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Part III. — Twenty -third Annual Report 



food and other fishes on the grounds visited in different years and 

 at different seasons, but observations are also made on the repro- 

 duction of the fishes, their spawning, food, and on various other 

 questions connected with their life-history and habits, and at the 

 same time collections of the plankton, or floating organisms, are 

 obtained, and experiments made with large-meshed and small- 

 meshed nets. 



Although the employment of commercial vessels in these 

 investigations is associated with certain inseparable disadvantages, 

 it is possible with the large ship, the efficient trawl, and the 

 experienced trawlers on board, to make a much more thorough 

 examination of the bays than wa3 formerly the case. From the 

 fact, moreover, that the trawling operations are carried on under 

 the same conditions as in commercial fishing, opportunities are 

 afforded for certain observations of importance, as the proportion 

 of the marketable and unmarketable fishes which are caught, the 

 relation between the sizes of the fishes captured and the dimensions 

 of the meshes of the net, and the amount of destruction of 

 immature fish that occurs on different grounds and at different 

 seasons. 



For some years past, as mentioned in previous reports, by an 

 arrangement with the Technical Education Committee of the 

 County Council of Aberdeenshire, representative fishermen from 

 various parts of the coast of that county have visited the Labora- 

 tory and Hatchery in spring to receive demonstrations on various 

 aspects of the life-history and habits of fishes, such as may be of 

 interest and use to them in the course of their calling. The 

 fishermen have been much interested in the instruction they 

 received, and as it appeared to the Board advantageous to 

 encourage the desire for such knowledge on their part they issued 

 a circular to the other sea-board County Councils inviting them 

 also to send fishermen if they thought proper so to do, to attend a 

 similar series of demonstrations. This invitation was accepted by 

 the County Council of Argyleshire, a number of fishermen from 

 that shire subsequently visiting the Laboratory and Hatchery, and 

 it is under consideration by some of the others. 



Trawling Investigations. 



In the course of the year the results of 91 hauls of the large 

 otter-trawl in the closed waters were recorded, of which 75 were 

 taken in the Moray Firth, 14 in Aberdeen Bay, and two in Sand- 

 side Bay, on the north coast. The examination of the grounds was 

 made in January, March, April, September, October, November, 

 and December, the localities in the Moray Firth which were most 

 thoroughly investigated being Burghead Bay and adjacent parts of 

 the south coast, the Dornoch Firth, and the grounds off the coast 

 of Caithness. Some hauls were also taken at Smith Bank and in 

 the deeper portions of the Firth at the so-called "witch-grounds." 



The aggregate number of fishes of all kinds caught in the 

 recorded hauls was 63,525, and of these 44,538, or 70 per cent., 

 were marketable, the other 18,987, or 30 per cent., being thrown 



