oj the Fishery Board Jor Scotland. 



9 



to be unproductive in October and on various occasions since, both 

 in regard to the abundance of marketable fishes and to the profitable 

 nature of the fishing compared with the offshore grounds. 



On one of the occasions the trawler was equipped with a beam- 

 trawl as well as an otter-trawl, in order to allow comparison to be 

 made of the relative efficiency of the two nets on the same ground 

 at the same time, but in the second haul with the beam-trawl the 

 net was lost. The results of the first drag support the statement 

 previously made that the horizontal spread of the otter-net does not 

 greatly exceed the width of the beam-trawl, but fishes higher from 

 the bottom. It is thus relatively less efficient for the capture of 

 flat-fishes than of round-fishes. 



The Eelative Abundance, Distribution, and Migrations 

 OF THE Food Fishes. 



In the present Eeport the results of the investigations made on 

 board trawlers regarding the distribution and relative abundance 

 of the food fishes at different sizes, and the extent of their migra- 

 tions, are described by Dr. T. Wemyss Fulton. Among the fiat- 

 fishes certain species which begin their life in the shallow water, 

 or on the beaches, move out when older into deeper water, and 

 may be obtained in diminishing numbers at considerable distances 

 from land. Thus the plaice appears to pass its early stages exclusively 

 in the shallow water near shore, while the older forms, ranging 

 about twenty inches in length and not under fourteen inches, were 

 got in fair numbers in sixty-five fathoms, from eighteen to twenty 

 miles from Fair Isle, and in smaller numbers in water of the same 

 depth, sixty-five miles from Sumburgh Head, which was the 

 nearest land. None of these fish were under about three years of 

 age. The adult plaice were found in still greater abundance on 

 the Fisher Bank, in the middle of the North Sea, in thirty-four 

 fathoms. In all these localities the plaice present must have 

 migrated very considerable distances in the course of their growth, 

 in the latter instance probably from the Danish coast via the 

 Dogger Bank, and this agrees with the results of the marking 

 experiments. Observations on the rate of movement of the 

 plaice in the large tidal pond at the Bay of Nigg show that when 

 leisurely swimming they may travel considerably over a mile in 

 one hour. 



The turbot was also occasionally found far from shore in deep 

 water, and it also begins life in shallow water; while the brill is more 

 restricted in its range. The dab, on the other hand, not so strictly 

 confined in its early stages to the shallow water, was found further 

 ofishore in deeper water than the plaice, but, like the latter, in 

 greatly diminished numbers. 



The observations in regard to the round-fishes also indicate an 

 extensive wandering or migration. It was found that as a rule the 

 adult cod were more numerous relatively and absolutely on the 

 inshore grounds, that the larger codling were more abundant off- 

 shore, and that the smaller codling under two years of age were 



