of the Fishery Board for Scotland, 



xxiii 



PART III. 



SCIENTIFIC INVESTIGATIONS. 



During the year 1919, the scientific investigations .in connection 

 with the sea fisheries were carried on under the supervision of Dr. T. 

 Wemyss Fulton, the Board's Scientific Superintendent, as far as pos- 

 sible on the same general lines as in previous years. With a stafi 

 still considerably reduced, the research work was conducted at the 

 Marine Laboratory at the Bay of Nigg, and in the laboratory at the 

 Old Post Office, Aberdeen, and the inquiries relating to the herring 

 and the herring fishery in Loch Fyne were carried on as circumstances 

 allowed, in continuation of the observations of preceding years. 



The research steamer Goldseeker," which was employed during 

 the war on Admiralty service, was reconditioned for scientific work, 

 and, after some difficulties in regard to the steam- winch were over- 

 come, left Aberdeen for the Moray Firth on the 11th July. Since that 

 time, it has been employed in carrying on the scientific investigations 

 at sea, as in the years^ before the war. 



The Hatching Operations. 



Although the stock of adult plaice in the spawning pond at the 

 Hatchery, Bay of Nigg, Aberdeen, has not been renewed or added to 

 since 1913, a fair number of fish remain, and they spawned as usual 

 in the early months of the year. It is estimated that about 2,000,000 

 fertilised eggs were collected from the spawning pond, between the 

 middle of February and the early part of April. Allowing for the 

 number which died in the hatching boxes at one stage or another, 

 about 1,700,000 plaice fry were produced, and liberated in the sea in 

 the neighbourhood of Aberdeen. 



Since the hatching of the plaice was begun at the Bay of Nigg, 

 the number of eggs which has been dealt with in the Hatchery is 

 approximately 448,000,000, and over 350,000,000 fry of the plaice 

 have been added to the sea to enrich the inshore grounds. The 

 hatching work entails an inconsiderable expenditure, since it is carried 

 on in conjunction with the. other work of the Marine Station, involving 

 some extra pumping and a small expenditure in putting out the fry. 



The Investigations on the Herring Fishery in Lochfyne. 



The investigations with respect to the failure of the Lochfyne 

 herring fishery for a number of years were carried on in 1919 as in 

 previous years, observations being made on the temperature of the 

 water at different depths and on the abundance of " plankton." the 

 minute floating life which forms the chief food of the herring. 



It was mentioned in the Report for 1918 that in the latter part of 

 that year, especially in October and December, considerable catches 

 of herrings were obtained in the lower part of Lochfyne ; and that in 

 December the shoals penetrated farther into the loch than they had 

 done for seventeen years. It was also stated that the fishermen 



