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REPORT ON THE INVESTIGATIONS CARRIED ON 

 IN 1920 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. 



(With Text-Fignres.) 



Contents. 



Introduction (J. J.) 



The Work of the Piel Laboratory (A. S.) 



Plaice Measurements made in 1920 (W. B.) 



Herring Investigations in 1920 (W. B.) 



Temperature Variations and Tides (R. J. D.) ... 



Seasonal Variations in the Composition of the Mussel (R. J. D.) 



Intensive Study of Port Erin Plankton (W. A. H., A. S.,and H. M. L 



Variability in Port Erin Plankton (W. A. H.) 



Sole Measurements in 1920 (J. J.) 



Black littoral sands (J. J.) 



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95 

 102 

 116 

 127 

 146 

 157 

 161 

 175 

 178 



INTRODUCTION. 



This Report, like those that have been issued since 1914, 

 must again be a small one. The reason for this is mainly 

 the greatly- increased cost of publication, but there are also 

 other difficulties peculiar to the circumstances of the time. 

 There is no doubt that the fishery industries are in a very 

 serious condition — perhaps even one of crisis — and so one is 

 obliged to try to discover in what ways the scientific research 

 now being carried on can be of immediate assistance. Obviously 

 the investigations that are instigated by a statutory fishery 

 authority in this country must have, for their ulterior objects, 

 the attainment of results, or solutions, or information of some 

 kind that will be of material advantage to the industry — that 

 is their justification as economic research. Now one may 



E 



