528 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [12] 
mullet, the hake were thin, but after a few weeks they have grown very 
fat. 
There seems no way of counteracting these powerful causes of de- 
struction but to place a certain quantity of fry in the fish-ponds. This 
destruction of the fry is very much to be regretted, for actual observa- 
tions regarding the growth of fish of prey in the coast-waters, and that of 
mullet in the fish-ponds, show the following result: A thousand young 
mullet left in the basin of Arcachon are, when quite small, devoured 
by fish, whose flesh may be used as food, but which at best only fur- 
nishes half a kilogram of flesh fit to eat; whilst the same number of 
young mullet, placed in fish-ponds and raised there, furnish, when grown, 
more than 1,000 kilograms of the most delicious food. 
Under these conditions, and in view of the constantly rising prices 
of all articles of food, especially animal food, we must say once more, 
and in the most emphatic manner, that. the development and cultiva- 
tion of fish-ponds cannot be too highly recommended, and that where- 
ever they do not yet exist they should certainly be established. 
SLUICES. 
Introduction of young jish—By means of sluices, constructed in con- 
venient places in the dikes which separate the fish-ponds from the Ar- 
cachon Basin, the water of these ponds is renewed, and the fish, when 
still quite young, are introduced into the ponds. 
The sluices are constructed of wood, and consist of four principal 
parts, viz: In the middle, the bridge which is placed against the high 
part of the dike, and which serves as a passage-way; to the right, to- 
wards the fish-pond and leaning against the bridge, there is a post with 
grooves for a large gate; farther on, another post with grooves for the 
“sleeve”; to the left, towards the basin of Arcachon, a third post with 
grooves for a fishing-net. 
Use of the “sleeve.”—The “sleeve” isa net in the shape of a truncated 
cone, 7 meters in length; its opening is exactly underneath the frame 
to which it is attached; it must always have 550 to 600 meshes of 11 
millimeters’ width, on its sides, and about 120 for a B 
the small opening. The net-makers are permitted |------+---++-- 
to make the meshes larger for a portion of the net, | - 
measuring about 3 meters from the small opening; 
but they must gradually decrease in size until they 
have reached 11 millimeters; the small opening 
measures about 30 centimeters in circumference. 
The large opening is attached to a wooden frame, 
cither by nails or by a cord which is passed through 
holes made in the frame. : 
A B=1.10 to 1.30 millimeter. Le Pie¥= if ister ts 
C D=1 to 1.20 millmeters. E F 
A Ei=-The legth or height is proportioned to the depth of the sluice. 
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