584 BULLETIN OF THE BUREAU OF FISHERIES. 
the requirements for planting 1 acre with a sponge on each square yard of 
bottom. 
For plain disks: 
#;840 disks, at. 2:Cents! 222. oon ce ean eee te ee re OTE 
4840 Cuttings at 2:centse 22 cess eo ae ee ee yy ees de ee oe ee 
Labor, planting: fifteen/days; at. $2 =-'o 2. 222 ee sneak oS ee ee ee OD 
223.60 
For disks with short lead spindles: 
A840: disks, ‘at.2t4,centsiess Ow 20/32: DS ee ee eee a eee ee ee See 121.00 
4,840. cuttings; at 2 cents... = 22 = os ee = eee ee eine aoe --- 96.80 
Tabor isre: days: ati Boe 5 26 em ee ee ae ee 12.00 
229. 80 
The first cost is slightly in favor of the plain disks, the expense for aluminum 
binding wire being so small as to be negligible, but when it is remembered that 
both kinds of disks are available for subsequent plantings when recovered, this 
advantage disappears. Assuming that during four years of growth 20 per cent 
of the original cuttings die and that the disks to which they were attached are 
lost on account of their inconspicuousness, each of the above accounts would 
have to be credited with the value of the disks recovered, 80 per cent, amounting 
to $77.44 in the first case and $96.80 in the second, making the actual cost of 
planting in the two cases $146.16 and $133, respectively. 
In subsequent use of the disks for replanting, especially in deep water 
where a diver is employed, the advantage is strongly in favor of the disks with 
spindles for reasons that have been already explained. The cost of harvesting 
the sponges can not be stated, as there are no adequate data available. In 
shoal water, where the sponges could be taken by hooks and the replanting 
with fresh cuttings be carried on simultaneously, the cost would be slight. 
Where a diver would have to be employed the expense would be heavier, but 
by using the spindles this could also be reduced by planting fresh cuttings as 
fast as the mature sponges are taken, without removing the disks from the 
bottom. In most localities in deep water there would also be a compensatory 
greater return on account of the superior quality of the sponges. 
Assuming that there is no expense in guarding the beds, but that this 
service is incidentally performed by the men making the disks and planting the 
sponges, the apparent profits to be derived from sponge planting are as follows: 
Net cost of planting 1 acre with) 4:S4o) cuttings: -=--9' = ae ee ee $133 
Value of 3,872 sponges (80 per cent of 45840); at. 25 cents —2— = 22 32-22 = -  S 
Thus, at the end of four years from the date of planting, the net value of 
the sponges on the bottom would be $835, assuming that they had grown at the 
rate demonstrated at Anclote Key and had attained an average weight of 
114 ounces, dry, that the mortality during their growth was 20 percent, and that 
