THE FAIRPORT FISHERIES BIOLOGICAL STATION. 399 



for the study of the development of lake conditions and of the effect of such conditions 

 upon the abundance of commercial fishes. As far as its means permit, the Bureau has 

 already availed itself of these advantages for studies of the movement of fishes and of 

 the effect of the new conditions upon the supply of fish food and the development of 

 fishery resources. A good deal of valuable data has already been secured. 



The favorable features of location and environment which have been described 

 under the heads of "Grounds" and "Biological environment" are some of those which 

 dictated the establishment of the station at Fairport. 



MUSSEL PROPAGATION. BY EXPERIMENT AND PRACTICE. 



ORCVNIZ.^TION AND GENERAL PLAN. 



In the practical propagation of mussels the Fairport station serves as headquarters 

 for field operations conducted throughout the Mississippi Basin, including the Mississippi 

 River and its various tributaries. There may be in the field at one time from two to six 

 field parties operating near the station or at distances of several hundred miles, and all 

 parties are organized under the superintendent of fish culture. 



While the available personnel and means do not permit of covering the extensive 

 field, the present endeavor is to restrict the operations to certain localities favorable for 

 the work and needing of replenishment, and to distribute these localities as widely as 

 practicable through the territory. Hence operations are now conducted in Lake Pepin 

 of Minnesota and Wisconsin, on the Mississippi at Fairport, Iowa, on the Wabash in 

 Indiana, and on the White and Black Rivers of Arkansas. 



Each field party is under the direction of a competent head, who may be a perma- 

 nent or temporary employee, sent out from the Fairport station or from the central 

 office in Washington to work under the direction of the Fairport station. The crews 

 employed in the seining of fishes, inoculating them with glochidia, and liberating them 

 again in the river are made up of local laborers or fishermen temporarily employed. 



There is no definite outlay of apparatus required. The chief of the party is pro- 

 vided with a compound microscope or a dissecting microscope, an ordinary Coddington 

 magnifier, the usual dissecting instruments, and a field equipment which may consist 

 of seines, fyke nets, tubs, tanks, buckets, etc. A Government-owned launch and row- 

 boats may be used or launch and rowboats may be employed in the region where the 

 operations are conducted. It is generally convenient to use flat-bottom rowboats of 

 small size, 16 to 24 feet in length, but a launch is also practically necessary in order 

 that more rapid movements can be made from place to place, thus extending the sphere 

 of operations possible for a day's work. In some cases the field parties can find accom- 

 modation in towns conveniently situated, but in other cases a house-boat must be 

 rented in order that the fishing party may have a place in which to sleep and board. 



The methods of propagation are based upon a peculiar feature of the normal course 

 of development of fresh-water mussels. The very young fresh-water mussels, with rare 

 exception, when first liberated from the incubation pouches of the parent, must become 

 parasitic upon fish in order to pass through the next stage of their existence. To this 

 end, if the chance offers after liberation, the young mussels, or glochidia, as they are 

 called in this stage, attach themselves to the gills, fins, or scales of a fish. The mussels 

 of economic importance attach themselves almost exclusively to the gills. In attaching 

 or biting on the fish a very slight wound seems to be caused, which begins at once to 



