XVII.—THE TRANSFORMATION OF SALT MARSHES INTO FISH 
PONDS. 
By M. DUCASTEL. 
{From “‘ Bulletin mensuel de la Société @acclimatation,” iii series, vol. vi, No. 2, Febru- 
ary, 1879. ]* 
SALT MARSHES. 
The waters of the sea on several points of our western and southern 
coasts are left to evaporate in a natural way in vast basins which are 
called salt marshes (les marais salants). These basins vary in shape and 
depth, and the water of the sea passes successively from one to the 
other. In the last basins (those nearest shore), where the water is only 
a few centimeters deep, the salt is deposited under conditions which 
vary in the different localities. Thus, in the salt-pits of the west the 
first deposit of salt is gray, and in order to give it a white color it is 
necessary to subject it to a refining process, whilst in the south the 
salt obtained from the salt-pits is white and pure. 
The salt harvest depends altogether on atmospheric influences, such 
as the heat of the sun and the winds which more or less favor the evap- 
oration of the water. In many places, especially in the West, the salt 
harvest will be almost an entire failure when the season is rainy or cool. 
Vast pieces of ground, on which considerable sums of money have 
been spent, therefore become almost entirely unproductive. For this 
reason, and in view of the constantly-increasing demands for food for the 
masses, people have in many places been led to abandon the manufact- 
ure of salt by the spontaneous evaporation of the sea-water, and have 
begun to utilize to greater advantage the grounds once devoted to this 
industry by transforming in them into fish-ponds. 
The ponds of this kind which have been constructed on the coast of 
the basin of Arcachon, in the department of Gironde, are excellent models 
of such fish ponds, and cannot be too highly recommended to the atten- 
tion of the owners of salt marshes. 
THE PONDS OF THE ARCACHON BASIN. 
By ministerial order of August 6, 1852, Mr. Coste was commissioned 
* Transformation des marais salants en réservoirs a poissons. Translated by HERMAN 
JACOBSON. 517 
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