SEA-FISHERIES LABORATORY. 199 



NOTES ON THE FOOD OF YOUNG FISHES. 

 By Andrew Scott. 



The tow-nettings taken during the summer months 

 frequently contain the post-larval, and later stages of 

 various kinds of fishes. In some cases identification is 

 tolerably easy. In others, the work of assigning the 

 post larval fishes to any particular species, is sometimes 

 an impossibility. These tender objects are very easily 

 mutilated in capture. In all cases, even when the young 

 fishes cannot be identified with certainty, the stomach and 

 intestines are now being examined to find out what the 

 fish has been feeding on. The internal organs owing to 

 the size of the fish, are naturally small, and cannot be 

 examined in the ordinary way. The methods adopted in 

 this work which give fairly satisfactory results are, (1) 

 removing the entire alimentary system with the aid of a 

 low power dissecting microscope, then carefully dissecting 

 the stomach under a Zeiss A, or Leitz No. 3 objective, a 

 cover glass is next put on, and the whole contents care- 

 fully gone over ; (2) dehydrating, clearing, and mounting 

 the stomach, or even the whole fish, in the ordinary way 

 for a permanent preparation in Canada balsam. The 

 former method has the advantage that little time is taken 

 up in the work. The latter one may take a few hours, 

 and the results do not always repay the labour involved. 

 As a rule, the shorter method is now employed. All the 

 young fishes examined were caught by an ordinary open 

 tow-net, worked just under the surface of the sea. The 

 following are the fishes that have been examined, with 

 the locality of capture, size in millimetres, and food 

 found. 



