[33] FISHERIES OF THE UNITED STATES. ' 



The beds along the entire coast are subject to nearly the same 

 vicissitudes of climate and other natural conditions, influencing the life 

 of the oysters, and as those viscissitudes are not peculiar to the Ameri- 

 can beds, nor to the moUuscan life alone, they do not require special 

 allusion. The number and character of the enemies and the extent of 

 their ravages depends ui:)on the locality. The manner in which the 

 work of such as belong to the mollusca is accomplished, has already been 

 described; but, in addition to the destructive effects of the various gas- 

 teropods and bivalves, the oysters, in common with several other shell- 

 tish, have to contend with other foes, belonging to other sub kingdoms. 

 Chief among these are the star-fishes, and the most prominent of that 

 destructive family is thQ Asterias forhesii^ ov " green" starfish. They 

 are descrilied and exhibited in the section of economic echinoderms, «S:c., 

 and specimens of oysters and star-fish, illustrating the method of attack 

 of the latter, are also exhibited in the molluscan collection. The man- 

 ner in which the oyster is eaten is described by Professor Yerrill, as 

 follows: 



"After bending their five flexible rays around the shell so as to i^artly 

 inclose it, they protrude the lobes and folds of their enormous saccular 

 stomach from the distended mouth, and surrounding the oyster shell 

 more or less comj)letely with the everted stomach they proceed to digest 

 the contents at leisure, and when the meal is finished they quietly with- 

 draw the stomach and stow it away in its proper place." 



The star fishes are very destruclive in Long Island Sound, but further 

 to the southward, and in Chesapeake Bay, do less damage. 



The several varieties of crabs, especially the Cancer irrora fits and Car- 

 cinus mccnas, destroy many oysters; usually the young are selected, as 

 they are more vulnerable than the mature animals; the damage by 

 crabs, however, is not nearly so great as that done hy the star fish, and 

 though the Chesapeake region suffers more from this enemy than the 

 northern shores, yet on account of the value of the crabs no steps can 

 or will be taken to lessen their numbers. Two species of fishes, the 

 "Sheepshead" {ArcJiosargiis prohatocephalus) and the "13rum" {Pogonias 

 chromis) are destructiN'e to oysters, the latter being especially so. Both 

 fishes are i^rovided with teeth with which they crush the young animals, 

 and both usually swallow them, shells and all. The Drum is the chief 

 depredator, but does not often trouble the beds north of Xew York. 

 On the New Jersey coast, however, it abounds, and moving in schools, 

 will frequently devastate thousands of dollars' worth of property. 



The minor enemies may be described as comi^rising all forms of ani- 

 mal life, such as the sponges, barnacles, annelids, and various shell-fish, 

 that by their presence on a bed deprive the oysters of food or room for 

 development, or, like the mussels, attract other more directly injurious 

 animals. 



The boring-sponge {Cliona sulji^nirca), and the red branching sponge 

 [Microciona prolifera) are the x^rincipal representatives of the Spongia. 

 228a 3 



