THE SHELLFISH INDUSTRY 307 



to the quiet, sedentary existence they are henceforward 

 to lead. At this stage they are spread far and wide by 

 tides and currents, settling wherever they find a suitable 

 bottom ; and in some places there are special areas of 

 soft oozy mud, quite distinct from the surrounding sand, 

 which provide ideal nurseries for young or " seed " cockles, 

 which form a compact layer just beneath the surface. 

 As they grow, the boundary of the nursery extends on all 

 sides over the surface of the sand but in the centre, where 

 there is no possibility of further extension, the surplus 

 population is forced to the surface whence it is largely 

 carried away by currents, part to assist in the restocking 

 of the sandy beds, and part to destruction. Cockles have 

 the common enemies of all such shellfish ; they are eaten 

 by starfish, bored into by dog-whelks, and, especially in 

 their younger stages, eaten by gulls, and probably also by 

 flat-fish which swim over the beds when the tide is up. 

 Owing to the exposure of the sandy beds, frost in winter 

 or great heat in summer are both fatal to the cockle. Storms 

 and currents also do great damage, the former by throwing 

 the cockles above high-water mark and the latter by wash- 

 ing them from favourable to unfavourable localities. 



The most important cockle industries in Great Britain 

 are in the Wash, the Thames estuary, Carmarthen Bay, 

 and Morecambe Bay. The cockles may be scraped up 

 by hand, or may be dug, but more often short-handled rakes 

 with large teeth or scrapers consisting of sickle-shaped 

 pieces of iron are used. It is customary in the Morecambe 

 Bay fishery to tread the sand with bare feet so as to bring 

 the cockles to the surface, while a wooden frame with a 

 base board which rests on the sand, known as the '' jumbo," 

 is used to force the animals to the surface in some parts 

 of Lancashire. After they have been gathered and collected 

 in heaps the cockles are washed and then riddled through 



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