286 THE BIOLOGY OF THE SEA-SHORE 



going either to distant markets, or being utilised locally. 

 Again, should the demand from the big inland markets 

 cause prices to rise above normal, a number of gatherers are 

 temporarily attracted and there is increased local production. 

 These factors can be seen in operation over and over again, 

 in almost any locality offering a large supply of shore products. 

 During the war there was a great reduction in the value 

 gathered, owing to more remunerative employment being 

 available for the few who remained. The few who did 

 continue the work, however, obtained greatly increased 

 prices. The following data (see Annual Report of Sea 

 Fisheries for 1914, Pt. I., Appendix A) refer to 1914. 



At Boston (Lines.) 59 boats were licensed for mussels, 

 and 30,000 cwts, valued at ^(^2250 taken from the beds in 

 the Wash, etc. In addition 9600 cwts. were transplanted 

 to more favourable places. Of cockles 94,000 cwts. were 

 obtained. The value of the oysters marketed from the Colne 

 averaged for the three seasons previous to the war between 

 5(^13,000 and ^^14,000. From Tollesbury and Mersea, 

 3,160,975 oysters value ^12,035 were marketed in 1913-14, 

 the stock on the ground being estimated on August 31st, 

 1 914, at 3,618,780 : also 18,000,000 of " half ware." 



Mussels may sometimes be found to occur on the sea- 

 shore in such dense crowded masses as almost to obscure the 

 rocks. Such beds are frequently termed " scars " or " skears " 

 (a Lancashire term which is useful to denote beds of this 

 type), and the shell-fish inhabiting them may grow fairly 

 well, but without attaining marketable condition, or may 

 remain stunted, thick-shelled, and coated with the Cirripede 

 Balanus. The shells of these mussels, through being 

 constantly wetted and dried, become rough and unsightly ; 

 the chitinous outer shell-layer (the periostracum) being lost 

 and the prismatic layer thus rendered visible gives the shells 

 a blue colour (Wright, 19 17), whereas the rapidly grown 

 shells are either smooth black, or variegated (" pitch pine " 

 mussels). The causes of lack of growth are over-crowding, 

 and insufficiency and irregularity of food supply (Diatoms, 

 Protozoa, detritus, etc.). If such mussels are removed to 



