Vol. XXIV, No. 3 



WASHINGTON 



March, 1913 



c> 



TME 



ATEOHAIL 



©(SJIAIPIHIILC 



MBAM] 



OYSTERS: THE W^ORLD'S MOST VALUABLE 



WATER CROP 



By Hugh M. Smith 



U. S. Deputy Commissioner of Fisheries 



Author of "Making the Fur Seal Abundant," "Federal Fish Farming," "Our Fish 

 Immigrants," "America's Most Valuable Fishes," "The Pearl Fisheries of 

 Ceylon," "King Herring," "Some Great Fishes of the Sea," "Brittany, the 

 Land of the Sardine," etc., in the National Geographic Magazine. 



OYSTERS are the most popular 

 and most extensively eaten of 

 all shellfish ; economically, they 

 are the most important of all cultivated 

 water products and, with the single ex- 

 ception of the sea herrings, the most 

 valuable of all aquatic animals. Zoolog- 

 ically considered, oysters are lamelli- 

 branchiate mollusks of the genus Ostrea. 



In at least 35 countries oysters support 

 a special fishery, and in various other 

 countries enter into the food supply. On 

 the shores of all the temperate and tropi- 

 cal oceans and seas, oysters occur in 

 greater or less abundance ; but the supply 

 in the North Atlantic exceeds that of all 

 the other waters combined. Not less than 

 150,000 men and women are engaged in 

 the oyster industry ; and the capital in- 

 vested in vessels, boats, apparatus, oyster 

 lands, and cultural establishments aggre- 

 gates many million dollars. 



The oyster crop of the world at the 

 present time amounts to over 42 million 

 bushels and is valued at nearly $25,000,- 

 000. Of this output, the share of the 

 United States is 88 per cent of the quan- 

 tity and 69 per cent of the value. Of 

 the remaining portion, fully 65 per cent 

 of the quantity and 50 per cent of the 

 value belong to France. 



At least 100 species are known, with a 

 rather wide range in size, shape, habits, 

 flavor, and food value. Some excellent 

 species exist in the equatorial and sub- 

 tropical regions, but the best occur in 

 temperate climes. The northern limits 

 of their habitat are the Gulf of St. Law- 

 rence and southern Norway in the At- 

 lantic, and Hokkaido and Puget Sound 

 in the Pacific. 



Oysters produce an immense number 

 of young in order to compensate for the 

 heavy mortality that occurs at all stages 

 of growth, but particularly in the early 

 months. It is an astonishing biological 

 fact that in some species of x)yster each 

 sex is represented by a dififerent indi- 

 vidual, as in the oyster of the Atlantic 

 coast of North America : while in other 

 species both sexes are united in one in- 

 dividual — the male stage alternating with 

 the female, as in the common oyster of 

 the Atlantic coast of Europe. 



After the oyster attains a size that is 

 visible to the unaided eye, it is incapable 

 of changing its position. This is in 

 marked contrast with the newly born 

 young, which is a free-swimming crea- 

 ture, floating about with tides and cur- 

 rents, and quite as likely to settle down 

 on a far-distant bank or bar as to rejoin 

 its progenitors. 



