SEA-FISHERIES LABORATORY. 



193 



Length-Frequencies of Age-Group II $ ? in the Mersey 

 Estuary, 1909-1913. 





May. 



June. 



July. 



August. 



September. 



14-5 



— 



3 















15-5 



4 



20 



5 



— 



— 



16-5 



2 



28 



13 



— 



— 



17-5 



8 



35 



16 



4 



— 



18-5 



6 



49 



23 



5 



1 



19-5 



32 



46 



44 



12 



— 



20-5 



43 



23 



39 



11 



1 



21-5 



24 



17 



33 



13 



3 



22-5 



13 



4 



38 



14 



3 



23-5 



10 



3 



14 



14 



3 



24-5 



3 



— 



14 



7 



3 



25-5 



2 



— 



6 



1 



2 



26-5 



— 



— 



— 



— 



1 



27-5 



— 



— 



2 



— 



2 



28-5 



— 



— 



2 



— 



— 



Mean ... 



20-46 



18-54 



19-29 



21-51 



23-56 



Error of 













Mean 



±0-105 



±0-08 



±0105 



±0-148 



±0-355 



From this we find that the growth rate is apparently 

 very irregular, dropping from May to June, and then 

 rising. This means, of course, that the normal growth 

 rate of an already existing population in May is partially 

 swamped by a great influx of fish in June, and that these 

 fish are smaller than those already present since they have 

 been living under less favourable conditions. 



(d) The Plaice Fishery in Beaumaris and Red Wharf Bays. 



This is a fishery of rather a different kind from that 

 near Nelson Buoy and off the Estuary of the Mersey. The 

 latter are grounds which depend for their stock of fish on 

 the stock present in the nurseries inshore from them, that 

 is, in the Dee, Mersey, Kibble, and in Morecambe Bay. 

 This is also the case, but to a much less extent, with the 

 plaice fishery offshore from Great Orme's Head and 

 Point Lynus, for while there are, doubtless, nursery 



