SALMON— EARLY AND LATE RIVERS. 61 



An instance has been adduced liow a river that was originally an early one 

 was found to become a late one,* and which was considered to be a result of the 

 drainage works so extensively carried on for agricultural purposes, causing the 

 summer floods to run off in a few hours instead of in several days, as had been 

 previously the case, or else caused by other obstructions. 



Irrespective of these early rivers, so termed owing to the period at which 

 clean salmon ascend, we have the migrations of these fishes up rivers in a gravid 

 condition, and which do so solely for spawning purposes. f The secondary causes 

 which induce them to enter strea,ms have been variously defined by difEerent 

 authors,! but more especially the warmth of the water in the river as compared 

 with that in the ocean, while of two rivers that which is the least cold will 

 generally be selected, and I propose to briefly consider a few of these as to 

 whether they have an influence in certain rivers being early or late. 



Act was passed permitting the oommenoement of the close season to be varied between certain 

 limits, provided it did not begin later than November 1st. For treating all rivers in an identical 

 manner, whether clean fish were present early or late in the season, and insisting upon fishing 

 beginning or leaving off on a specified day in all, was, as illustrated by a Highland Laird, when 

 before the Salmon Commission of 1824, about " as sensible a plan as it would be to prohibit the 

 farmers of England from cutting their crops till the harvests were ready in the Highlands." 



* The Earl of Home, in 1837 observed "that in the Tweed a very great change had taken 

 place within these twenty or thirty years ; a considerable portion of the breeding fish not arriving 

 into breeding condition until long after the time they had formerly been in the habit of doing so." 

 The first inquiry here should be whether this had happened consequent upon any changes in the 

 river, the placing of artificial obstructions in its course, or an alteration in the natural spawning 

 time in the fish irrespective of -the condition of the water. The river itself, it was observed, "had 

 changed, due to the draining of the sheep farms on the hiUs, the effect produced being that a little 

 summer fiood which, previous to 1795, took a fortnight or three weeks to run off, now (in 1837) 

 became completely run out in eight hours. The bogs on the hiU sides, which were the feeders 

 to the river, have the water at once carried off by drains, causing sudden but short floods, which 

 have all run off before the river has had time to clear itself." Sir H. Davy compared the Tweed 

 district as it was prior to these drains, to what it had become subsequent to their construction — 

 to two houses, the one covered with thatch, and the other with slate ; the first dripping for hours 

 after the rain has fallen, the other ceasing when the rain stops. 



f Professor Huxley (Report of H.M. Inspector of Fisheries, 1884, page 26) suggested that 

 " we may call the interval between the ascent of the earliest and that of the latest fish in 

 any given river the ' anadromous period ' of the river." But however applicable such a designa- 

 tion might at first sight appear, very strong objections must occur to restricting such a term to 

 migrations of anadromous Sahnonidse. In some rivers these fish only ascend during the spawning 

 time, while char migrate at the same season for breeding purposes, from the depths of lakes or 

 large pieces of water, to suitable streams and shallows, in order to deposit their ova and milt ; 

 and this time with the char would be as completely their " anadromous period " as when similar 

 conditions in the salmon caused simUar movements ; but char are not usually considered to be 

 anadromous forms : even carps in Asia similarly migrate at spawning time, as well as many 

 other fish, and to term such migrations " anadromous periods " in some fish and not in others 

 would clearly be erroneous. 



J James Gillies deposed in 1824 respecting the Tay, where he had fished for twenty-six 

 years, that " when I first went to Perth, most of the river was over with spawning in December, 

 but you will now scarcely see one fish come there to the redd, tUl about the end of November, 

 and the spring time for spawning is generally in the months of December and January." 



Mr. Buist (1832) stated that, " from his own observation or from the testimony of others who 

 have had opportunities to observe it very minutely, that the fish begins to spawn about the middle 

 of October and continue untU about the end of January." 



The Commissioners appointed in 1861 to investigate the Salmon Fisheries of England and 

 Wales came to the conclusion that, " the great breeding season in England and Wales of all fish 

 of the salmon kind is in the months of November, December, and January .... and believe it 

 will not vary more than a fortnight in any river .... in some seasons it may commence a little 

 earlier, or be continued a little later, but the principal breeding operations are performed chiefly 

 iu the three months mentioned." 



Yarrell considered that "rivers issuing from large lakes afford early salmon, the waters 

 having been purified by deposition in the lakes ; on the other hand, rivers swollen by melting 

 snows in the spring months are later in their season of producing fish, and yield their supply 

 when the lake rivers are beginning to fail." The general impression seems to have been that the 

 temperature of the river water exercised some influence in acting upon the time at which they 

 were ascended by salmon when desirous of entering for breeding purposes, they usually first 

 selecting such as were the warmest. 



Dr. HeysJiam was of opinion that in Cumberland salmon at first spawn in the warmer streams, 

 leaving the snow-fed ones until later on; consequently, during the winter and spring, they 



