Santander, February 19th-22nd 2008 - Aranzadi

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CATHERINE DUPONT
Figure 6. Opening scars on the internal side of associated valves of oysters: A (L=92 mm), B (L=120 mm), C (L=107 mm) (photos C. Dupont)
These shell middens are composed mainly of
oysters. Thus, in contrast to shells found in accumulations
of kitchen waste, these middens testify
to a specialized activity, targeted on one species.
Both contain medieval accumulations of oysters
on a muddy Flandrian sediment (Ters and
Viaud 1983) next to the limit of old marshes, now
drained. Baudoin (1916) comments on the serpentine
shape of shell middens at Saint-Michel-en-
L’Herm – a description that is in harmony with the
shape of a marine waterway such as the one at
Beauvoir-sur-Mer. These rivers were broader
during the formation of the shell middens than they
are now. Thus, the oysters could have been transported
by boat from the seashore to shell middens.
Oyster gathering was done by raking natural
oyster-beds on the seashore sometimes during
low tides. At Beauvoir-sur-Mer and Saint-Michelen-L’Herm,
the gatherers did not take the time to
separate smaller oysters from the larger ones
during gathering (Gruet and Prigent 1986,
Baudoin 1916), nor was a selection made prior to
opening the oysters.
In both of these shell middens, some oysters
remained joined. The proportion of joined oysters at
Beauvoir-sur-Mer (28% of MNI) is similar to what
was observed at Saint-Michel-en-L’Herm (22% and
40% for the two samples studied, Gruet and Prigent
1986). The ligament that keeps the two valves joined
was observed at both Beauvoir-sur-Mer and
Saint-Michel-en-L’Herm (Gruet and Prigent 1986;
Quatrefages quoted in Baudoin 1916). More than
59% of the oysters of Beauvoir-sur-Mer (62% at
Saint-Michel-en-L’Herm, Gruet and Prigent 1986)
show opening scars on the edge opposite the
hinge, attesting to fast extraction of the meat without
systematically disassociating the two valves.
But what became of the meat? Levesque
(1982) notes that in 1786 the meat of the largest
oysters could be transported from November to
mid-April without preparation on straw in baskets.
The same process is described in 1873 by the
British doctor Lister (quoted in Levasseur 2005).
Outside of this period it could be salted. Lister
reports that in salt, the meat can be preserved for
more than one month. These oysters “à potage”
MUNIBE Suplemento - Gehigarria 31, 2010
S.C. Aranzadi. Z.E. Donostia/San Sebastián