[7j FEESHWATER FISHERIES OF ICELAND. 329 



shallow and contains but few fish, while the southern and eastern part 

 is deeper. In this southern part I found a depth of 3 J fathoms, and it 

 was comparatively rich in fish. From these preliminary remarks a 

 tolerably correct idea of the character of this lake is gained. I should 

 state that the only kinds of fish which were observed were the trout, 

 the mountain-trout, and a variety of the sticklebacks. 



From all reports it appears that the Myvatn Lake was richer in fish 

 in former times than it is now, but I am inclined to think that the 

 persons who made these reports were mistaken. It is surprising to see 

 how little the Icelanders themselves know about the natural conditions 

 of places whicii they see every day ; and many of these conditions are 

 not rightly understood, simply from lack of sufficient knowledge. As 

 a cause of the decrease in the number of fish it was mentioned that 

 there were in the northern and western portions of the lake many small 

 particles of clay, whicli were said to have become detached from the 

 bottom through the influence of heat, and which made the water muddy 

 and killed the fish by adhering to their gills. It is true that the water 

 in many places was very muddy ; but this was not caused by small 

 particles of clay, but by the spores of a slimy sponge which was " bloom- 

 ing " at the time. The mountain-trout are said to have suffered particu- 

 larly ; and I was informed that during the warm summer of 1880 many 

 fish died. I was told that under these circumstances the fish came near 

 the shore. The fish seem to prefer the east side of the lake, and the 

 natural cause is this, that in this portion numerous little streams flow 

 into the lake from the lava, whose water is purer and cooler than that 

 of the lake. In winter these streams are comparatively warm, at least 

 compared with the water of the shallow lake ; and it is, therefore, 

 natural that the fish like to spawn here. Here also they are principally 

 caught. The fisheries are carried on with large nets or pieces of nets 

 which are spread before indentations in the shore and also farther out. 



In examining the northwestern, northeastern, and northern portions 

 of the lake I found it on an average only 2 feet deep. In the eastern' 

 portion, where most lava blocks are found, there are large holes in the 

 bottom 6 or 8 feet deep. In the shallow places, where the oars con- 

 tinually touch the bottom, it is composed of a soft, dark mud having a 

 bad odor, and covered with a lighter grayish-yellow layer formed by 

 the excrements of various animals. Here and there are patches of mil- 

 foil {Achillea millefolium), water-plantain {Alisma), and a few other 

 aquatic plants. These patches of vegetation hide a rich animal life, 

 such as the larvae of flies, small crustaceans, and in the upper layer of 

 mud small mussels. Gulls, ducks, and their young find a rich supply 

 of food among these aquatic plants. As a general rule the water is tol- 

 erably clear, but in spite of this I could not discover a single fish during 

 my trips across the waters of this lake. It is probable that the shallow, 

 clear water, tbe muddy bottom, and the numerous birds keep the fish 

 away. I was told that most of the fish caught in this part of the lake 



