324 ABSTRACTS: FISHERIES 



FISHERIES. — Studies on the reproduction and artificial propagation 

 of freshwater mussels. George Lefevre and Winterton C. 

 Curtis. Bulletin U. S. Bureau of Fisheries, 30: 105-202, pi. 

 vi-xvii, 4 text fig. 1910. 



The extended biological researches reported upon in this paper are 

 the basis upon which the U. S. Bureau of Fisheries, through its station 

 at Fairport, Iowa, is undertaking to propagate the commercially valuable 

 species of pearl mussels in the interests of the pearl button manufactur- 

 ing industry, which derives its raw materials from unionid shells found 

 in waters of the Mississippi basin. 



A large preliminary portion of the paper relates to the Unionidae 

 from the historical biological standpoint, but their mode of reproduc- 

 tion, structure, and the development and parasitism of the larvae are 

 naturally given chief and most detailed consideration and lead to an 

 extended account of the experiments and observations made for the 

 purpose of economic application of the facts. Messrs. Lefevre and 

 Curtis confirm previous investigators in their findings as to breeding 

 seasons of the Unionidae, the short and long periods of gravidity being 

 generic characters; and they also find the two well-marked types of 

 glochidia, those with hooks, which attach themselves chiefly to the fins 

 of fishes, and those without hooks, which are found in the gill filaments. 

 A third type, of ax-head shape, was also found in a few closely related 

 species. One genus, Strophitus, was found to develop without a parasitic 

 stage. 



As it proves upon experiment that the species of fish most satisfactory 

 as hosts for the larval mussels are the black basses and sunfishes so nu- 

 merous in Mississippi waters and collected yearly by the U. S. Bureau 

 of Fisheries in great quantities from the overflows, it was found com- 

 paratively easy to contrive means for wholesale infection of young fish 

 before distributing them for the regular fish-cultural purposes, and the 

 Fairport station at once entered upon such operations. But altho 

 the feasibility of mussel culture has been amply demonstrated, many 

 problems connected with it remain unsolved, and the investigators 

 expect to continue their researches with especial reference to conditions 

 of growth of the mussels, their food, enemies, diseases, and the very 

 interesting question of pearl formation. Ethel M. Smith. 



