WHAT THE DORADO IS. 
117 
excellent salad which is made out of the head. 
From what has been said, it will easily be 
understood that little is known of this gallant 
fish’s habits. It is probable that his original 
home is the tropics. Dr. Gunther in his Study 
of Fishes says that many tropical fishes have 
followed the river system of the Plate far down 
into the Temperate Region, and if anyone looks 
at the map he will see that this was bound to 
happen. The Plate itself, the Rio de la Plata, 
the Silver River of the old conquistadores, is 
really an estuary, like our Humber on a larger 
scale : and just as the Humber is formed by the 
Trent and the Ouse, so the Plate is formed by 
the Parang and Uruguay. The Parana, with 
its great sister the Paraguay, and many other 
tributaries, rises far north in the tropic, and 
between them they drain a large part of South 
America below the Line. The dorado, there¬ 
fore, that bold, free-swimming and masterful 
fish, finds himself placed in a waterway system 
measuring over fifteen hundred miles from 
north to south, and rather more at its greatest 
breadth, and it is only natural that he should 
travel up and down at his pleasure, driven by 
search of food, or by temperature, or by mating 
instinct. 1 But whether his movements are 
1 In order to migrate up and down the Parand he would 
have to pass the Falls of Guayra. Having seen them in low 
water, I judge this to be not quite impossible during the long 
periods of high water caused by the rainy season in the 
tropics. 
