Convin. — Raising Freshwater Mussels 311 



ners and against the sides of the enclosure, whence they could 

 be removed in numbers from 22 to 50 to each shovelful of 

 approximately one square foot of the sand and mud from the 

 bottom. From the middle of the area few, if any, mussels 

 were taken. Eight pairs of valves of luteola which had suc- 

 cumbed before their second year were found, leaving 107 

 of the original 1,060 not definitely accounted for. 



How many second season Lampsilis luteola to the square 

 foot will live and grow during the third year of their ex- 

 istence? The present highest record is 8.94 to the square 

 foot, obtained when 447 second season luteola of the 461 

 replanted, passed their third year in a space 10 feet long 

 and 5 feet wide, increasing in average length from 19.1 to 41.6 

 millimeters. Seven pairs of valves of dead second season 

 luteola were found, leaving 7 of the original 461 whose dis- 

 appearance cannot be explained. 



SUMMARY 



1. Pike perch, infected as late in the summer as August 

 19th, carry glochidia until the following May. 



2. The average number of living juvenile Lampsilis 

 luteola produced by one pike perch from a single infection is 

 at least 833. The use of more finely meshed enclosures may 

 raise this figure. 



3. Eighteen first season mussels to the square foot will 

 thrive in an enclosure during their second year; and 8 second 

 season mussels to the square foot will flourish during their 

 third year. Further investigations may show that a more 

 dense population would not be detrimental to the growth of 

 the mussels. 



