72 SALMONIDJE OF BRITAIN. 



estuaries, but likewise along the sea coast, whicli -would seem to show that some 

 effect had been produced which induced these fish to press onward toward the 

 spawning beds.* 



Bad takes in a given year may be often due to causes which have acted 

 generally upon the fishes, or else been locally detrimental to their appearance off 

 the coast, or to their entering estuaries or ascending rivers ; while on the other 

 hand a good season may be mainly owing to a successful breeding season three or 

 four years previously. It has been observed by Dr. Murie that in the year 1867 

 there was a general absence of grilse throughout the waters of Great Britain, and 

 in 1885 H.M. Inspector of Fisheries observed " that it is remarkable that while so 

 large a run of grilse was obtained in the Tyne on the east coast, this description of 

 fish was exceptionally rare in the rivers of the Bristol Channel on the west 

 coast, "t 



During their migrations up river these fish have to overcome many obstruc- 

 tions, whether natural obstacles or artificial impediments, as weirs, and frequently 

 these can only be surmounted during a heavy flood. While in the Severn, although 

 salmon ascend every tide, the shoals seem to do so mainly during the six or eight 

 spring tides preceding and following the highest spring, while the most do so just 

 prior to the highest tide. If the water in any river is very low, possibly the pools 

 would contain no safe resting places for ascending salmon, and spring fish would 

 be very unlikely to accomplish their ascent, for they would most probably be 

 captured by man or destroyed by vermin. J 



It has been observed by Mr. Willis-Bund (Salmon Problems) that supposing 

 a clean fish were interrupted in its journey up stream in fresh water, it drops back. 

 Thus, he remarked that a poacher who has missed gaffing a fish, first looks for 

 his lost game in the pool below, not in the one above. It has also been observed 

 of the Californian salmon, that when a rack is placed across a river the unripe fish 

 drop back. In November, 1885, with the aid of Sir J. Maitland, we investigated 

 this on a small scale in the Teith, and when netting salmon for the purpose of 

 obtaining ova, so far as was practicable, each fish on being returned into the 

 river, had an elastic band slipped over its tail ; and out of eight shots with the 

 net, and a total take of forty-three fish, three of which were clean, we only 

 recaptured one marked specimen. We worked down stream, except for the last 

 two shots, and it was at shot No. 7 that the marked fish was taken. Conse- 

 quently it would appear that spawning fish, when captured below where they 



* In the Birmingham Daily Post, July 17th, 1882, it was stated that " for the last ten days, 

 owing to the heavy rains, the takes of salmon in the principal Scotch rivers have been extra- 

 ordinarily large, and the stake net fishing on the sea coast has also been unusually productive. 

 On Tuesday, on a stretch of coast not longer than eight miles, between Montrose and Bervie, 

 from seven to eight tons of salmon, grilse, and trout were landed, and were at once despatched 

 to the southern markets." 



f Mr. WiUis-Bund (Field, August 7th, 1886) remarked, with 'reference to the laws which 

 regulate the migration of fish in connection with weather, that a good year for one kind of 

 anadromous fish in our waters is usually also a good year for the other kinds, while if it is a bad 

 season for one kind, it is usually a bad season for aU. It therefore seemed to follow that the 

 same cause which leads to a large migration of one kind of fish wiU produce a large migration of 

 the other kinds, always opining that the stock of each kind of fish is kept up in the same propor- 

 tion. Isolated migratory salmon ascend on almost every tide, but the shoals in the Severn only on 

 spring tides, and mainly on the six or eight spring tides preceding and following the highest 

 spring, while the largest is just before the highest tide. At the very highest tide there appears to 

 be a partial or entire cessation of migration (but on other rivers this is said not to be so) : more 

 fish run during the change from neap to spring than during the change from spring to neap, while 

 a series of high spring tides generally give a larger run of fish than a series of moderate spring 

 tides. Anglers are aware that with a falling barometer fish usually will not rise ; it may be 

 because they are moving. The different elements in the Severn required to bring about a good 

 run of fish are the following : (1) A high spring tide ; (2) S.W. wind ; (3) higher temperature 

 of water in the estuary than the land water in the river ; (4) low but steadily rising barometer 

 to a height of 29° 50' ; and (5) moderate rise of land water. The result of an examination of the 

 four types of weather leads to a conclusion that fish run better during weather of a southerly or 

 westerly type than they do when the weather is northerly or easterly. 



J Dr. Brookes, Art of Angling, 1799, observed, " where the salmons have not dams to stop 

 them they wiU change the salt for the fresh water several times during the summer " (p. 150): and 

 Dr. Giinther believes that a salmon changing from salt to fresh water, and vice versa, several 

 times in the year, only occurs in rivers falling into the Moray Firth. 



