180 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



and excellent quality, such as do not now exist in the bay. The ground 

 was resorted to by people from all over the bay, and many boat loads 

 were taken annually for local use. The quality of these oysters is 

 thought to have been due to the breaking np of the dense clusters and 

 the scattering of the oysters by the people who visited the ground, so 

 that in time the oysters partook of tlie character of ])lanted stock. None 

 of these oysters have been found in the creek since the fiimous hurricane 

 of 1878, when tlie sea washed into the creek and the beds were destroyed 

 by being covered with sand. 



SPONGES. 



South of a line drawn west from Cape Florida sponges are found in 

 great abundance. Besides loggerhead sponges, sulphur sponges, and 

 other nonmerchantable species, which exist in remarkable profusion, 

 there are the valuable sheepswool, yellow, and grass sponges. The 

 commercial species are well distributed throughout the southern part 

 of the bay, growing on muddy and rocky bottom. The relative fresh- 

 ness of the water in that part of the bay north of Cape Florida pre- 

 cludes the existence of the desirable sponges. The specific gravity of 

 the water in the bay opposite the cape on February 18 was 1.023. As 

 about the normal amount of fresh water was at that time being brought 

 down by the Miami, Little, and other rivers, the figure given may be 

 taken as approximating the mean density of that part of the bay and 

 as marking the minimum density in which the economic sponges are 

 found. While loggerhead and other useless species were observed 

 some miles north of that position, in water having a specific gravity 

 as low as 1.019, few sheepswool or other similar sponges exist in water 

 having a lower density than 1.023. 



Of the marketable sponges growing in Biscayne Bay, the most 

 abundant and valuable are the sheepswool. These grow very rapidly, 

 and some specimens of large size are obtained, notwithstanding the 

 comparative facility witli which the grounds are worked and the assi- 

 duity with which the business has been carried on. The yellow sponge 

 ranks next to the sheepswool sponge in abundance and value, and then 

 comes the grass sponge. On the authority of experienced sponge 

 fishermen and dealers, it may be stated that the sponges in the bay are 

 of a finer quality and grow faster than those found on the ocean reefs, 

 although the latter, extending from Key West to Cape Florida, of 

 course constitute a much more productive ground. 



Off Elliott Key and Cjcsar Creek, in Biscayne Bay, sponges are 

 found within a short distance of the shore and are said to grow faster 

 than elsewhere in the bay. Some of the finest si)onges ever obtained 

 in the waters of Florida have been taken near Elliott Key. On Feath- 

 erbed Bank, which is a narrow shoal extending across the bay opposite 

 Kagged Keys and has from 1 to G feet of water, si)onges also grow 

 rapidly, and some good specimens have at times been taken on that 

 very shallow ground. 



