Reuling. — Experiments in Rearing Fresh-water Mussels 155 



The results during the past season have been still more gratify- 

 ing. Young luteola were obtained in each of five troughs planted 

 with this species. In one trough 2008 were counted at the end 

 of the season. These little mussels varied in length from 9 mm. 

 to 17.5 mm. The growth comparing very favorably with that 

 made by the young of this species in their natural habitat. In one 

 trough devoted to the river mucket, L. ligamentina, a total of 

 565 were reared. These little mussels varied in length from 5 mm. 

 to 8.5 mm. In one trough planted with the yellow sand-shell, a 

 count of 2006 was obtained at the end of the season, the young 

 mussels varying in length from 5.5 mm. to 12 mm. The result of 

 this experiment is highly interesting, in that it is the first record of 

 the artificial rearing of this very valuable species in any quantity. 



The 746 young luteola reared during the summer of 1918 were 

 carried over the winter in a shallow crate bottom five feet square 

 and eight inches deep, submerged in one of the earth ponds. 

 During the summer an inventory of the crate bottom gave a 

 count of 285 young mussels, a survival percentage of about 38 

 per cent. 



The method of artificial rearing of young mussels as detailed 

 above, denotes a distinct departure from the methods previously 

 used, and gives the operator quite complete control of conditions 

 throughout. The results have been such as to justify the con- 

 tinuance of the method on a much larger scale another season and 

 plans are under way for materially increasing the facilities and 

 equipment. Certain phases of the work, however, need further 

 study and amplification. Additional information on the possible 

 enemies of the young mussels in the troughs is needed; a study 

 of their food should be made; and further experiments should be 

 made to determine the most favorable bottom material for the 

 troughs, whether fine sand alone, or sand with a slight admixture of 

 silt, etc. Present indications are that fine sand is the most 

 desirable bottom material. 



