SALMONID^. 81 



Diseases or causes of destruction. — Under " fcliis head poaching devices will not be 

 included, but mortality or sickness otherwise induced. For many years, perhaps 

 from time immemorial, a fungus, Saprolegnia ferax (see Introduction), has existed 

 to a slight extent in fresh waters, as in our salmon rivers, but which, due to some 

 cause at present unknown, took an epidemic character in 1878. Since then it 

 has been chiefly seen in the spring of the year, in some rivers even in the autumn, 

 and although at first it appeared to be restricted to kelts or fishes in an enfeebled 

 condition, it has been lately observed to attack clean fish. The fact appears to 

 be that once this fungus has infected a fish, it may be the nucleus from which 

 infection spreads, and within twenty-four hours thousands of zoospores, which 

 may be termed minute germs or seeds provided with cilia, rendering them capable 

 of spontaneous movements, may become diffused through the water. These germs 

 arriving at a suitable spot develop into a fungus, and such a place is found in 

 a fish, where its roots strike downwards into the flesh and its free extremities 

 come to the surface, forming the white fungus appearance so distinctive of fish 

 suffering from this disease, and which proves almost invariably fatal from 

 exhaustion, irritation, or suffocation due to the organs of respiration being affected. 

 Although sea water appeal's to check and in some rare instances seems to cure the 

 disease, it is not improbable that it may only cause it to remain doraiant, so that on 

 returning to fresh waters it is again roused into activity. The following figures 

 show the virulence of this disease :— In the annual report for 1881 of the Tweed 

 district it is stated that during the last winter the number of fish that died or were 

 killed in consequence of the fungus disease was 14,627, making a total for three 

 years of 22,756. As each diseased fish is in itself a focus of infection, doubtless 

 they ought to be immediately removed from the river and buried. Salmon are 

 much affected by tape worms, Bothriocephalus, w T hich seem especially to like the 

 coecal appendages as places in which to reside : a species of Lemea also externally 

 attacks them when in the sea. They are likewise affected with other internal and 

 external pai'asites. 



In 1882 a whitling Sahno trutta, fib. weight, was captured in the Tay, and in 

 it were 300 fertile salmon ova; while Mr. Ash worth took upwards of 500 salmonoid 

 eggs from the maw of a trout. Mill-wheels not unfrequentty cause the death of 

 salmon passing beneath them, by direct blows. Obstructions to ascent and descent 

 are also secondary causes of disease, while pollutions are great sources of mortality, 

 more especially to the young fish. Smolts and even salmon are largely destroyed 

 while in the sea and estuaries by porpoises, seals, members of the cod-fish family, 

 and other marine enemies. 



As food. — These fish are highly esteemed and cannot be eaten too fresh, while in 

 selecting them care should be taken, provided there is any choice, to choose those 

 which are bright and silvery, rejecting such as are of a muddy tinge. During 

 the winter those which are out of season are dull in colour, their flesh is soft and 

 white, and the}' are wanting in flavour if dressed. If the fish is newly captured it 

 is usual, in order to set the curd, to put it into boiling instead of into cold water. 

 It may be boiled, but should be removed from the water as soon as done, or both 

 its appearance and flavour will deteriorate. It is generally dressed with cucumber 

 and anchovy, lobster, or shrimp sauce. This fish may be baked, done in slices, or 

 served in a hot or cold pudding. 



Salmon is cured in different ways as by simply drying, salting or pickling. 

 " Kippered" is well-cleansed salmon which has received several dry rubbings of 

 pepper and salt, then dried either in the air or artificially by means of the smoke 

 of peat or juniper berries. 



Habitat. — This fish ranges in the northern hemisphere between latitudes 15° 

 and 75°, and examples have even been captured as high as 80° 1ST. Lat. In the 

 Tinted States' report it is stated to range from the Polar regions to Cape Cud. 

 It extends throughout the seas and countries of Northern Europe, around the 

 British Isles, and also the Atlantic coast of France, but does not occur in rivers 

 which flow into the Mediterranean. 



It is rare in the Orkneys and Zetland (Baikie), and is found in all suitable 

 rivers of England, Scotland, Wales, and Ireland, where it has not been destroyed 

 ii. 6 



