212 SALMONIDiE OF BRITAIN. 



Similarly in Wales, it has been found that the great increase in the numbers of 

 fly.fishers has been coincident with decreased size of flies and diminished baskets 

 of fish. In some pieces of water one sees thousands of small trout and no large 

 ones, and it would seem as if the general size is such that they are unable to 

 prey upon one another ; consequently, all starve together.* 



For good fishing, it is necessary to have a good breed of trout and plenty of 

 food. If there is a large stock by consuming the food and producing a famine, 

 some, if not all, must be kept out of condition ; and in such cases it is necessary 

 either to increase the food or decrease the stock. While pike in waters will often 

 prevent trout feeding : even large trout of a kelt-like form may be as injurious as 

 pike by eating the smaller fish. Streams coming from a limestone formation and 

 high hills, generally give smaller fish than those which pass over rich meadows, 

 where the water is warmer and the food superior. 



It has been observed in Germany, that young trout thrive best in natural 

 streams for the first six months of their lives, and subsequently best in trout 

 ponds from 5 to 10 feet deep, and ^ to f of an acre in extent. Shallowest at the 

 inlet to allow the water-weeds to grow and thus furnish animal life ; deepest at 

 the other end to permit the temperature to be low (see Fishing Gazette, May 8th, 

 1886). 



That the existence of places in a clear stream where trout can conceal themselves 

 are almost a necessity, must be admitted by every fisherman. The wave of a fishing 

 rod, the appearance of some unusual phenomena will make the fish either rush 

 to their accustomed haven of security, or dash away to and alarm the shoal. 

 Also, when from some cause, as a miller cutting the weed, these hides have been 

 destroyed or are deficient in a stream, an angler has but little chance of making a 

 capture, and as a result, the trout increase in numbers more than in size. The 

 following plan has been found by Mr. Francis in some streams to prove efiicacious : 

 nail some inch deal boards, 7 feet long, to three cross pieces of ash, G feet long, 

 and three inches by two inches, making a kind of table 7 feet by 6. Then drive 

 four plugs into the centre of the stream about 5 feet apart, square, and standing 

 eight inches from the bottom. The table to be nailed to the plugs. 



Many of the agencies which destroy the ova or young of these fishes have been 

 detailed (pp. 28, 45, &c.). Robins, hedge-sparrows and water ousels are not 

 harmless, but have been observed carrying ofi' eggs and young fish (Beresford, 

 Fidd, July 2nd, 1884), the wagtail has likewise been accused of the same practices. 

 In the United States, mosquitoesf have been observed killing young fish, while an 

 external parasite, Argidus foliacceus, is not rare in our fresh waters, and is also 

 destructive. In some places I liave known the bed of the stream, when the Avater 

 has been run off, absolutely swarming with bull-heads, Cott^is gohio, which fish are 

 most destructive to young trout. 



Mr. Hutton, Fishing Gazette, July 17th, 1886, gave an account of seeing in the 

 backwater of the Dove, a trout of about 1 lb. struggling with an eel 8 or 9 inches 



* Mr. Francis, Fishing Gazette, July 10th, 1886, observed that "in Llyn Ogwyn years ago, from 

 May to September, a good hand on any fair day might take from three dozen to four dozen vigorous 

 red-fieshed trout, averaging about 10 oz." Twenty-five years later he found baby trout, due to the 

 owner ceasing a practice long in existence of periodically netting the shallow end of the lake, 

 as a result of which, the trout have multiplied beyond proper limits, causing a disproportion. 



t A recent Bullet ill of the United States Fish Commissioii contains the following: — "In the 

 middle or latter part of June, 1882, 1 was prospecting on the head Avaters of the Tumichie Creek, 

 in the Gunnison Valley, Colorado. About nine o'clock in the morning I sat down in the shade 

 of some willows that skirted a clear but shallow place in the creek. In a quiet part of the water, 

 where their movements were readily discernible, were some fresh-hatched brook or mountain 

 trout, and circling about over the water was a small swarm of mosquitoes. Every few minutes 

 these baby trout^for what purpose I do not know, unless to get the benefit of more air — would 

 come to the surface of the water, so that the top of the head was level with the surface. When 

 this was the case a mosquito would light down and immediately transfix the trout by inserting its 

 proboscis, or bill, into the brain of the fish, which seemed incapable of escaping. The mosquito 

 would hold its victim steadily until it had extracted all the life juices, and when this was accom- 

 phshed it would fly away, and the dead trout would turn over on its back and float down the 

 stream. In half an hour, over twenty trout were sucked dry, and their lifeless bodies floated 

 away with the current." 



