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clear that if a natural oyster-bed, for example, be dredged 

 constantly and no time left for its reproduction, it will 

 amount to the same thing as if one repeatedly dredged 

 stones or other inert material that is the bottom would at 

 last be perfectly clear of them. 



Such an obvious argument as this needs no confirmation, 

 but if any such confirmation were needed, we might cite 

 what has occurred on the north-west coasts of Spain, where, 

 until the beginning of the present century, so great was the 

 quantity of oysters in the beds that they were sold at four 

 cuartos, or a little more than one penny per hundred, while 

 the present price averages 12 pesetas or qs. *jd. for the same 

 quantity. Even if we take into account the small con- 

 sumption at that time, owing to defective means of 

 communication, this circumstance is insufficient to explain 

 the enormous difference just mentioned, which points clearly 

 to the complete exhaustion of the beds. 



With regard to species which lead a more or less 

 migratory existence, there cannot be the least doubt that if 

 man had complete control over the area occupied by each, 

 the same principle of more fish being caught than could be 

 reproduced would lead to exhaustion likewise ; what has to 

 be determined is, how far man has such control in a given 

 locality. The old fishermen of the Mediterranean relate that 

 they remember having seen in their boyhood, species which 

 they do not see now, but we need not attach any great 

 importance to such a statement, until we have the means 

 of ascertaining whether the fish have gone out to deep 

 waters, but if there should be no communication between 

 two seas, and they were really exhausted under certain 

 conditions, this fact would of itself prove the theory of 

 exhaustion just propounded. The case is, however, different 

 with the ocean, the immensity of which makes extermination 



