Ivi 



Thirty-first Annual Report 



fishery investigations of the research steamer, the " Goldseeker," have 

 been under Dr. Fulton's charge, and have been carried out according 

 to a monthly scheme submitted to and approved by the Board. The 

 following is a summary of the work done last year : — 



Traivling Investigations. 



In the course of the year 183 hauls of the trawl-net were made, 73 

 of which were with the large otter- trawl, 80 with the beam-trawl, for 

 quantitative purposes, and 30 with the herring-trawl. The latter are 

 specially referred to below. The hauls with the beam-trawl were 

 made at the old trawling stations of the "Garland" (the vessel 

 formerly employed in the Board's scientific work), in the Firth of 

 Forth and the Moray Firth. As the investigations of the " Garland " 

 were begun in 1886, and carried on till 1896 in the Firth of Forth 

 and until 1 900 in the Moray Firth, comparison of the results as to the 

 relative abundance of the various species of the food-fishes in the two 

 periods will be of value. The trawling with the large otter-trawl was 

 made on various grounds, including the Great Fisher Bank, the 

 Witch Grounds, the grounds off' Aberdeen, and a special series of hauls 

 were made in J une and J uly at Fair Isle. 



The great majority of the fishes caught were individually measured, 

 the sizes being recorded, while large numbers were opened and the 

 condition of the reproductive organs ascertained and noted. Observa- 

 tions were also made in many cases on the contents of the stomachs, 

 in order to determine the food upon which the fishes subsist. These 

 records are being worked up for publication. 



Marking Experiments. 



The number of food-fishes which were "marked" and liberated in 

 1912 by the Goldseeker " amounted to 2360, viz., 2165 plaice, 133 

 witches, 60 cod, and 2 haddocks. Efforts were chiefly concentrated 

 on the plaice, which is the most immediately important species in 

 connection with the international fishery investigations, as well as 

 the fish which is best adapted for this particular method of research. 

 Of the plaice which were " marked " and set free 593, or 27 per cent., 

 were recaptured in the course of the year and up to the end of 

 February, 1913. This agrees very well with the proportion recap- 

 tured in the previous year, viz., 26 per cent. None of the marked 

 watches were recaptured, the fishes probably dying subsequently from 

 the handling, though special care was taken, and those marked 

 were obtained in comparatively shallow water at the mouth of the 

 Firth of Forth. Five of the sixty marked cod were caught later, or 

 8 per cent. 



The mark consists of a numbered vulcanite disc, attached to the 

 fish by means of a silver wire, or of a vulcanite stud, also numbered, 

 fixed in position by a rubber ring. The main objects of the marking 

 experiments are to ascertain (1) the migrations of the fish ; (2) their 

 growth ; (3) the intensity with which fishing operations are carried on. 

 For any of these purposes it is necessary that some time should elapse 

 in order that a sufficient amount of evidence may be accumulat.ed for 

 the formulation of satisfactory conclusions. There are some results, 



