of the Fishery Board for Scotland. 



11 



During the current season (1897) the artificial propagation of 

 plaice is being proceeded with on a large scale, but owing to the 

 earlier publication of the Annual Eeport this year, it is not possible 

 to give here a statement of the results of the work, which is still in 

 progress. As stated in last year's Eeport the fry produced in the 

 hatchery are being transferred to certain sea-lochs, which are to 

 a large extent cut off from free communication with the open 

 sea, and observations are being made to test the results on the 

 relative abundance of the same species within the areas selected. 



The hatching work has hitherto been much impeded by the want 

 of suitable ponds or enclosures of sea-water in which the adult 

 spawners could be retained from one season to another, and by 

 means of which it would be possible to retain the fry until towards 

 the close of the post-larval stage, when they begin to assume the 

 form and habits of the adult, and are in a much better condition to 

 successfully meet the influences tending towards their destruction. 

 In the present Eeport will be found a paper by Mr Harald Danne- p. 175. 

 vig, giving the results of experiments he has made with the view of 

 ascertaining the methods by which this may be accomplished. Some 

 of the fry of the plaice which were hatched in the establishment 

 were kept in suitable vessels of unfiltered water, to which tow-net 

 collections — that is to say, the gatherings of minute organisms 

 found naturally in sea- water — were added. By this means the fry 

 were reared through their post-larval stages, until they had under- 

 gone their transformation into little plaice and settled on the bottom. 

 Their food consisted to a small extent of diatoms, and chiefly of 

 minute crustsecea and larval mollusks. 



These experiments point to a method by which the utility of 

 artificial propagation might be considerably extended, namely, by 

 retaining the fry for a few weeks in suitable enclosures of sea-water 

 before they are transferred to the sea. 



The Currents in the North Sea and their Eelation 

 to Fisheries. 



In recent years, the attention of a number of investigators has 

 been directed to the hydrography of the North Sea, and several 

 enquiries and series of observations have been made with the object 

 of determining its principal physical conditions with especial relation 

 to the movement of its waters. During the last two years and a 

 half some thousands of drift-bottles have been thrown into various 

 parts of the North Sea, principally from the ' Garland,' of which 

 about five hundred have been recovered, and from careful com- 

 parison of the course taken, combined with a study of the 

 prevailing winds throughout the period, it has been possible 

 to ascertain the general circulation of the surface water. The 

 results are given in a paper in the present Eeport by Dr p. 334. 

 T. Wemyss Fulton, the Scientific Superintendent, in which it is 

 shown (1) that surface water passes into the North Sea from the 

 Atlantic round the north of Scotland and in the neighbourhood of 

 the Orkney and Shetland Isles, and then moves southwards along 



