508 BULLETIN OF THE BUREAU OF FISHERIES. 
of turbid water, the effectiveness of which we can determine by a comparison 
of the present condition of the grounds with their past. 
Restrictions upon the character, amount, and location of apparatus and 
methods are designed either to suppress destructive or wasteful fisheries or to 
curtail the use of efficient methods which are not inherently destructive or 
wasteful, though they may become so in the employ of the reckless or unprin- 
cipled. Examples of the first type of legislation are seen in the prohibition of the 
use of the dredge in Florida, the Bahamas, Cuba, and Cyprus and its restriction 
to great depths off the Egyptian coast. There is no doubt that such regulation 
is in the interests of the fisheries. The dredge has no place in a well-regulated 
fishery in depths approaching those that can be exploited by other means. It 
may be effective, but it is also inordinately destructive, and the sponge fisheries 
of this day are in no condition to support unnecessary and preventable waste. 
The federal and state legislation restricting the use of the diving machine 
to depths of not less than 50 feet is an example of the second type of restriction 
of apparatus. Properly conducted diving is inherently neither destructive nor 
wasteful. Its chief menace to the beds, if the taking of young sponges be pre- 
vented, lies in its ‘efficiency and the thoroughness with which it operates to 
denude them. It is intense in its effect, and the legislation directed at it is 
intended to confine and limit it and to preserve both the inshore and offshore 
beds by practically restricting its efficiency and the volume of its catch. The 
restriction of the scaphander to water deeper than 50 feet is absolutely necessary 
for the conservation of the beds already shrinking under the operations of the 
hookers. Later it may be necessary to protect the divers from themselves and 
fix a maximum depth beyond which they may not go. 
The three general means of regulating and conserving the sponge fisheries 
above discussed are applicable to the public beds, limiting the intensity of the 
fishery, aiming to secure and maintain what we have rather than hoping to add 
toit. They are restrictive and conservative rather than constructive, and with- 
out the discovery of new grounds offer little hope of maintaining the supply in 
equilibrium with the constantly growing demand. 
‘The fourth method, sponge culture, is on the contrary concerned with the 
sponge industry rather than the sponge beds. It is constructive, aiming to add 
to the sponge supply of the future without particular regard to the source of 
supply of the present. It apparently offers the only hope of permanently 
maintaining the sponge fisheries in those countries in which they are now estab- 
lished, though the discovery of extensive beds in other parts of the world may 
make it not absolutely necessary for the prevention of an ultimate sponge 
famine. As it is at present not applicable to the public beds, but even more 
than oyster culture susceptible of development by private enterprise only, dis- 
cussion of it is reserved for another paper. 
