AQUICULTURE 291 



mussels found a ready market at a good price. Shellfish 

 which in their original condition could never have been of 

 any use as food, had been turned into a valuable commodity 

 at comparatively httle labour and expense. The money 

 value to the fishermen of these mussels that had been trans- 

 planted for £50 was estimated to have been at least £500. 

 In 1904, again, a grant of £50 resulted in the transplanting 

 of some boat-loads of undersized mussels, which were sold 

 later on at a profit of over £500. 



In the following year (1905) a grant of £75 resulted in 

 the sale of the transplanted mussels some months later for 

 £579. On that occasion over 240 tons of the undersized 

 mussels had been transplanted in six days' work. It was 

 found that on the average the transplanting increased the 

 bulk of the mussels about 2 J times, and the increase in length 

 to the original shell was in some cases well over an inch 

 (see Plate XXVII). 



These experiments, on the industrial scale, were not 

 carried further. The Lancashire committee only desired 

 to show what could be done and how to do it, and had no 

 intention of running a commercial concern ; but the results 

 are very suggestive and encouraging as to what might be 

 done in the further cultivation of our barren shores. 



An interesting appHcation of scientific methods to the 

 improvement of a shellfish industry has been in practice 

 for some years at Conway, in North Wales. The extensive 

 mussel-beds in the estuary are badly polluted by sewage, 

 and have been under investigation by the scientific staff of 

 the Lancashire and Western Sea-Fisheries Committee since 

 1904. Dr. James Johnstone showed, as the result of many 

 experiments, that the polluted mussels, when relaid in clean 

 sea-water, were able to purify themselves by ehminating 

 from 90 to 95 per cent, of the sewage bacteria in two to three 

 days. He also found that the mussels can live in water 

 containing up to five parts per million of chlorine, while the 

 sewage bacteria are sterilized by one part of chlorine per 



