520 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 
The “sleeve” is a net in the shape of a truncated cone, 7 meters long; 
its opening is underneath the frame to which it is fastened; it must, 
under all circumstances, have from 550 to 600 meshes of 11 to 12 milli- 
meters all round, and 120 for the small opening; the large opening is 
fastened on a wooden frame, either with nails or with a cord passed 
through holes in the frame. 
Filling and emptying.—The ponds are filled with sea-water for the pur- 
pose of renewing the water, of providing food for the fish, and of ob- 
taining young fry for the ponds. 
The filling process, as a general rule, does not commence till the 15th 
of March, and lasts till the Ist of November. This period is subject, 
however, to slight changes occasioned by the temperature and commer- 
cial necessities, such as the sale of fish. Easter is generally the time 
when the filling process commences. 
This process is only carried on twelve days in the month, and twice a 
day, in the evening and in the morning. These twelve days are divided 
into two periods of six days each. The filling process is carried on for 
six days during every tide of the syzygies (new moon and full moon). 
These tides are always very strong; their height, however, varies accord- 
ing to the east and west wind. A south wind causes the tide to rise the 
highest, whilst a north or northeast wind makes it rise the least. 
In order to cause the fry to enter by the “sleeve” (manche) system, 
the frame with its “sleeve” is let down, so as to prevent the fish from 
escaping; two hours before the sea is on a level with the water of the fish- 
pond, the gate of the sluice is raised about 7 centimeters, so as to cause a 
small current of water to flow from the fish-pond into the sea, which is 
intended to attract the small fish towards the sluice. In proportion as 
the tide rises the gate is raised a few centimeters, to increase the force 
of the current. When the sea and the water of the fish-pond are on a 
level, the gate is raised entirely; there will then be a current of water 
from the sea into the fish-pond; the higher the tide rises, the stronger 
will be the current; at this period the precaution should, however, be 
taken to lower the gate, for the current might otherwise break the 
“sleeve.” When the current has attained its greatest force, the gate is 
lowered, so as to leave below an open space of only 0.25 to 0.30 millime- 
ter. The small fish are thus drawn into the “sleeve” and thence into 
the fish-pond. 
In employing this method several precautions have tobe taken. When 
the current coming from the seais still weak, the “sleeve” is kept closed 
at the narrow end, and is not opened until the current becomes strong, 
or when the level of the sea, raised by the tide, is 30 centimeters higher 
than that of the water of the fish-pond; because, if this is the case, the 
fish in the pond cannot rise with the current or escape. 
Species of fish which enter the sluices—The species of fish which, by 
means of this contrivance, enter the fish-ponds are as follows: 
