;96 Fish and Game Warden. [Bull. No. 1. 



The Male Guards the Nest. 



The male fish guards the nest and eggs during the greater 

 part of the period of incubation, so to speak, and is now more 

 pugnacious than ever. He will fight anything that comes in 

 his dooryard, and is very active and very busy flying around 

 from place to place. When he is not annoyed by intruders he 

 spends much of his time over the nest, his fins continually 

 moving, in order that fresh currents of water may continue to 

 flow over the eggs and prevent any sediment from settling 

 upon them. This great vigilance and activity on the part of 

 the male fish is kept up until the eggs hatch. The period of in- 

 cubation depends largely upon the temperature of the water. 

 Three years ago we marked a nest where fish were spawning 

 and visited it regularly every day. It was in early springtime, 

 and was one of the first nests we observed. The water was 

 cold and it took fifteen days for the eggs to hatch, and only a 

 small per cent (we should judge about 10 per cent) of them 

 hatched. Many of the eggs, for one reason or another, disap- 

 peared. The eggs that were lost from this and some other 

 nests that we were watching disappeared apparently during 

 the nighttime. We were not able to discover the cause of 

 their disappearance. Some of the eggs turned white, due to 

 fungus growths. Another nest that we marked later in the 

 season came off, so to speak, in twelve days ; and another still 

 later in the season hatched in seven days. We found one this 

 spring which, if no mistake was made in the day when the 

 eggs were deposited, hatched in five days. This was in the 

 latter part of May, when the water was warm and all condi- 

 tions most favorable. 



The Young Fish, or Fry. 



When the eggs first hatch, the little fish, with head and tail 

 free and the yolk of the egg attached to the body, remain in 

 the nest close to the bottom, but they soon (in two or three 

 days) begin to move around more or less, rising above the nest 

 and spreading out. At this time the parent fish is very active 

 and very pugnacious, and will fight almost anything that comes 

 near the nest. They sometimes get so bold that they will grab 

 at one's hand if it is placed in the water near the young brood 

 or school of fish. As the young fish, or fry,* grow older they 

 move about more and more, and rise up nearer and nearer to 

 the surface of the water. The old fish is still very vigilant, and 

 will chase a minnow or any other fish that happens to come 

 near to this school or family of baby fish. We have wondered 

 time and again how these old or parent fish could keep up such 

 a continuous warfare, without any apparent rest, for days and 

 days for the care of the young fish. 



* For explanation of the term "fry," see page 133. 



