202 THE SEA FISHERIES 



The mussels are hauled into the boat, where, after a sufficient number 

 has accumulated, the small ones are riddled out, and returned to 

 the beds. The imposition of a size limit is necessary if the cockle 

 and mussel beds are to be protected from the results of overfishing 

 In the case of sedentary organisms like these it is possible completely 

 to destroy a bed by unrestricted fishing, and there can be little 

 doubt that the by-laws enforcing a size limit have been efficacious 

 in preventmg the wholesale extinction of public fisheries for shellfish. 

 Apart from man the chief enemy of the mussel is the starfish and 

 certam species of flat-fish, particularly the plaice, dab and flounder. 

 The former pest attacks the mussel at any stage of its existence 

 after it has settled down from its free swimming larval life, and 

 the destruction caused in a comparatively short time by a horde of 

 starfish must be seen to be realised. The flat-fish only attack the 

 mussel when immature and the shells are delicate. 



The chief enemy of the cockle is the " sea-gull." Of the numerous 

 species of bird which come under this designation the herring gull 

 {Lams argentatus) and the lesser black-backed gull {Lams fuscus) 

 are the chief offenders. The use of the instrument known as the 

 " Jumbo " involves the bringing to the surface of a number of small 

 cockles, which, before they can sink again, are devoured by the 

 gulls. These gulls follow the cocklers at their work. Three herring 

 gulls shot on the Flookburgh sands (Lancashire) early in 1905, had 

 respectively 13, 13 and 24 whole cockles in their gullets, in addition 

 to recognisable fragments of shells in the gizzard and iatestine 

 (see Fig. p. 202). Inquiries have been made from time to time as to 

 the destruction to sea and shellfish caused by marine birds, but such 

 investigations have hardly been sufficiently detailed and thorough 

 to justify much reliance being placed on their conclusions.^ 



Both cockles and mussels when gathered contain a certain 

 amount of estuarine water, and if sewage be present in such water, 

 the risk of consuming the shellfish must be very grave, more espe- 

 cially if the shellfish be consumed in an uncooked condition. The 

 authorities which regulate the gathering of shellfish from public 

 fisheries are, in Scotland the Fishery Board, in Ireland the In- 

 spectors of Irish Fisheries, and in England and Wales the Local 

 Fisheries Committees. The regulations are framed from a purely 

 fishery standpoint, and deal principally with a close time and a 

 size limit below which it is illegal to remove shellfish from the beds. 

 Although the Local Fisheries Committees have no power to specify 

 a minimum size for the landing or sale of sea fish {sensu striclo) 



1 See Cumberland County Council. Report on the Food of the Black-headed GuU 

 (Lams ndibundus Linn), by D. L. Thorpe and L E. Hope Carlisk ^^o; and 

 Suffolk and Essex Fishery Board. Report of Sub-Committee appomted to make 

 a^angements for and to investigate the feeding habits of gulls durmg the year 1913. 



