SCIENTIFIC REPORTS. 



I.— TRAWLING INVESTIGATIONS. By Dr. T. Wemyss Fulton, 

 F.R.S.E., Superintendent of Scientific Investigations. 



Introductory. 



The investigations into the condition of the fishing grounds, particularly 

 in the closed waters of the Moray Firth and Aberdeen Bay, which were 

 commenced four years ago by means of steam-trawlers, were continued last 

 year, and a voyage was also made to the offshore waters lying off the 

 mouth of the Firth of Forth. In the Moray Firth the more important 

 areas were examined in February, March, April, June, October, November, 

 and December, and the grounds in Aberdeen Bay were visited in the same 

 months. On each occasion the places where fish were found to be most 

 abundant were chiefly worked over ; the total number of hauls made in the 

 Moray Firth, the results of which were recorded, was 101, and the 

 number in Aberdeen Bay was 29, making a total in the closed waters of 

 these areas o£ 130 drags, in addition to 18 in the offshore waters, or 148 

 altogether. The localities in the Moray Firth which were most thoroughly 

 examined were Burghead Bay and the Dornoch Firth, as well as Smith 

 Bank, the grounds off" Lossiemouth, off the Suters of Cromarty, and the 

 coast of Caithness. 



The total quantity of fish taken in the course of the investigation was 

 large, amounting to 180,51.5 in the completely recorded hauls, and of these 

 126,485 were of a kind or size to be marketable, and 54,030 were un- 

 marketable and were thrown overboard. 



One of the chief objects of these investigations is to ascertain the 

 changes in the abundance of the food and other fish in the closed waters 

 in different years and seasons, but observations are also made on the con- 

 dition of the reproductive organs of the fish, their spawning, food, and on 

 various other points connected with their life-history; while at the same 

 time the temperature of the surface and bottom water at the various places 

 is observed and recorded ; and from the fact that the actual trawling work 

 is carried on precisely as it is for commercial purposes, opportunities 

 are thus afforded for certain observations, as, for example, the proportion 

 of the various kinds of fish captured in the net which are marketable and 

 the proportion unmarketable, the influence of the size of the mesh of the 

 net on the size of the fish caught, &c., which would be otherwise difficult 

 to obtain. Collections of the floating organisms or plankton were also 

 secured, and a number of experiments made with small-meshed nets with 

 the object of procuring collections in connection with the study of the 

 rate of growth of fishes and their distribution. 



With the large commercial trawl, the efficient ship, and the experienced 

 trawlers in charge it is possible to make a much more extensive and 

 thorough examination of the grounds than could formerly be done. 



The results of the investigation are given in detail in the following 

 pages and in the Tables which are appended. 



The Proportion of Marketable to Unmarketable Fishes. 



As already mentioned, the proportion of the unmarketable to the market- 

 able was 54,030 to 126,485, which is therefore a very considerable 



