148 Mussel Beth; their Produeflckfj and Mdlntenaiice 



suggested. 8ome of these are fairly populous, and they exist wherever 

 the influence of freshwater is felt, and there is suitable ground. These 

 beds should be surveyed, and their population estimated, in order to be 

 prepared for the possible failure of the usual sources of seed mussels. 

 These small colonies are stocked automatically by the spat liberated by 

 mussels in their vicinity, but more favourably situated. They represent 

 a very small proportion of that which is washed out to sea and destroyed 

 in various ways. They form a never failing, if not very considerable, 

 source for the replenishment of the fishing grounds, which, by means of 

 low stakes, or by diverting the stream to flow over a greater area of 

 beach, could doubtless be considerably developed with a small outlay. 

 This matter deserves serious attention. That the seed beds (generally 

 more seaward in situation) may fail is no remote contingency, and such 

 has been the case at Barmouth during 1916 and 1917. The winter 

 storms and spring floods have resulted in serious damage being done to 

 the beds, and several years may elapse before they regain their former 

 dense population. 



The Barmouth Mussel Fishery. 



With regard to Barmouth and its mussel fishery, only a few words 

 can be said in this place. The beds are of small extent, and always 

 covered by a considerable depth of water. Since they are also situated 

 on steeply shelving banks, their area is difficult to estimate exactly. 

 If well stocked, they might give a maximum yield of mussels to the 

 value of £300 or £400. These figures, however, are not based upon 

 actual calculations, but, when all the factors are taken into consideration, 

 they are probably not very wide of the potential production. 



Purification of Mussels. 



Most (and probably all) of the rivers and estuaries of Great Britain 

 suffer from sewage and industrial pollution, in varying degrees. Sewers 

 and drains empty into them, and also the effluents from factories and 

 works on their banks. The sewage is often permitted to escape in an 

 untreated condition, and this is the state of affairs that prevails in the 

 Cardigan Bay estuaries, which, on the other hand, suffer very little from 

 industrial waste products. This condition of things is obviously very 

 unsatisfactory when considered in relation with the mussel beds, and 

 extensive bacteriological analyses of water taken in relation with the 

 fishing grounds reveal the presence of bacteria resembling those found 



