1242 OYSTERS, AND ALL ABOUT THEM. 



The opportunity of observing the natural formation of 

 a new oyster bed is rare, but the details of the process 

 have been carefully watched in at least one case. Up to 

 the year 1825, the Limfjord in Northern Jutland consisted 

 of a series of brackish water lakes communicating with one 

 another, and opening on the east into the Kattegat. In 

 the last century, unsuccessful attempts were made to plant 

 them with oysters. But, on the 3rd of February, 1825, a 

 great storm broke through the dam which separated the 

 western part of the Limfjord from the North Sea ; in 

 consequence of this, the water of the fjord became 

 gradually salter, the brackish water plants and animals 

 disappeared and North Sea animals took their places. 

 Among these, in 1851, oysters were observed, and, year by 

 year, they extended over a larger area. In 1860, only 

 150,000 were taken; at present, there are ninety-eight 

 beds, and, in 1871-1872, 7,000,000 of full-grown oysters 

 were exported. There could have been very few oysters 

 before 1851, when the first were noticed. But supposing 

 the first entered as early as 1 840, then, in thirty years, they 

 spread themselves over an area of about sixty-four English 

 miles, so that every year, on the average, they advanced 

 more than two miles. The oyster beds are, at present, 

 three-fifths of a mile to five miles apart, so that the larvae 

 must have been able to wander for at least five miles. x 



During this slow process of immigration, it is obvious 

 that the enemies and the competitors of the oysters had 

 just as good a chance as the oysters themselves ; and yet 

 the latter have established themselves with great success. 

 Why should they be unable to do the like elsewhere ? 



I must confess myself unable to arrive at a conclusion 

 on the question whether what is called " overdredging" 



1 Mobius. Die Aiuter und die Austern-ivirthschaft, p. 52. 



