530 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [14] 
Rules to be observed in transforming sali marshes into fish-ponds.—In 
transforming salt marshes into fish-ponds the following rules should be 
observed : 
A request should be addressed to the minister of marine asking for 
the privilege of converting into fish-ponds the whole or part of a salt 
marsh. Such a request is never refused. 
The water of the sea should be allowed to flow off by means of 
trenches. 
The saltness should be taken out of the ground by rain-water, either 
by allowing the rain to fall on it, or by gathering the rain-water on the 
neighboring land. 
Whenever there is a sufficient quantity of water from wells or water- 
courses, it is used for watering the ground and for freeing it from the 
greater portion of the sea-salt with which it is impregnated. 
The ground should be allowed to dry until it has reached a degree 
of consistency sufficient to permit of its being worked with a spade. 
The soil gained by digging is used for constructing large and solid 
dikes intended to retain the water in the fish-pond and to prevent the 
water of the sea from flowing into it. 
In these dikes sluices should be constructed for renewing the water 
of the ponds, and for introducing the young and fry of fish. 
By all possible means the growth of Ruppia spiralis in the ponds 
should be encouraged. 
Deep places should be dug in certain portions of the pond, pastures 
should be established, and shelters should be constructed. Rain-water, 
wells, and water-courses should be utilized for the purpose of rendering 
the water of the ponds brackish. 
Regulating the fish-ponds.—These fish-ponds, being fed from the basin 
of Arcachon by means of sluices, were classed among the coast-lisheries ; 
and, although they are located on private property (they were formerly 
salt marshes), they come under the general law of January 9, 1852, for 
regulating such fisheries. 
Before the regulation of July 4, 1853, went into effect, the sluices 
were at their inner opening furnished with a “sleeve” or bag-shaped 
net, 7 meters in length, the meshes of which each formed a square of 11 
to 12 millimeters; the fry that came with the tide were drawn into this 
net and thus carried into the reservoir. The “sleeve” was used {for pre- 
venting both the fry and the young fish, fattened in the ponds, from leav- . 
ing the ponds; and the size of the meshes was arranged accordingly. 
The above-mentioned iegulation has raised these dimensions to 25 and 
15 millimeters: ‘The sluice or way of communication will be closed at 
its inner opening by a wire grating or by a net, the meshes of which shall 
each measure at least 15 millimeters square from the 1st of October till 
the 31st of March, and 25 millimeters from the 1st of April till the 30th 
of November. 
“At the moment when the sea-water enters the ponds there may be 
