REPORT OF THE COMMISSIONER OF FISHERIES. 93 
Two species of commercial mussels were handled in this work, the 
Lake Pepin mucket (Lampsilis Tuteola) and the river mucket 
(Lampsilis ligamentina), the last being propagated in only limited 
numbers. The infected fish were liberated in Lake Pokegama, Minn.. 
and in the Mississippi River at the following places: Lake Pepin, 
Minn. and Wis.; Minneiska, Minn.; Lynxville, Wis.: Fairport, 
Towa; New Boston, Ill.: and Lake Keokuk, Iowa and Ill. Opera- 
tions were not conducted in Arkansas as in previous years, owing to 
the impracticability of obtaining the necessary labor and equipment. 
The cost of mussel distribution, including overhead station expense, 
was $0.0581 per thousand, as compared with 80.0562 in 1920 and 
$0.0689 in 1919. 
Following is a detailed tabular statement of the number of larval 
mussels of each species deposited in the stated places: 
| | 
ee Ae | Lake Pepin | Mote 
Locality. Mucket. aildeae Total. 
Lake Pokegama, Minne...........04.--22-- nae: oy ee LAU el ae eT ae | 77,781,750 | 77,781,750 
pao Riv er at apa ch tage SRO OO ACEIS ES OEE ESE RABE Se eee | 44, 128, 800 +4, 128, 800 
ot aot geeecepe | 2,153, 000 
4,196,300 | 4, 446, 300 
14,300 14,300 
| 98158, 850 28, 158, 850 
| 13, 057, 050. | 13, 057, 050 
| 167,337,050 169, 740, 050 
| 
In order to supplement the efforts of the Bureau in increasing the 
supply of pearly mussels on which the pearl-button industry depends 
and to demonstrate the possibilities of mussel propagation in con- 
nection with the extensive operations in rescuing food fishes, the 
National Association of Button Manufacturers offered to cooperate 
with the Bureau by providing men to accompany each rescue crew 
on the upper river and to inoculate all fishes with the glochidia of 
the Lake Pepin mucket, the most important of the local mussels, 
Seven agents of the button manufacturers cooperated with seven 
crews working under the direction: of the superintendent of the 
Homer (Minn.) station, and during October and November inocu- 
lated nearly 6,000,000 fish with glochidia, estimated to number up- 
ward of 478,705,000. Material cooperation of this nature by an 
association of business men is a source of gratification to the Bureau 
as evidence of a cordial spirit and of faith in the practical value of 
the service rendered in the propagation of river mussels. 
RELATIONS WITH THE FISHERY INDUSTRIES. 
SUMMARY OF CONDITIONS AND ACTIVITIES, 
For several years the American fishing industry has been ex- 
periencing a critical condition to which various factors have con- 
tributed. During the Great War there was a universal demand for 
increased food production. to which the fisheries responded by pro- 
viding augmented facilities for capturing and handling fishery 
products, “Immediately following the war the demand for and the 
consumption of fish declined sharply at home and abroad, and an 
