86 BULLETIN OF THE BUREAU OF FISHERIES. 



PLANTING. 



The planting of mussels in nature by dropping from the host fish, although conceiv- 

 ably controlled to a certain extent by natural factors favorable to the mussel (Howard, 

 1914a, p. 39), is doubtless for the most part a haphazard process. Those which fall on 

 unfavorable bottom must perish, and there is every reason to believe that successful 

 mussel beds are the results of a precise combination of conditions at a given place. The 

 investigations on sea clams and oysters show that myriads of the young develop to a 

 given stage only to die if they are not on a suitable bottom. Great accumulations of 

 these young clams on unsuitable ground may be saved by transplanting. When so 

 employed in cultural operations, they are designated as seed clams. 



In the case of fresh-water mussels an artificial planting likewise would doubtless be 

 more economical of mussels — at least than the planting in nature by fish allowed to go 

 at large. In restocking either privately controlled or publicly owned waters the general 

 procedure that suggests itself is to rear the young mussels to an age of 2 or 3 months 

 or more and then to release them on bottoms that are known to be favorable. 



COMMERCIAL POSSIBILITIES. 



If the natural supply is not maintained by the means described and the price of 

 shells continues to advance, there will possibly come a time when the rearing of mussels 

 by a complete system of culture will become commercially profitable for individuals 

 and privately owned corporations, whereas now carried out only by Government 

 agencies. 9 



A few experiments have been made to test the palatability of fresh-water mussels. 

 Incomplete and inexhaustive as these tests have been they have yielded encouraging if 

 not completely satisfactory results. Reports of edible species have been received. 

 The use of the mussel for food in addition to the present use of the shell alone would 

 aid greatly in making the culture of mussels commercially profitable. The successful 

 culture of the marine mother-of-pearl shell (Margaratifera var. maxatlantica) has been 

 described by Dr. C. H. Townsend (1916). Seflor Gaston J. Vives, on Espiritu Santo 

 Island, in the Gulf of California, reared these shells on a scale commercially profitable. 



The development of an industry of this nature in the culture of fresh-water mussels 

 might be dependent upon the acquirement of property rights on river bottoms suitable 

 for rearing mussels. Precedents for such allotments of water-covered areas are familiar 

 in the leases for oyster beds on our sea coasts. However, the experiments thus far 

 carried out indicate that the culture of mussels may differ to this extent from that com- 

 monly employed in America ln for edible oysters, in that mussels can more conveniently 

 be grown in crates or containers of some sort rather than on open bottom. This is true 

 at least because of the potential migratory nature of the mussel as compared with the 

 sessile habit of the oyster; i. e., it is necessary in the former case to provide for a possible 

 loss of a plant by migration. However, that the recovery of fresh-water mussels may be 

 comparatively easy under some conditions is the testimony of Prof. Isely (19 14). He 



9 The possible alternative is the practical extermination of the mussel through excessive fishing either for the mussel itself 

 or its host fish, or both. There have been well-known examples in history of complete extermination of useful species. 



10 In the more intensive cultivation of oysters and clams in Europe containers called ponds, which are in thenatureof sluice- 

 ways through which flowing water is conducted, have been extensively employed. 



