THE COMMERCIAL SPONGES AND THE SPONGE FISHERIES. 497 
average production per diving boat per month of actual operation, as nearly 
as can be ascertained, has been 385 pounds in 1905, 437 pounds in 1906, 338 
pounds in 1907, and 206 pounds in 1908. ‘The latter part of 1907 and the 
entire spring of 1908 was characterized by boisterous weather, and part of the 
decrease may be due to these conditions. 
So far as we can judge from the statistics, however, and making due allow- 
ance for the uncertainties of the fishery, there appears to have been a consider- 
able decrease in the productiveness of the beds, especially in the Gulf of Mexico, 
since 1900, a statement which is*strongly supported by the observations of those 
engaged in the fishery. 
HOOKING AND HARPOONING. 
Hooking and harpooning are essentially the same and are limited by the 
same conditions. They can be carried on only when the weather is moderate 
and the water clear, and as the latter essential may occur on some beds only 
at intervals of several years, as, for instance, on the New grounds off Cape Sable 
and in the deeper water on the Bay grounds, there is imposed on these methods 
of fishery certain natural and irrefrangible close seasons which operate to effec- 
tually protect certain beds by restraining the fishery for sufficient periods to 
permit of recuperation. In most places, however, clear water is the rule rather 
than the rare exception; and in such cases hooking, while temporarily inhibited, 
may be carried on for a greater or less part of each year. When this is the case 
the effects on the beds are dependent upon the intensity of the fishery and the 
degree to which the fishers rob the grounds of young sponges. As arule, wherever 
the beds are sufficiently productive to make it profitable they are worked beyond 
reasonable limits until more or less gradually the yield is reduced below the 
economic minimum and most of the spongers withdraw to other fields, leaving, 
however, enough of their less enterprising fellows to prevent the possibility of 
effective recuperation. This has been the case on the Key grounds of Florida, 
where the fishery continues to produce a small crop, though abandoned as 
unprofitable by most of the vessels and some of the boats. The New grounds, 
where the water is found clear only at intervals of several years, still produce 
sponges under favorable conditions, while several other places—for instance, 
the vicinity of Bamboo Key, which were almost abandoned for a while—have 
again become moderately productive. 
In connection with the hook fishery there are two factors which assist in 
the recuperation of the beds. One is the presence of sponges in adjoining waters 
too deep to be reached with the hooks, and the other is the retention on the beds 
actually fished of sponges which are out of sight from the surface. This is more 
fully discussed in connection with diving. Another factor assisting in the recu- 
peration of the beds reserved to hookers is the regenerative growth of fragments 
. B. B. F. 1908—32 
