[13] TRANSFORMATION OF SALT MARSHES INTO FISH-PONDS, 529 
Tn all cases, however, the line EK I’ must touch the bottom, and the line 
A B must rise 0.50 millimeter above the level of the water, so as to pre- 
vent the mullet from leaping over the frame and escaping in that man. 
ner. The frame runs in two posts with grooves. ; 
Manufacture and preparation of “sleeves.,—At Bordeaux sleeves” 
are prepared by the process employed for preserving awnings and sails. 
This process imparts to the the twine a greenish color. It costs, per 
“sleeve,” from 1 frane 75 centimes (54 cents) to 2 franes (39 cents), ac- 
cording to the weight, and makes a “sleeve” last one-third as long 
again as it would have lasted otherwise. A “sleeve” without prepara- 
tion costs 25 franes. 
This apparatus is made at bassens (12 kilometers from Bordeaux) by 
women and children; the twine is manufactured at Tonneins (Depart- 
ment of Lot et Garonne); in making a “sleeve” 10 frances’ worth ($1.93) 
of twine isused; the maker gets 10 francs, and theprofit of the merchant 
is 5 frances (96.5 cents). 
If a “sleeve” has been well prepared it will last one year; this will 
greatly depend on the quantity of detritus, refuse, and plants floating 
in the sea and drifted towards the “sleeve”; sometimes a “sleeve” 
will last eighteen months; but as a general rule a “sleeve” without 
preparation becomes worn out in about eight months. 
It will be good to immerse the “sleeve” from time to time in tan (an 
infusion of the bark of oak), which gives to the twine a reddish color. 
STOCKING THE FISH-PONDS. 
Process of stocking.—The following kinds of tish when quite young are 
made to pass from the sea into the fish-ponds by means of sluices: 
Mullets, commonly known as “mules,”: enter in large numbers and 
form the most important part of the population of the ponds. 
Barbels, commonly known as “ brignes,” only enter in small numbers. 
Eels enter in large numbers in spring, when the sluices ave opened. 
The introduction of young fry into the ponds by means of a net 
(“sleeve”). placed in the sluice often causes too large a quantity of 
barbels and eels to enter at the same time, which is not desirable, as 
these fish are exceedingly voracious, and are apt to devour all the 
young fry of the mullet. The only means of warding off this danger 
is to gather but few young mullet in the “sleeve,” and to raise young 
mullet by artificially impregnating their eggs, which are generally emit- 
ted by the spawning process at the end of June or the beginning of 
July. By replacing the “sleeve” with a metallic frame (not letting any 
sea-water enter), and by hatching fecundated eggs only of the better 
kinds of mullet, the pond will be exclusively stocked with these fish, 
the cultivation of which is far more profitable than that of the barbels 
and eels. It may be well to state, in this connection, that the mullets, 
more especially the black ones, can easily stand saltness varying from 
zero to 8 degrees of Baumé’s areometer, and a degree of heat and cold 
which would cause most other fish fo perish. 
S. Mis. 29 o4 
