RAISING FRESHWATER MUSSELS IN ENCLOSURES. 



By Roy S. Corwin, 

 Scientific Assistant, U. S. Bureau of Fisheries. 



Results of artificial infections of Lampsilis luteola on the gills 

 of several species of game fishes, confined in enclosures in Lake 

 Pepin, are throwing considerable light upon the problem of com- 

 mercial propagation of fresh- water mussels for button purposes. 

 Experiments begun in May, 1918, and continued up to the present, 

 have been particularly instructive. 



In order to make a quantitative test of methods of artificial 

 propagation, enclosures or pens were constructed with board 

 bottoms and sides of one inch mesh wire netting. The bottoms 

 of the pens were covered to the depth of about one inch with sand 

 taken from the shore above the water line. The pens were then 

 submerged in water about five feet deep. Three localities in 

 Lake Pepin were used: Lake City and Frontenac, Minnesota, 

 and Stockholm, Wisconsin. A brief summary of the operations 

 and findings in connection with several of the enclosures follows. 



Lake City Enclosure 



Five lots of fishes, consisting of wall-eyed pike, sauger, small- 

 mouthed black bass, white bass, yellow perch, sunfish and crappie, 

 infected with the glochidia of Lampsilis luteola, on dates extend- 

 ing from May 16th, 1918, to July 3rd, 1918, were confined in 

 the Lake City enclosure. This enclosure was 12 feet square and 

 had sides from 6 to 12 feet in height. After deducting the number 

 of fishes which died and those which either escaped from the pen 

 or were caught out by fishing parties, it was found that 79 fishes 

 had remained alive in the enclosure long enough to drop the young 

 mussels. 



From this enclosure on September 23rd, 1918, after a maximum 

 of 130 days from the date of the first infection, were removed 

 11,199 live juvenile L. luteola, ranging in size from 16.0 millimeters 

 to 3.0 millimeters. On previous dates 395 live juvenile luteola 

 had been removed, making a total of 11,594 from the pen. To 

 this might also be added 1000 pairs of valves of dead juvenile 

 luteolas, making a grand total of 12,594. 



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