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How do Starfishes open Oysters? 



# 



By 

 Dr. Paulus Schiemenz. 



Many inhabitants of the sea know as well as men do that oysters are 

 good to eat, and the destruction which they suffer on this account can 

 scarcely be less than that brought about by human agency. Starfishes 

 especially extirpate them in great numbers, and Mobiusf maintains that 

 they are the most pernicious enemies which the oyster possesses, 

 although, on the other hand, people have not been wanting who held 

 the destruction of oysters by starfishes to be a fable, ^i 



Collins II calculates the damage done by these voracious robbers on 

 the oyster beds of Connecticut alone for the years 1887, 1888, and 1889, 

 at 463,G00, 613,500, and 412,250 dollars, whilst that done in all other 

 ways, by molluscs, mud, frost, etc., only represented a total of 39,200, 

 46,750, and 52,450 dollars. 



In view of this enormous injury caused by starfishes to the oyster 

 beds, it will be worth while to endeavour to obtain a clear idea of how 

 a starfish really succeeds in eating an oyster. It is generally known 

 that bivalve molluscs, and amongst them oysters, can close their shells 

 so tightly against enemies that considerable force is necessary to open 

 them, and the question arises, Is a starfish able to exert that force ? 



For the purposes of our discussion, we shall divide the starfishes 

 which attack molluscs into two groups. Those of the first group have 



* Mitthcilungcn des Deutschen See/ischereivereins. Bd. xii. No. 6, 1896. Translated 

 from the German by E. J. Allen. 



My thanks are due to Professor Dr. Henking, the general secretary of the German 

 Sea Fisheries Association, both for permission to publish the translation of tliis article, and 

 also for the loan of the blocks from which the figures arc printed. E. J. A. 



t MoBius, K. " Ueber die Thiere der schleswig-holsteinischen Austerbanke, ihre 

 physikalischen und biologischen Lebensverhaltnisse. " Sitz.-Ber. Akad. Berlin. 1893, 

 pp. 67-92. 



X Fischer, P. "Faune conchyliogiquo marine du departeraent de la Gironde." Act. 

 Soc. Linn. Bordeaux. Tome 25, 1864, pp. 257-344. 



II Collins, J. W., "Notes on the oyster fishery of Connecticut." Bull. U.S. Fish. 

 Comm., vol ix. pp. 461-497, 1891. 



