NA TURE 



i6 



THURSDAY, DECEMBER 8, 1910. 



FRESH-WATER FISH-CULTVRE IN FRANCE. 



Eticvclopedie agricole. Pisciculture. By Georges 

 Gu^naux. Introduction by Dr. P. Regnard. Pre- 

 face by M. Charles Deloncle. Pp. xii + 489. (Paris : 

 Bailliere et Fils.) Price 5 francs. 



THIS is a comprehensive, compact, and eminently 

 practical handbook on all matters relating to 

 fresh-water pisciculture. Much of the information 

 and criticism which it contains applies almost equally 

 to England as to France, since most of the fishes dealt 

 with are found in our islands, and the almost 

 complete neglect of fresh-water pisciculture— 

 except in the case of the Salmonidae — is as 

 characteristic of this country as of that. What 

 is true of the depopulation of the French 

 watercourses is partly true of our own. In France the 

 depqjulation and its neglect were due partly to obvious 

 causes inseparable from industrial progress, such as 

 the opening of canals, the development of navigation, 

 and the establishment of manufacturing works and 

 chemical factories on the river banks, and partly to 

 lack of enthusiasm following on historical events. 

 The means adopted to arrest the depopulation, much 

 less to restock the waters, have been, and continue to 

 be, utterly disproportionate to the extent of the waters 

 and to the magnitude of the task. 



The results of this neglect are : — (i) That France 

 consumes extremely little fresh-water fish, either abso- 

 lutely, or relatively to the consumption of marine 

 species; and (2) that the great bulk of what little she 

 does consume is derived from adjacent countries, prin- 

 cipally Germany, where the rearing of carp especially 

 has been developed into a paying industry by long 

 years of experience and the application of scientific 

 methods. While- it is possible, as hinted by the 

 author, that a protective tariff might do a little to 

 obviate this unsatisfactory state of affairs, the only 

 complete solution of the problem is for France to grow 

 her own fish. These French watercourses (our own 

 rivers and broads also to some extent) are capable of 

 producing an abundance of highly nutritious food. In 

 both countries there are numerous fresh-water species 

 the chair e of which, M. Guenaux assures us, is excel- 

 IcHte, and would form a pleasing variant to the 

 marine species which at present more or less 

 flood the fish markets and almost exclusively appear 

 on our tables. Clearly something should be done to 

 develop this branch of food production, and to some 

 extent M. Guenaux's practical text-book points the 

 way. 



But although fresh-water fish-culture is in the main 

 neglected in France, there are a few salmon- and 

 trout-hatching establishments, which seem to cost verj- 

 little and pay remarkably well ; also several labora- 

 tories connected with schools of agriculture, which con- 

 tribute to the repopulation of the waters. Finally, 

 attached to the Universities of Grenoble, Clermont- 

 Ferrand, Toulouse, and Dijon are scientific labora- 

 tories for the study of fresh-water biology which 

 pursue a double aim, scientific and practical. The 

 NO. 2145, VOL. 85] 



University of Toulouse in particular has a large in- 

 stitution, started in 1903, devoted entirely to fresh- 

 water pisciculture and hydrobiology, with museums, 

 aquarium, and laboratories. In this matter England 

 has something to learn from France, since, to the 

 best of the reviewer's knowledge, the only station 

 devoted to fresh-water hydrobiology in this country is 

 a small private one on a Norfolk broad. 



In writing a book on the whole subject it has been 

 necessary for its author to combine the knowledge and 

 qualities of a naturalist with those of an engineer and 

 "practical man." This unusual demand on one's 

 capacity and versatility has been met by M. Guenaux 

 with conspicuous success. A critical inspection of the 

 text of this book shows that its author is almost 

 equally familiar with the morphological character- 

 istics, taxonomic relations, and bionomical reactions 

 (including feeding and spawning habits and require- 

 ments) of each species of fresh-water fish as he is 

 with the merits and demerits of different kinds of 

 salmon ladders, or the latest devices connected with 

 egg-hatching apparatus, while he is evidently 

 thoroughly an fait with the French laws relating to 

 fresh-water fisheries, the weaknesses of which legisla- 

 tion he criticises in a characteristically practical 

 manner. 



The book opens with a brief account of the general 

 anatomy of fishes, proceeding to take up each group 

 in its natural order, explaining their taxonomic rela- 

 tions, and then giving a concise description (with 

 good figures) of the distinguishing features and 

 natural history of all the principal species, the most 

 important features, namely, the feeding and spawning 

 peculiarities of each, receiving particular attention. 

 Then follows the subject of pisciculture proper, which 

 forms the bulk of the volume. There are two kinds 

 of pisciculture— natural and artificial. The object of 

 natural pisciculture is to multiply the more valuable 

 species by favouring their conditions of existence. 

 Under this heading come such matters as the effects 

 of navigation, canal-making, and industrial works, 

 and the methods of combating these effects, and of 

 restoring natural conditions, the planting of canals 

 and dvkes with plants on which the useful species 

 mav deposit their eggs, or seek shelter, the erection 

 of ladders, and the construction of ponds. &c. By 

 "artificial pisciculture," on the other hand, is meant 

 the artificial fertilisation and hatching of the ova and 

 the subsequent rearing of the fr>-. With the principal 

 technical details of both kinds of pisciculture M. 

 Guenaux deals exhaustively in a methodical and dis- 

 criminating manner. As has been said, this is a 

 thoroughlv practical handbook, abounding in figures 

 from statistics, measurements, and the critical com- 

 ments of one who has had much first-hand experience 

 of every branch of the business. There are plenty of 

 good wood-cuts to illustrate construction of apparatus, 

 &c. A succinct but fairly comprehensive account of 

 aquatic invertebrate fauna and the flora next follows, 

 and there is, finally, an excellent section on the para- 

 sitic diseases of fresh-water fishes and of injurious 

 insects, reptiles, birds, and mammals. These chapters 

 are also amply illustrated. 



But even >I. Guenaux's knowledge and versatility 



G 



