118 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



curves I think that these plaice had inhabited this area 

 during the entire summer and autumn, and had been 

 practically unfished. The hauls for March and November 

 are graphed as fig. 12 B. 



Barrow Channel. 



The sample catches made in this district were mostly 

 small ones, being made by one of the Bailiff's sailing 

 boats, employing a 25-feet trawl. They are, however, 

 sufficient to indicate the changes taking place. Barrow 

 Channel is not a " nursery," that is, it is not a shrimping 

 area characterised by a small-plaice population, and the 

 flukes that are found there in abundance during the 

 summer and autumn are an immigrant population. The 

 family of curves in fig. 16 represent the changes 

 during the first four months of the year, and have been 

 drawn, as already described, by changing the origin of 

 co-ordinates in each case, so that it is situated on the 

 point representing the modal size and frequency. Now, it 

 will be seen at once from the graphs that the plaice 

 population is, as it were, being eaten aw T ay from one end ; 

 it is the larger fish that are disappearing during those 

 months, being caught by the stake nets in this neighbour- 

 hood, or perhaps migrating outwards towards the 

 spawning area off the Cumberland coast. May is the 

 transitional month, and an m-shore migration, or perhaps 

 a migration from other small-fish areas, begins, so that 

 from that month till about October plaice are abundant, 

 and are fairly large fish. But the stock is not being 

 replenished after the middle of the year, and we find from 

 then that the fish become less abundant and the larger 

 sizes are fewer and fewer as the year progresses. 



The modal size shows significant variations from 

 season to season. It is at a minimum — about 17*5 cms. — in 



