SEA-FISHERIES LABORATOEY. 



175 



grounds and at different times. The same kind of results can, 

 however, be obtained by making direct experiments. Plaice 

 were marked in the Irish Sea in small numbers, the region 

 itself being a small one, and there were two principal series of 

 experiments, in the area just off the estuary of the Ribble and 

 in Red Wharf and Beaumaris Bays. The numbers of fish 

 marked are as follows : — 



(1) Offshore from the Ribble Estuary (" Liverpool Bay ") : 

 13th July, 1905 31 plaice. 



12th June, 1906 



40 „ 



9th July, 1906 



3rd July, 1907 



5th June, 1912 



50 „ 

 147 „ 



212 „ 



3rd October, 1912 



153 „ 



3rd June, 1913 



134 „ 



17th July, 1913 



17th September, 1913 



65 „ 



297 „ 



Total 



1,129 plaice. 



(2) In Red Wharf and Beaumaris B 



ays: 



12th Nov., 1904 



42 plaice 



12th Nov., 1904 



■ 49 „ 



1st Feb., 1906 



44 „ 



21st Feb., 1906 



8 „ 



19th Sept., 1906 



6th Feb., 1907 



41 „ 

 92 „ 



24th Oct., 1907 



120 „ 



20th Nov., 1913 



220 „ 



Total 



616 plaice. 



The methods employed were those adopted by the English 

 investigators. The mark was a bone button on the white side 

 of the fish and an oval, concave, hard brass disc on the coloured 

 side. These two marks were connected by a silver wire passed 

 through the body about -|- inch below the edge of the fin on the 

 dorsal margin. Fixing the mark was very easy, and we were 

 unable to trace any serious injury to the patient. Later on 



