FURTHER NOTES ON RAISING FRESHWATER 

 MUSSELS IN ENCLOSURES 



By Roy S. Corwin 



Scientific Assistant, U. S. Bureau of Fisheries 

 Homer, Minn. 



The results of experiments in propagating freshwater mus- 

 sels of the species Lampsilis luteola in Lake Pepin continue 

 to shed light on phases of the problem of raising these mol- 

 luscs in enclosures. From three experiments information has 

 been obtained which guides one in answering these questions : 

 (1) When do fishes infected in late summer or fall drop the 

 young mussels? (2) What is the average number of mus- 

 sels produced per fish from a single infection? (3) How 

 many mussels to the square foot can be raised in an en- 

 closure? 



LONG PARASITIC PERIOD IN LATE SUMMER INFECTIONS 



On August 19 and September 4, 1919, two lots of pike 

 perch, or so-called wall-eyed pike, were infected with the 

 glochidia of Lampsilis luteola and confined in enclosures. 



Of the first lot, infected August 19th, 5 were surviving 

 on October 24th, at which time they were carrying practically 

 the original infection. These fishes were marked with alumi- 

 num tags bearing numbers and were disposed of as follows : 

 Numbers 1, 3 and 5 were placed in a wire netting cage 10 

 feet square and 4 feet high, and submerged in the lake in 

 12 feet of water; and numbers 2 and 4 were taken to the 

 Bureau of Fisheries station at Homer, Minn., and kept for 

 examination in a tank of running water. 



Of the second lot, infected September 4th, 8 were alive 

 on October 24th and carrying apparently an undiminished 

 number of glochidia. These fishes were also marked with 

 tags and separated. Numbers 6, 7, 8, 9 and 10 being placed in 



