of the Fisher 1/ Board Jor Scotland. 73 



II. NORTH SEA INVESTIGATIONS. 



II. 



By Dr. T. Wemyss Fulton, F.R.S.E,, Scientific Superintendent. 

 (Plates I.-III.) 



INTRODUCTION. 



In the last Annual Report it was stated that the Fishery Board had 

 granted authority for the occasional employment of steam trawlers within 

 the Moray Firth and other parts of the territorial waters for the purpose 

 of scientific observations. These investigations were continued during 

 the greater part of last year, mostly in the Moray Firth and Aberdeen 

 Bay, but hauls were also taken in Lunan Bay, Sinclair Bay, Thurso Bay, 

 and in the deep water oft' Aberdeen. No expenditure was incurred in 

 the hire of the vessels, but since the inshore fishing in the bays is usually 

 more profitable than the deep-sea fishing, there was little difliculty in 

 obtaining the necessary facilities for the work, and in some cases facilities 

 were also granted for similar observations in the deep water off the 

 Orkney and Shetland Islands, where the fishing of the large steam 

 trawlers is now mostly carried on. 



Under the most favourable circumstances scientific work on board 

 steam trawlers must be pursued under certain difficulties and disadvan- 

 tages. The accommodation for the purpose is defective, and the obser- 

 vations had to be made entirely on deck ; but this disadvantage has now 

 been to some extent obviated by the use of a portable deck-house, which 

 can be fitted up on any of the vessels {see p. 332). The vessels are also 

 only partially under one's control, and since the chief consideration of 

 those connected with them is, naturally enough, the financial result of 

 the expedition, it was found in practice that more work could be accom- 

 plished when profitable catches were being obtained than when the fishing 

 was poor and unremunerative. On the other hand, there were certain 

 compensations in being able to ascertain the actual conditions under which 

 commercial trawling is carried on; to observe the proportions of immature 

 and unmarketable fishes to the marketable, their vitality when brought on 

 deck, &c., and, above all, to have at one's disposal the great numbers and 

 varieties of fishes which are taken by the large otter-trawls. 



The observations made on board the trawlers were as follows : — The 

 temperature of the surface and bottom water was determined at each 

 locality and the depth during each haul ; tow-nets and the dredge were 

 used when possible ; the number of each kind of fish caught in the net 

 was ascertained, and a note taken of the duration of the haul and of the 

 proportion of the fishes taken to market to those thrown overboard. 

 Large numbers of fishes were also measured and recorded in connection 

 with the investigation on the rate of growth of fishes (p. 326) and rare 

 specimens preserved. Since the trawling operations go on continuously 

 day and night, unless when interrupted by unfavourable weather, it was 

 not found possible to enumerate, examine, and record all the catches, even 

 with the assistance rendered. In some cases the mere separatio]i and 

 enumeration of the " offal," i.e., the unmarketable fishes, occupied hours. 

 In as many cases as possible complete records were made of the hauls ; 

 when that could not be accomplished the detailed record was limited to 

 the marketable fishes, the unmarketable being stated according to the 

 gross quantity, or estimated, as indicated in the Tables appended , In 



