376 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
necessary depth of water. Many proprietors, at the approach of cold, remove the 
cases for storage and repairs, leaving the oysters scattered on the bottom of the 
inclosures or parks. 
An oyster park, accordingly, is an inclosed tract intended to retain tidal water 
for purposes of culture (Plates lxxiii aud lxxiv). It is looked upon as an indispensable 
aid to the industry. To scatter oysters broadcast in deep beds, as with us, would be 
especially impracticable in French waters; the oysters would be in constant danger 
either of envasement or the attacks of enemies. It accordingly becomes a matter of 
economy to construct inclosures that permit the oysters to be guarded and tended, 
and that give them at the same time the thrifty conditions of warmer water and of 
littoral feeding. A park may be simply a tract of tide land inclosed by the simplest 
barriers of planks or of interlaced boughs that serve simply to retain the water for a 
few hours (Plate lxxiii, Fig. 1). With this view the simple tidal parks are rarely large, 
perhaps 50 or 100 feet square, to thus give more barriers to hold back the escaping water. 
In outlining the inclosure, account is taken of expense and of resistance to currents. 
For the first reason the barrier need be but a foot or two high; for the second, it often 
requires ballasting with stones. If the current is not a strong one the barrier is con- 
structed in a double line of little fascines. These are of pine or gorse twigs, 10 inches 
high and 5 inches thick (Plate lxxiii, Fig. 2, and Plate lxxiv, Fig. 1). These stand 
upright and are firmly implanted, the space between the parallel lines packed with 
sand and clay, and they form ultimately a wide, low, park margin both water-tight and 
durable. This inclosure, by keeping the rearing cases continually under the surface, 
also serves an additional use, considered of great importance in the French localities, 
that of giving more space for culture, since it brings into use a higher zone of the 
beach. Should the bottom of the park be not too soft,* it may be thickly strewn with 
half- grown oysters ; the cases then vacant are at once refilled with seed. The elevage 
of the dredged oysters, as we have noted, is of this character; they are simply scat- 
tered regularly over the park bottom and allowed to fatten under the thrifty condi- 
tions of littoral feeding in warmer water. As a rule, accumulation of sediment does 
not interfere with culture iu these parks. Should the barriers prove not water-tight, 
a marginal draining trench is naturally formed and the escaping current bears away 
a great part of the sediment with it. 
The more costly oyster parks differ from these primitive inclosures only in the 
character of their walls. Stone walls, massively masoned, render the structure per- 
manent, while mechauical gates regulate with nicety the depth aud renewal of water. 
An especial use of this kind of park is that of vivier for the storage of marketable 
oysters, especially during the winter season (Plate lxxvi, Fig. 1). 
The simplest kind of barrier park is well seen at Gancale (Plate lxxiii, Fig. 1). 
Here the entire sweep of muddy or sandy shoals may at low tide be seen checkered off 
in rough inclosures. The barriers that outline them noted in the figure are formed of 
rough planks well covered with seaweed, held in position by firmly implanted stakes. 
The center of the park is seen to be drained and the thickly spread oysters are ex- 
posed. These parks may be drained at the side by withdrawing a small wooden vane; 
the collecting sediment is then carried seaward down the intervening alleyway. The 
Mud a foot thick is not regarded as detrimental. The oysters keep readily upon the surface. 
