154 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY 



that plaice spawn just offshore from Peel, in Isle of Man, and 

 in the entrance to the Solway Firth. In 1920 we were able to 

 investigate the latter ground. During the months January 

 to April the Lancashire and Western Sea-Fisheries Committee 

 allowed us the partial use of the s.s. " James Fletcher," and 

 about thirty hauls were made on the region between Bamsey 

 Bay , in Isle of Man, and the entrance to the Solway Firth ; 

 100 drift-bottles were set free, and 367 plaice were marked 

 and liberated. The results of these investigations enable us 

 to describe the northerly spawning ground under the conditions 

 of 1921. 



It lies about eight miles to the -west of St. Bees' Head, in 

 Cumberland, extending North and South for about eight to 

 nine miles. Its bearings are : 



Centre, 7 miles W. by S. from St. Bees' Head. 



Northern end, 9' N.W. from St. Bees' Head. 



Southern end, 9' W. by S. from St. Bees' Head. 

 Its depth varies from 15 to 20 fathoms. It is situated in nearly 

 the coldest part of the Irish Sea (during February and March). 

 There are several banks off the N.E. of Isle of Man (" Bahama," 

 " King William," and the " Shoals "). Between these banks 

 and the fishing ground in the entrance to the Solway, called 

 the " Slaughter," there is an interchange of plaice, such that 

 the bigger fish tend to migrate from the " Shoals," about 

 February, over to the " Slaughter," where they spawn. The 

 spent fish then disperse, many of them returning to the Shoals' 

 area and to the South-west. 



In February of 1921 mature plaice were found between the 

 " Shoals " and the spawning ground. In March they were 

 found in greatest abundance on the spawning ground, and at 

 the middle of April no mature fish at all were found there, but 

 spent plaice were then to be taken on the " Shoals." About 

 March 21st the spawning season culminated, and by April it 

 was practically over. 



