THE HABITS ATSD HAUNTS OF FISH. 17 



of the above streams, owing to the rapid fall in most 

 cases, and the purity and cool temperature of their 

 waters, were the annual resort of salmon and other 

 migratory fish in immense numbers a few generations 

 back. What do we find to be the case to-day? The 

 salmon are debarred from ascending even the main river, 

 except during heavy floods, by senselessly contrived weirs 

 at different points, and with the same exception, the pas- 

 sage up the Derwent is entirely shut off by weirs below 

 Derby. In respect to the Dove, being swift and of ex- 

 cessively rapid fall, it was originally the favorite resort of 

 Trent salmon, many of which would ascend as high as 

 Dovedale. There are some four or five weirs that are 

 rendered passable only when the river is bank-full, after 

 a very heavy shoot of water from the hills, until Rocester 

 is reached, where there is situated a weir that is impass- 

 able at all times from its peculiar construction. All this 

 may seem strange to those of our readers who have been 

 led to imagine that the natural buoyancy and strength of 

 anadromous fish enable them to overcome both ordinary 

 and extraordinary difficulties in the way of impediments 

 to their upward course. It is, nevertheless, the fact that 

 salmon are to be annually seen for weeks and even months 

 vainly trying to ascend an obstruction, known to be an 

 effectual bar to their upward progress, until finally they 

 deposit their spawn at the point where the passage is ar- 

 rested, whether suitable or not. Salmon leap to a great 

 height to surmount a cascade or perpendicular fall, but 

 the long slanting weirs are not to be stemmed when they 

 exceed a given length and angle. 



But to return. The Tame is now polluted to such an 

 extent that even pike fail of late to flourish in it. The 

 main river, too, is now also polluted so as to admit only 

 of the presence of fresh run migratory fish when flooded 

 by its tributaries. Thus, out of five hundred and seventy- 

 five miles of water only a very few can be accessible to the 



