154 



BULLETIN OF THE BUREAU OF FISHERIES. 



Tablb 20. — Number op Species op Commerciai, Mussels Known to be Carried as Parasites 



BY Certain Fishes. 



Fishes. 



Scientific name. 



Common name. 



Total. 



Ameiurus melas 



Ameiurus nebulosus 



Anguilla chrysypa 



Aplodinotus gninniens 



Dorosoma cepediannm 



Esox ludus 



Eupomotis gibbosus 



Ictalurus punctatus 



Lepisosteus osseus 



Lepisosteus platostomus 



Lepisosteus tristcechus 



Lepomis cyanellus 



Lepomis euryorus 



Lepomis hmnilis 



Lepomis pallidas 



Leptops olivaris 



Micropterus dolomieu 



Micropterus salmoides 



Necturus maculosus °. 



Pomolobus chrysochloris 



Perca flavesccns 



Pomoxis annularis 



Pomoxis sparoides 



Roccus chrysops 



Scaphirhynchus platorhynchus. , 



Schilbeodes gyrinus 



Stizostedion canadense 



Stizostedion vitreum 



Bullhead 



do 



Eel 



Sheepshead 



Gizzard shad 



Pike 



Red-ear sunfish 



Spotted cat 



Long-nosed gar 



Short-nosed gar 



Alligator gar 



Blue-spotted sunfish 



Sunfish 



Orange-spotted sunfish. , 



Bluegill 



Yellow cat 



Smallmouth black bass. . 

 Largemouth black bass. 



Mud puppy 



River herring 



Yellow perch 



White crappie 



Black crappie 



Striped bass 



Sand sturgeon 



Mad Tom 



Sanger 



Wall-eye 



(?) 



(?) 



o An amphibian. 



It is necessary to point to some significant practical conclusions from the data pre- 

 sented. Since mussels are "choice" as to their hosts, the qjiances for the successful 

 attachment of glochidia in nature are greatly diminished. The glochidia when dis- 

 charged from a parent mussel are lost if no fish are at hand to receive them or if the 

 fish that pass are not of one of the very limited number of spgcies which are useful to 

 the glochidia of that particular mussel. 



There must necessarily be some definite ecologic relation between the mussel and 

 the fish. The bottom that is inhabited by the hickory-nut mussel must be one that is 

 frequented by the sand sturgeon during the breeding season of that mussel. Again, if 

 one were looking for the river herring, it would be reasonable to expect to find them, 

 during June at least, in places where niggerhead beds are known to exist. It is evi- 

 dent that no species of mussel could exist unless its host were of such habit as to be at 

 the right places at the right times in a sufficient number of cases to permit first, of the 

 infection occurring, and second, of the young dropping where they can sur\4ve. 



What the factors are that bring mussels and fish into proper association we can not 

 say. In the case of one species of mussel (the pocketbook) at least, it is known that' the 

 gravid mussel protrudes from its shell a portion of its mantle as a long brightly marked 

 flap that waves in the water, assuming the appearance of an insect larva or other at- 

 tractive bait (p. 85). Again we have the sheepshead fish (fresh-water drum) which is 

 known to feed upon small mollusks, mussels, and the sphseriids and univalves that live 

 on mussel beds, and which thus exposes itself to easy infection; sheepshead, indeed, are 

 almost invariably found to be loaded with glochidia. The behavior of the pocketbook 

 is believed to be exceptional, and the sheepshead is one of a very few species of fish 



