SEA-FISHERIES LABORATORY. 



123 



the typical varied Laminarian zone invertebrate and fish 

 faunas, in Rock Channel, in the Dee, and off Air Point. 

 The in-shore parts of Liverpool Bay are probably the 

 scene of hydrographic changes to an extent greater than 

 any other corresponding area in the Irish Sea, and it is 

 probable that to these changes may be attributed snch 

 remarkable instances of fish migrations on the large scale 

 as the exceptional abundance of herrings in the early 

 nineties, and the extensive immigration of haddocks in 

 the same decade. 



Cents ^ ' ' £ 



Fig. 14. Percentages of plaice at and over each unit of length, in the 

 catches made inthe Mersey area by trawl nets of various sizes of mesh. 



(1) The Shrimp-trawl 



were made by a 25 feet trawl net of J inch mesh. 



C a t c h e s.— These 

 The 



numbers are fairly large, and the tables may be 

 regarded as affording a very reliable picture of the size 

 of ihe small plaice inhabiting the nursery grounds. It 

 will be seen that there is little or no significant difference, 



