Prehistoric Shellfish-Harvesting Strategies: Implications from the Growth Patterns of Soft-Shell Clams (Mya Arenaria)

Article excerpt

Shellfish-gathering is the stuff of many a hunter-gatherer economy. It is technically hunting -- the beasties are animals -- but they conveniently sit in the mud and on the rocks ready to be gathered. A new means of studying growth-rings in clam shells gives insight into shellfish-gathering and the seasonal pattern of life-ways in southern New England.

This paper presents an archaeological application of a new method to study the growth patterns of Mya arenaria, the soft-shell clam common along North Atlantic and North Pacific coasts, by cross-sectioning the chondrophore, a small appendage on the hinge region of the left valve that preserves well in archaeological contexts. It complements recent advances in sectioning whole valves of another Atlantic bivalve, the hard-shell clam (Mercenaria mercenaria) (Bernstein 1987; Cerrato 1987; Claassen 1986; Hancock 1984; Kennish 1980; Kerber 1985; McManamon 1984a; 1984b; Quitmyer et al. 1985). Sectioning can now be used to compare and contrast harvesting patterns, age profiles, and growth rates of Mercenaria mercenaria and Mya arenaria that are common in shell deposits along the Atlantic coast of North America.

Clam-harvesting strategies

Atlantic clams represent an expedient, low-risk and relatively predictable food source during most of the year. People of all ages can readily harvest Mercenaria mercenaria and Mya arenaria with minimal tools and facilities. Clam collecting may neatly 'fit' into a diverse range of coastal subsistence-settlement systems, with harvests being scheduled around other environmental, economic and sociopolitical considerations. The relative ease and flexibility of clam collecting has interesting implications for the organization and composition of shellfish gathering parties who may use encounter and targeting strategies.

In the encounter strategy, frequent or even daily collecting forays are made by a segment of the group living in coastal residential bases near productive estuaries. Estuary resources may provide accessible food to 'range-limited' gatherers kept near camp by illness, age, gender, adverse weather conditions, or other reasons (Meehan 1982; 1983; Jones 1991: 435). Specifically, brackish-water shellfish, such as clams, can provide a ready source of fresh meat to young children playing around camp, to mothers nursing infants, to elderly and injured people whose movements are limited, and to everyone when bad weather keeps people close to home.

In the targeting strategy, organized work parties from residential bases harvest specific species of molluscs in great volume. Among contemporary Australian shellfish-gatherers, Meehan (1983: 4-10) notes that organized work parties often 'target' a particular mollusc species found in a specific estuarine habitat for exploitation, with a 'carefully planned strategy'. Estuarine locations are scouted to monitor specific mollusc beds, work parties are recruited and organized, and the movements of people and food back and forth are arranged.

Shelter Island shell deposits

We recently excavated two shell-bearing deposits, the Sungic Midden and Laspia sites, on the Mashomack Preserve, Shelter Island, New York that may have been produced by prehistoric shellfish-gatherers using encounter and targeting strategies (Lightfoot et al. 1987).

Sungic Midden site

Situated along a former estuary (the Sungic Pond), the site consists of a discrete shell-bearing deposit (280 sq. m) surrounded on three sides by an extensive scatter of lithics and ceramics (520 sq. m). A total of seven 1 x 1-m squares were excavated. Three in the shell-bearing deposit yielded marine molluscs, mammal, fish and reptile remains; charred and uncharred seeds and nuts from flotation; and various classes of artefact. Two uncalibrated radiocarbon determinations (1200|+ or -~20 b.p. (Beta-19911), 1240|+ or -~100 b.p. (Beta-19909)) and the presence of Levanna projectile points, scallop-brushed and cordmarked pottery indicate an occupation during the late Middle and Late Woodland periods in coastal New York. …