DIFFERENT WAYS OF SWIMMING 



conditions; they multiply, cover the bottom, pervade 

 the submerged foliage. There, more easily than in 

 the sea near by, they find conditions suited to their 

 development; they grow more rapidly, multiply more 

 profusely. This lake is not only a place of refuge, a 

 shelter, broad and undisturbed; it is essentially fertile, 

 made so by the water which fills it, and endowed with 

 an extreme capacity for the production of life, and the 

 fishing industry is not slow to take full advantage of 

 the fact. 



The Gulf of Gabes, an exception to the general rule 

 in the Mediterranean, has a perceptible tide. Twice 

 every day the water rises and falls again. In the lake 

 these movements appear as currents running in and 

 out which renew the water regularly and prevent 

 stagnation. Water from the gulf enters the lake 

 when the tide is high; the water of the lake runs 

 out into the gulf at the ebb, when the level is lower. 

 These currents, coming and going alternately, pass 

 through the narrow passes or gates which connect the 

 lake with the sea. With absolute regularity, these 

 passes are crossed successively by the entering current 

 and by the leaving current. The fish respond to these 

 tidal impulses. Always inclined to move against the 

 current, the fish from the sea enter the lake when the 

 ebb leaves it and, conversely, those from the lake try 

 to go to the sea when the tide rises. So there is a 

 ceaseless alternation of comings and goings which, 

 each time, carry along hundreds and thousands of 

 fish. 



This double impulse has determined the method 

 of fishing. The passes have been barred by fixed nets 

 made of wattle or metal webbing, and placed in such 

 a way as to permit free entry to the lake, but not 

 exit from it. In this manner the lake has been turned 

 into a huge natural trap, with a superficial area of 

 some hundreds of square miles, into which the fish 

 from the sea come successively, and are compelled to 



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