CONSERVATION OF SHELLFISH 



593 



em<xle 



hrood. 

 pouefc 



r-eleases 



" clam " or mussel was valuable in making pearl buttons. The 

 industry became so important that the number of adult clams was 

 rapidly depleted. Today, were it not for the work of Professor 

 Lefevre, Curtis, and 

 others, the fresh- 

 water mussel would 

 be practically ex- 

 terminated. But in 

 studying the life his- 

 tory of the mussel it 

 was found that one 

 stage is passed 

 attached to the gills 

 of certain fish. Now 

 the United States 

 Government raises 

 young mussels to the 

 free-swimming stage, 

 allows the larvae to 

 attach themselves to 

 the gills of the fish, and then releases the fish which later will 

 deposit the young mussels in localities favorable for their de- 

 velopment. 



Lobsters are being conserved by taking the fertilized eggs and 

 raising the young in hatcheries until they are large enough to care 

 for themselves. 



Practical Exercise 9. What methods are used to conserve shellfish in your 

 locality ? 



males "tJir-ovr 

 sp&rms into 

 water: Some 



drops to 

 "bottom, 

 becomes 

 adult. 



larva develops 

 ofcPffsh ' 



Life history of a fresh-water mussel. 



Self-Testing Exercise 



Fish should not be caught during the (1) season. Shell- 

 fish are killed by (2) . The freshwater mussel passes its 



larvae stage attached to the (3) of a (4). Many 



fishes spawn in (5) (6) (7) of our streams 



costs us millions of dollars a year in marketable fish. The supply of 



fish would soon be exhausted were it not for (8) (9). 



Caviar is prepared from the eggs of the (10). 



