294 MARKETABLE BRITISH MARINE FISHES 



surface of the sea, but have not been traced. The young from 

 i inch in length upwards are well known : in their first summer 

 they swarm around rocky weed-covered shores, and are seen in 

 numbers about the piers of harbours. At the same time larger 

 specimens about a year old are seen and easily caught with hooks 

 in harbours and up to a certain distance from the shore. The 

 limits of size of the year-old fish have not been definitely ascer- 

 tained, but many of them are only from 4 to 7 inches long. The 

 size at which spawning commences is also uncertain. 



Thus there is no doubt that the young of this fish live near 

 the shore, while the adults roam far out to sea and to consider- 

 able depths. In the Irish Survey 164 specimens under 4 inches 

 in length were taken, all at depths less than 5 fathoms, while 

 43 adults over 30 inches in length were taken at 70 fathoms. 

 As in the case of other species, the young live principally 

 on the small Crustacea which abound among the sea-weeds or on 

 the bottom, while the older fish feed principally on other fishes, 

 in the North Sea especially on the herring. In the young fish 

 the upper jaw is longer, and the barbel is well developed, but 

 beyond a length of about 12 inches the lower jaw becomes the 

 longer and the barbel a mere rudiment, a change which corre- 

 sponds to the change of habits and food. 



The Pollack (Gadus pollackius). 



Distinguishing Characters. Lower jaw longer than in the 

 coal-fish, no barbel, body deeper, and the colour green instead of 

 blue or nearly black. It grows to 3 feet in length or more, but 

 is usually seen between 18 inches and 30 inches. 



Habitat. From Norway to the Mediterranean ; in the British 

 Isles commonest on the south coast, especially off the shores of 

 Devon and Cornwall. It has not been taken at depths greater 

 than 40 fathoms. 



Food. In the Irish Survey the larger pollacks were found to 

 have only other fishes in their stomachs, namely sand eels, sprats, 

 scald-fish, gurnard, and others. The younger specimens con- 

 tained crustaceans, worms, and molluscs. 



Breeding. On the west of Ireland pollack were found to be 

 ripe in April and May. In Shetland ripe fish were obtained in 



