SEA-FISHERIES LABORATORY. 229 



average size was one and a half inches, and one hundred 

 of these mussels weighed seventeen ounces. Another 

 skear " Great Out Skear," covered with mussels one year 

 old, that is, three-eighths to five-eighths of an inch, was 

 found to be populated to the extent of 16,000 per foot 

 square. In some places a few two year old mussels were 

 mixed with the younger ones, and an area one foot 

 square contained 10,000 one year old mussels, 200-300 

 two year old mussels being also present. The mussel in 

 its natural state usually lives with the pointed end down- 

 wards, and consequently a large number can accommodate 

 themselves to very little space. Mussels of the same age 

 are never of a uniform size when they grow up, but when 

 they first settle upon the skear as spat they are all nearly 

 alike. Some slight favourable circumstance soon enables 

 a few to grow faster than the others. This advantage 

 becomes all the greater as the mussels increase in age. 

 At the end of the first year one may find a margin of a 

 quarter of an inch between the largest and smallest ones. 

 The competition between them becomes keener, and ere 

 long many of the smaller sizes are overwhelmed and 

 smothered, while the survivors continue to grow and still 

 further overcrowd the bed. The mussel, to enable itself 

 to keep at the surface, lengthens its byssus, and in time 

 the whole skear may be covered with mussels that are 

 only attached to their fellows, with practically no attach- 

 ment to the ground. The sea gradually undermines the 

 bed, and very soon these mussels can be torn away in 

 masses or rolled up like a carpet. When the mussel bed 

 reaches this condition the end comes with the first sform. 

 The seas sweep the mussels into masses, pounding them to 

 pieces or carrying them away into deeper water, where 

 they become buried under the shifting sands of the 

 channel bottom. This process of destruction goes on year 



