Scottish herring girls, migrant laborers, 

 work their way south from port to port 

 along with the trawlers which follow the 

 seasonal movements of the herring shoals. 

 Their job is to clean and pack the catches 

 for marketing. They work their way from 

 Scotland down the east coast of England. 



Mackerel are among the fastest and most 

 graceful swimmers In the sea. They grow to 

 about eighteen inches, inhabit the northern 

 latitudes, and travel In vast shoals. From 

 about February to October they live in the 

 surface waters and for the remainder of the 

 year live near the bottom. 



Mackerel have a different migration pattern. At the end of 

 October they leave the surface waters, swim toward the bottom, 

 and concentrate in troughs on the sea bed. Toward the end of 

 December they start to spread out over the sea bed, feeding on 

 such small animals as shrimps, worms, and little fishes found near 

 the bottom. Early in the following year they return to the surface 

 waters and start their spawning migrations, which take them in 

 large shoals to the south of Ireland. In the early summer the female 

 lays up to half a million eggs, which also appear to be of "migratory" 

 habits. For about two days they float at the surface, then they 

 gradually sink halfway to the bottom and remain suspended there 

 for a few more days. Eventually they settle to the bottom and the 

 young mackerel hatch. 



Not all fishes migrate. The herring, for example, breeds in cold 

 coastal waters of relatively low salinity, where the temperature is 

 less than 14° c. and the salinity less than 3.5 per cent. Fishermen 

 used to think that there were annual mass migrations of herring 

 from north to south in search of these favorable conditions. What 

 actually happens is that the warm and highly salty water of the 



