REPORT OF THE COMMISSIONER OF FISHERIES. 85. 
that lead wire is too weak to support even its own weight in the lengths 
necessitated by the conditions of the experiment, and in the preceding 
fiscal year the expedient was tried of using ordinary tarred marline 
with a thin casing of lead. The marline supplies the required tensile 
strength, and the lead, besides serving as a protecting covering for the 
cordage, furnishes the desired surface for the attachment of the 
sponges. The cuttings within a week attach themselves to the lead 
and soon form an adhesion sufticiently close to prevent oscillation in 
the waves and yet not so close as to offer an impediment to their 
removal from the wire when it is desired to harvest them. Lead- 
covered marline had been in use for twenty months at the close of the 
fiscal year, and yet showed no indications of impairment in strength. 
It must last twice that long, however, to demonstrate its usefulness. 
When leaded marline was first employed the lines were rigidly 
attached to the stakes, but the continual swaying in the waves caused 
repeated flexure near the point of attachment, and resulted in fractur- 
ing the inductile lead and abrading the marline core to the breaking 
point. A flexible attachment is now employed, and there is no longer 
this difficulty. 
Asbestos cord, treated with a mixture of paraffin and asphaltum and 
incased in lead, and lead-covered underwriters’ wire have also been 
tried, with results in general similar to those above described. 
With the use of lead it became necessary to abandon aluminum wire 
for attaching the sponges and closing the slit, as electrolytic action 
destroyed it before it could serve its purpose. Rubber bands are now 
employed instead, care being exercised to have them of such length, 
compared to the size of the cutting, that no undue pressure is exerted 
on the tissues of the sponge. 
The growth of the sponges during the year has been satisfactory, 
some of them having attained a size of over 5 inches at the age of 
thirty months. Others, eighteen months old, are 4 to 43 inches in 
diameter. At Anclote Key there has been a somewhat alarming 
mortality among the larger ones, and this may indicate the beginning 
of serious difficulties, as there is a possibility that these sponges may 
be approaching their limit of growth, if such exists. At Sugar Loaf 
Key and in Biscayne Bay, where the growth has been slower, this 
difficulty has not developed. During the next fiscal year, this matter 
will receive special attention, as the experiments are now approaching 
a critical stage. No apprehension is felt that insuperable difficulties 
will be encountered. 
THE BLUE CRAB. 
The investigations and study of the life history of the blue crab in 
Chesapeake Bay begun by Prof. W. P. Hay in 1902 have been contin- 
ued by him during the past fiscal year when opportunity offered. 
Many important observations were made at Crisfield, Md., and at 
