MANUAL OF FISH-CULTURE. 173 



and impregnated attacli tliemselves to the floor of the nest. Then 

 commences a parental watchfulness worthy of imitation on the part of 

 some higher animals, one fish hovering immediately over the nest and 

 maintaining a gentle motion of the fins for the purpose of keeping the 

 eggs free from sediment, and the other acting as an outer sentinel, 

 patrolling 8 or 10 feet away. Both male and female show great courage 

 when guarding their eggs and young fry. A rock bass has been seen 

 to leap entirely out of the water to bite viciously at an attendant's hand 

 when mi)ving aside the grasses sheltering the nest, and a black bass 

 when guarding its nest has been known to attack and kill a snake three 

 times its own length. The brightness of the nest makes the parent on 

 guard easily distinguishable by enemies, like the fish-hawk and eagle, 

 but this danger may be materially lessened by planting the broader-leaf 

 water-lilies near the nests to afford shelter when in danger. 



Black bass begin to spawn in the northern part of the United States 

 about the middle of May, while farther south the season commences as 

 early as March, and in all localities it is later in deep than in shallow 

 waters. In the far South, in waters uniformly warm, the spawning 

 time may not depend entirely on the seasons. The period lasts about 

 two months. Many, if not all, discharge only a part of their eggs at 

 one spawning. The maturation of the entire ovaries is never fully 

 completed at one time, but the ripening is prolonged and the spawning 

 done at intervals. As far north as southern Missouri and Illinois, 

 black bass frequently spawn in the season following the sirring when 

 they are hatched, but this is not always the case; and farther north 

 maturity comes later in life. Bass continue to yield eggs for a number 

 of years, and there are some in the brood ponds at Keosho which were 

 adults when first taken to the station, and have been held for seven 

 years and are still i^roductive, though less so than formerly. 



Rock bass have been known to produce two separate broods within 

 one season as far north as southern Missouri, and this is probably true 

 of some of the other basses. At Neosho they spawn when one year old. 



EGGS AND FRY. 



The eggs differ greatly in number and size, according to the age and 

 size of the fish, varying generally from 2,000 to 10^000 i)er fish and from 

 80,000 to 100,000 per quart; 17,000 eggs have been found in a large 

 mouth black bass weighing 2^ i^ounds, a little less than 7,000 to the 

 jiound of fish; but on another occasion careful count of the mature eggs 

 showed only 2,G74 to the pound of fish. Wide discrepancies in the 

 figures maybe sometimes accounted for by di»fiferent methods of count- 

 ing, as in rejecting or counting small eggs which are commencing their 

 maturation for the next production. The rock-bass egg is fully three 

 times as large as that of the black bass, and the fry correspondingly 

 large. 



The varying factor of initial vitality and the impossibility of equal- 

 izing the intensity of sunlight render it impossible to determine r>re- 



