early or pre-Neolithic period. These tools were often made from the operculum. In addition to their use as blades, shells were also used for bailers, scrapers, sanders, hooks, shovels and other instruments.

For some uses, shell tools were superior to those made of stone, while inferior for other uses. This situation may have sparked the trade of shell for stone tools and vice a versa in early Southeast Asian cultures.

The value of shells and their availability to seafaring merchants probably led to their eventual use as the first trade currency. The cowrie became the principal shell for this purpose over much of the world.

When the Phoenicians developed coins for trade they made them into the shapes of murex, scallop and triton shells. Today shells are displayed on the coinage of various countries.

Imperial Volute (Cymbiola imperialis Linne) on Philippine sentimo coin

Triton's Trumpet (Charonia tritonis Linne) on Vanuatu 2 vatu coin

Paul Kekai Manansala


Broadhurst CL, Wang Y, Crawford MA, Cunnane SC, Parkington JE, Schmidt WF. "Brain-specific lipids from marine, lacustrine, or terrestrial food resources: potential impact on early African Homo sapiens." Comp Biochem Physiol B Biochem Mol Biol. 2002 Apr;131(4):653-73.

Shellfish as Trade Goods,