of the. Fishery Board for Scotland. 



93 



of salmon marketed at Billingsgate, which used to form a regular item in 

 these reports, have been gradually discarded on account of a growing 

 custom to market salmon in centres other than Billingsgate, London being 

 no longer, therefore, a true gauge of the Scottish catch. In this connection, 

 however, I may mention that a most interesting examination of Billingsgate 

 returns for Scotland, England, and Ireland (1905-1916) has been given by 

 Mr. Hutton in the Salmon and Trout Magazine to which I have already 

 referred. The figures have been worked out in series of four years ending 

 in each year, with the rather surprising result that when spring fish are 

 separated from summer fish (January to May being taken as spring), a rise 

 in the supply of spring fish is found in the case of each country. The sets 

 of curves shown are quite distinct, the spring curves being steady, showing 

 a rise, and the summer curves less flat, showing a fall. Unfortunately, the 

 fall more than overbalances the rise, so that the curves showing total 

 deliveries, although they rise in 1909 and 1911, shoAV a decline over all, 

 and a marked decline since 1914. 



Since the days, in the middle of last century, when bag net fishing was 

 first introduced on the coast of Forfarshire, the netting of salmon has 

 become a more and more skilful operation. With the advent of the bag 

 nets, some fisheries in West Highland rivers failed. But these fisheries 

 were carried on by both crnive and sweep net, and no surprise was felt 

 that the stock of fish could not stand the addition of a third method. 

 It was natural, however, that the new method should be blamed. None 

 the less, the view was at length reached that bag net fishing was really 

 less harmful than cruive and sweep net fishing in these comparatively 

 small rivers, so the cruives were done away with, the sweep nets given up, 

 and the bag nets remain. 



Everyone now recognises that the general interests of any river or 

 district cannot be upheld if cruives are fished. Similarly, in Scotland 

 at least, I believe every one holds that only a moderate amount of sweep 

 netting can, with safety, be carried on in the estuaries of our largest 

 rivers. To use the net and coble by day and night in the mouth of a 

 comparatively small river simply results in the various runs of fish being 

 removed till the end of the netting season, when only a very inadequate 

 remainder can ascend to propagate their species. To secure an adequate 

 stock, it is necessary that a proportion of every run of fish should be 

 enabled to pass beyond the nets to the comparative security of the upper 

 waters. The maximum stock of salmon which any river can carry 

 depends upon the amount of food for the fry, par and smolts, before they 

 leave fresh water for the sea. 



It is quite possible that when fry are in immense numbers, as they 

 must be, for instance, in the Pacific Coast rivers of the North American 

 continent, the fry must have recourse to the sea for a sufficient supply 

 of food. Recent research shows, at least, that the fry of the Sockeye 

 descends to the sea at once, or as quickly as the enormous length of many 

 of the rivers permits. Temperature has also a great influence, no doubt, 

 in controlling the supply of food, as has been demonstrated in Norway 

 where a completely difi'erent habit seems to obtain in the southern rivers 

 from what is found in the cold rivers of Finmarken within the Arctic 

 Circle. 



Our conditions, however, seem to require that the great majority of 

 our smolts shall remain two years in fresh water before making their first 

 entrance to the sea, and we not only require the food, but we require 

 a certain amount of purity in order to enable the food to live. 



Our rivers have no doubt altered to some extent, and through the 

 great development of land drainage, floods do not last so long as formerly 



