4o8 A HISTORY OF FISHES 



be of practical use, the main problems whose solution wc seek 

 may be said to be two — the rational and economical exploita- 

 tion of the fisheries, and the prognostication of good and bad 

 years." As far as the second of these problems is concerned, 

 science has for some time been able to form a pretty good idea 

 of the probable success or failure of a particular fishery during 

 the next year or two, and a stage has now been reached when 

 actual and accurate prophecy is possible. That stocks of fish 

 do vary considerably from year to year, quite independent of 

 the amount of fishing, has been known for some time, and it 

 will clearly be of the greatest practical importance to the 

 industry when the factors that govern these fluctuations are 

 thoroughly understood. Finally, there is room for a good deal 

 of research on the types of gear used in fishing, and on such 

 subsidiary branches of the industry as the handhng of fish, 

 refrigeration, preservation, packing, etc. 



The maintenance or improvement of the stocks of certain 

 species of edible fish by some form of pisciculture is a very 

 ancient practice, and it is known that in classical times the 

 Greeks and Romans made a habit of cultivating fishes in 

 captivity for the table, and of stocking their lakes and ponds 

 with ova or young fish obtained from other locaHties. Two 

 main types of modern pisciculture may be recognised: (i) the 

 rearing of fishes in confinement until they are large enough to 

 be eaten, and (2) the stocking of waters with eggs or fry obtained 

 froni fishes breeding in captivity. The ancient Romans certainly 

 carried on the first method, and were in the habit of admitting 

 young fishes from the sea into special enclosures or vivaria 

 by means of sluices, and then fattening them up for the table. 

 Exactly similar cultivation of marine fishes is carried out at 

 the present day in the lagoons of the Adriatic and the salt 

 niarshes of various parts of France. The number of diflferent 

 kinds of fish which can be reared from the tgg to maturity in 

 captivity is very small indeed, the best-known examples among 

 fresh-water forms being the famihar Goldfish, and the Httle 

 Top Minnows or Cyprinodonts so popular with aquarium lovers. 

 The Carp, Crucian Carp, Tench, Orfe, Ide, Bream, Roach, 

 Dace, Trout, Pike, Eel, and Perch are all cultivated to a greater 

 or lesser extent by fish culturists of Europe, but only the Carp 

 lends itself to domestication to an extent which makes it a 

 commercial proposition. This is the principal fish used in 

 pond culture throughout the world, and in Central and Southern 

 Europe, as well as in China and other oriental countries, Carp 



