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REPORT ON THE INVESTIGATIONS CARRIED ON 

 IN 1921 IN CONNECTION WITH THE LANCASHIRE 

 SEA-FISHERIES LABORATORY AT THE UNIVERSITY 

 OF LIVERPOOL, AND THE SEA-FISH HATCHERY 

 AT PIEL, NEAR BARROW. 



EDITED BY 



Professor JAMES JOHNSTONE, D.Sc, 



Honorary Director of the Scientific Work. 



Contents. 



Introduction. Jas. Johnstone ... ... ... ... ... ... 65 



Classes and other Work at Piel. A. Scott ... ... ... ... 96 



The Plaice Fisheries of the Irish Sea. Jas. Johnstone, W. Birtwistle 



and W. C. Smith. (See separate contents) ... ... ... 101 



A Biometric Study of Irish Sea Herrings. W. Birtwistle and H. Mabel 



Lewis 244 



Chemical Composition of the Mussel, Tables of Results. Pv. J. Daniel 269 



Some Diseases and Parasites of Fishes. Jas. Johnstone 286 



INTRODUCTION. 



The greater part of this Report consists of a summary 

 and discussion of the results of two investigations that have 

 now been carried on for a number of years : these are (1) the 

 plaice research, commenced by the Committee in 1908 and then 

 continued during 1919-21 as part of the work done under a 

 special grant made by the Ministry of Agriculture and Fisheries, 

 and (2) the biometric investigation of herring races, begun in 

 1913 as part of an international research. We think it desirable 

 that these routine observations should now be suspended so 

 that it may be considered what are the results and what they 

 indicate. For the opportunity of publishing the complete 

 results of the plaice work we are indebted to the Development 

 Commissioners, who have kindly allowed us to spend the balance 

 remaining ovei from the grant made for directed fishery 

 research in the Irish Sea. In addition to these two series of 

 data there remain Mr. Scott's numerous estimations of organisms 



