FISHES It has been the boast of Worcestershire that all the different kinds of EngUsh freshwater fish are to be found in one or other of the rivers in the county. There is more truth in this than in most of such generali- zations, as the county is situate in the Severn and Trent watersheds. With one or two exceptions nearly all the different species of freshwater fish occur in the Severn and its tributaries, even if not in its Worcester- shire tributaries ; so it is possible, but most improbable, from their present condition that such of the English freshwater fish that are not found in the Severn watershed may be found in the Worcestershire streams that are the upper waters of some of the tributaries of the Trent. Broadly speaking, for the purpose of the distribution of freshwater fish in England and Wales, a Hne representing the oolitic rocks running from Portland to the Humber divides the country into salmon rivers and coarse fish rivers ; all east of the line being coarse fish, west of it salmon. It is not to be understood that no salmon are found to the east of the line, or coarse fish to the west, but that the eastern rivers are those suited for coarse fish, and were probably the original home of those fish, while the western rivers were the original home of the Salmonidce, and salmon east of the line are mere survivals of a past state of things, while coarse fish west of the line are immigrants. One of the interesting points as to Worcestershire fish is the probability that originally there were no coarse fish in its rivers, but that through its tributary the Avon the immigration of coarse fish began. The date of this immigration it is perhaps im- possible to fix, but it was no doubt aided and increased by the canals made during the last half of the eighteenth and the first quarter of the nineteenth centuries. In considering the Worcestershire fish the two divi- sions must be borne in mind, the original inhabitants and the immigrants, and these are broadly represented by the Salmonidee and the Cyprinidce. Another great division of the Worcestershire fish, that is the Severn fish, is with regard to the place of breeding ; several of the more important kinds are what are known as anadromous fish, that is they go up the rivers to spawn. These include the salmon {Salmo salar), the different forms of trout (S. trutta), the two species of shad, the allice {Clupea alosd) and the twaite {C. fintd) ; and the two species of lamprey, the great sea lamprey [Petromyzon marinus) and the lampern (P. jiuviatilus) . The catadromous fish, those that descend from the rivers to breed in the sea, are represented only by the eel {Anguilla vulgaris), for although certain other forms drop down the rivers at different times of the year they do not appear to do so for breeding. In order to keep up the stock of these two great divisions, the anadromous and catadromous, one thing is necessary : that their passage up 131
