PEARLY FRESH-WATER MUSSELS 85 



SESSIONAL PAPER No. 38a 



It is noted that they had a very uneven inner surface, causing waste in cutting 

 blanks; the tips of the shells "were too thin for buttons. The colour and nacre were 

 not as bright as the usual run of the species found in the Mississippi river; but 

 it nevertheless makes a good button and, with proper care, the material could be 

 worked up with profit. As the Button Company of Trenton works up tons and tons 

 of these shells their statement as to the comparative value of the shells must also 

 receive due consideration. 



With regard to the propagation of the former species {Q. plicata), Dr. Howard, of 

 Fairport, Iowa, makes the following statement: — 



" Several factors favour the artificial propagation of this species upon a 

 practical scale. It is common and at present one of the most used shells in the 

 button industry. It seems to be a form not narrowly restricted as to hosts, and 

 these are indicated to be among the commonest and most readily obtainable 

 fishes. Although a river form, its habit as a dweller in stiller water and on 

 mud bottom makes it susceptible to propagation or control under conditions 

 readily imitable in artificial lakes or ponds. A continuous water supply is 

 desirable; my observation has been, however, that it will survive rather adverse 

 conditions in this respect. I have collected many live specimens from a slough 

 which had gone dry to the extent that only mud remained. Under these con- 

 ditions the majority of the pond mussels, Anodonta corpulenta, had died. I 

 would cite also the finding of this species accidentally introduced in the para- 

 sitic stage into an artificial pond at Fairport, Iowa. The pond had gone dry, 

 and I found a specimen still alive buried in mud barely moist. It is evident, I 

 think, from these observations that the species is hardy, at least as regards some 

 of the more common vicissitudes to which mussels are naturally subjected."^ 



In his experimental work with this species he found that P. annularis (crappie), 

 P. sparoides (speckled bass), P. flavescens (yellow perch), and L. pallidus (blue sun- 

 fish) were successful carriers. The spawning period is short, being confined chiefly to 

 the month of July. In the last fiscal year 147,000 glochidia of this species were set 

 free in the parasitic stage at Fairport. 



At present the safe-guarding of the beds against depletion is more urgent than 

 experimental work in artificial propagation of this species. As experience and equip- 

 ment are obtained, work on the more difficult Quadrulas should no doubt be pro- 

 ceeded with. 



I have so far not obtained any data of experimental work done on Q. undulata.. 

 In general appearance the two forms are similar. In plicata, the umbones are more 

 elevated and inflated than in undulata. 



PROTECTION OF FRESH-WATER MUSSELS. 



For the protection of the present mussel beds the following methods may be 

 considered of sufficient importance to merit discussion.^ 



(a) A closed season in each year. 



(&) Restriction as to the methods of fishing, 



(c) Restriction as to size of mussels retained by fishermen. 



{d) Closed regions for specified numlber of years. 



(e) The imposition of licenses. 



1 Experiments in propagation of Fresh Water Mussels of the Quadrula group. By Dr. A. 

 D. Howard, Bureau of Fisheries, Document No. 801. 



2 See also, Protection of Fresh Water Mussels, by R. E. Coker, Ph.D., Bureau of Fislier'.es, 

 Document No. 793. 



