101 



CHAPTER 11. 



HABITS, FOOD, ETC. 



The habits of the adult sole in its natural state cannot be directly observed : we can 

 only ascertain the means by which it is captured, the character of the sea-bottom 

 whence it is taken, the animals which are taken with it, and the food which is found 

 in its stomach. By supplementing the knowledge thus gained with observations on 

 the living fish kept in large aquarium tanks we can obtain a tolerably complete 

 knowledge of tlie sole's mode of life. 



The sole is rarely, if ever, captured by any other instrument than the trawl. The 

 great majority of the soles brought to market are obtained by the large beam trawl, 

 worked by the large deep-sea trawlers, but it is also frequently captured by the 

 otter-trawl used chiefly by amateurs, and also by the small trawls used for catching 

 shrimps and prawns. The usual depth at which soles are found is from 20 to 

 40 fathoms, but it may exist at greater depths ; it probably does not extend beyond 

 100 fathoms. 



Adult soles may occur at any depth less than 20 fathoms, but usually in shallow 

 w^ater, less than ten fathoms deep, only young individuals are found. However, 

 exceptions to this rule occur not infrequently; the fislierman of the Plymouth 

 Laboratory has several times caught an adult sole in Plymouth Sound within the 

 Breakwater. Once he caught a full-grown specimen of large size in the Catwater, 

 which is the estuary of the River Plym, opening into the north-east corner of the 

 Sound. On May 9, 1889, he took a specimen 13| in. (35 cm.) long, a short dist.ance 

 from the mouth of the same estuary, and a third specimen he captured a little later 

 in another part of the Sound. Small specimens six and a half to nine and a half 

 inches (17 to 23 cm.) in length are not uncommon in the Sound, half a dozen being 

 frequently taken in two or three hours' work with the shrimp trawl. These immature 

 soles in fact, according to my experience, are more abundant within the Sound than on 

 the neighbouring open shores outside it. 



O/r Plymouth soles are comparatively scarce at the present time : it is rare to take 

 more than four or five in a single haul of the trawl, and sometimes only one or none 

 at all are obtained. At a considerable distance south of the Eddystone they become 



