252 SCIENCE PROGRESS. 



taking active steps to foster scientific inquiry in this direc- 

 tion, and contemplates, sooner or later, to carry out 

 experiments in the hatching of marine food-fishes. Thus, 

 for example, a year or two ago the German Government 

 established at Heligoland an admirably equipped biological 

 station for the scientific investigation of the North Sea 

 fisheries. 



It has yet, of course, to be proved that the artificial 

 hatching of marine fishes, even on a large scale, will be 

 beneficial to the fisheries generally ; yet the importance 

 of the issue demands an exhaustive trial. Almost 

 everywhere during the last decade or two, complaints 

 have been made as to the decrease of important marine 

 food-fishes. Especially have the large halibut, turbot, 

 brill, soles and other flat-fishes become rare. In Britain, 

 this alleged diminution has been connected — for the 

 last decade at least — with the extension of beam -trawl- 

 ing in our waters. Consequently, the legislature has closed 

 the inshore area all round Scottish shores, and even con- 

 siderably beyond that limit in certain places, as in the 

 Moray Frith and the Frith of Clyde. Many thousand 

 square miles of water are thus placed solely at the disposal 

 of the liner. 



The hatching of sea fishes on a large scale offers con- 

 siderably greater difficulties than that of freshwater forms. 

 The experimenter in his arrangements has occasionally to 

 deal with the whole force of the waves in securing pure 

 water for his tanks and ponds. Pumping is generally re- 

 quired, and the pipes and other apparatus must be specially 

 constructed. Again, the necessary food for the minute and 

 delicate young must be present in the tanks or other 

 enclosures if he wishes to rear them beyond the larval 

 condition ; while predatory forms and decaying sea-weeds 

 must be absent. Instead of young- fishes, as in the salmon, 

 which are capable of being handled with safety, the marine 

 food-fish, with few exceptions, on its escape from the egg 

 is a tiny, transparent creature, scarcely visible in the sea- 

 water, and devoid of a mouth. 



While here and there in our own and other countries 



