148 MARKETABLE BRITISH MARINE FISHES 



neighbourhood of the coasts ; none are found in mid-ocean, and 

 none in the ocean abysses. Many species on the other hand 

 approach towards fresh water at certain seasons, ascending 

 estuaries and never going far from them ; but no species is found 

 only in fresh water, although there are colonies of certain species, 

 such as shads, which have established themselves in lakes and re- 

 main there permanently and breed there. All these fishes occur 

 in very large numbers, and partly from their method of feeding, 

 partly from the persecution of numerous enemies to which they 

 are exposed, they are very timid and restless and swim with very 

 great rapidity. In consequence of these habits they are onl}' 

 caught with the drift net or the seine, or in bag nets and traps 

 in narrow waters ; the use of hooks for their capture is exceptional 

 and unimportant. 



There are six kinds in British water, all valuable as food, and 

 several of them of great importance commercially. The following 

 is a list of them with their chief distinctions : — 



I. Species in which the mouth is at the end of the snout and 

 the lower jaw somewhat longer than the upper. The sides of 

 the upper jaw come forward when the mouth is open, and close 

 the sides of the gape. 



1. The Herring. — Dorsal fin commences midway between 



the end of the snout and the base of the tail ; the pelvic 

 fins a little behind the commencement of the dorsal. 

 Scales of moderate size ; edge of the belly not very sharp 

 and the spines on it short and weak. No radiating lines 

 on the gill-covers. 



2. The Sprat. — Dorsal fin a little farther back than in the 



Herring; the pelvic fins very slightly in front of the 

 commencement of the dorsal. Scales of moderate size ; 

 edge of the belly very sharp, and the spines on it strong. 

 The body is rather deep and flattened from side to side. 

 No radiating lines on the gill-cover. 



3. The Pilchard. — Dorsal fin commencing nearer the snout 



than the base of the tail ; pelvic fins under the middle 

 of the dorsal. Scales large; the edge of the belly rounded, 

 and the spines on it weak, not sharp. Radiating lines 

 on the gill-cover spreading from above downwards. 



4. The Allis Shad. — Like the Pilchard in other respects,. 



