would be impossible to build a sound 

 and steady trade. 



Just as the individual farmer must follow 

 sound rules and practices for the biological 

 management of his farm if he hopes to be 

 successful, so sponge fishermen should follow 

 a set of rules and practices if they hope to 

 see an increase in the number of sponges 

 on the sea bottom and maintain the maximum 

 harvest of sponges per year that can be 

 grown. 



It has been shown both by experimental cul- 

 tivation of sponges and the observed concentra- 

 tion that is to be found off Cape Sable in south 

 Florida that even when wool sponges are con- 

 centrated one or more per square yard there is 

 sufficient food in the water for them to grow 

 at the maximum rate for that area. It follows, 

 therefore, that the basic problem is to find 

 ways and means of increasing the concentra- 

 tions of sponges on the available, suitable rock 

 bar areas. Other recommendations made below 

 suggest that the efficiency of harvesting 

 methods might be increased and that future 

 biological investigations should be carried out. 



Recommendations 



Establish a 6-inch size limit . — This recom- 

 mendation has been made many times in the 

 past but has never been acted upon, presumably 

 because of lack of information on larval produc- 

 tion. There has never been any direct evidence 

 presented why a larger size limit is not only 

 desirable but necessary. 



The minimum diameter for egg producing 

 sponges, with few exceptions, is 5-1/2 inches 

 in the area north of Cedar Keys and 5 inches 

 in the area between Tampa Bay and Cedar 

 Keys. It is obvious that the present 5-lnch 

 size limit allows the taking of a number of 

 sponges which have not yet reproduced or are 

 not reproducing in quantity. 



Before a 6-inch size limit is adopted, the 

 immediate disadvantages and future benefits 

 need to be reviewed. 



1. Immediate disadvantages . — At my re- 

 quest, the agents of the Conservation 



Department of the State of Florida made 

 spot checks of the percentages of sponges 

 of less than 6 inches that were being taken 

 by both divers and hookers. Of the sponges 

 examined only 15 percent were wool 

 sponges less than 6 inches in size. This 

 probably represents a minimum percent- 

 age, and some of the hooking boats would 

 probably have some catches with as high 

 as 25 percent wool sponges. 



a. Thus, if a 6-inch size limit were 

 adopted, loss in catch would be at 

 least 15 percent but probably not as 

 high as 25 percent. The loss in revenue 

 would be considerably less than this. 

 As priced by the sponge buyers all the 

 sponges of less than 6 inches in size 

 have an average value per piece of 

 less than half that of the average price 

 for wool sponges. Calculations show 

 that the smaller sizes of sponges of 5 

 to 6 inches do not account for more 

 than 5 percent or 10 percent of the 

 actual cash value of the total take. 



b. In those areas visited by the spongers 

 every year, especially the hooking 

 areas, this loss in revenue would be 

 felt most strongly during the first 

 year after adoption of a 6-inch limit. 

 In the second year those 5- to 6-inch 

 sponges not taken in the area would 

 have grown to hai-vesting size and the 

 greater return from these larger 

 sponges would offset any loss in actual 

 number of sponges taken during the 

 next year or two. 



c. The diving boats might have to bear a 

 small loss in revenue from the take of 

 sponges of less than 6 inches for a 3- 

 year period since they fish a much 

 larger area for their catch. 



d. The adoption of a 6-inch size limit 

 while sponge populations are increas- 

 ing would not affect actual income of 

 the sponge fishermen because of nor- 

 mally increasing landings. With ex- 

 pected increases in landing, the 5- 

 year period from 1959 onward seems 

 to be favorable for adopting this 

 recommendation. 



67 



