and fingerlings will have a chance to grow and 

 reach the ocean, and later return to the spawning 

 gronnds. 



In addition to raising cold-water fish for stock- 

 ing, Federal hatcheries also raise warm-water fish. 

 Let's go over and visit the warm-water ponds. 

 Watch your step as we go out on the dikes between 

 the ponds. If you should fall in, you wouldn't 

 find the water very cold. These 1-acre earthen 

 ponds have water with temperatures between 50° 

 and 90° F. most of the year. We let in only 

 enough water to keep the ponds as deep as we want 

 them. At the deepest end the water is generally 

 6 feet, and at the shallowest end it is 2 to 21/4 feet, 

 with intermediate depths in between. 



Our black bass, bluegills, channel catfish, 

 crappie, redear sunfish, and other warm-water 

 fishes get most of their food from the ponds. This 

 food is a series of living forms, a chain in which 

 each link is a plant or animal form that supports 

 another, higher form. In these ponds, the com- 



bination of rich earth, water, sun, and air produces 

 great numbers of plants that are so small they can 

 be seen only with a microscope. These tiny plants 

 are the food of the very small animals. The small 

 plants and animals are the food of insects and 

 newly hatched fish. And all are food for larger 

 insects and small fish like bluegills and other sun- 

 fishes. Finally, these small fi.sh are the jireferred 

 food of the large bass, crappie, and catfish. Weeks 

 before the nesting season begins, we put fertilizer 

 (manure or various chemicals) into the ponds to 

 assure a good growth of the tiny plants that are 

 the first link in the food chain. 



Here is a pond full of bluegills, including adults 

 (large fisli) , fingerlings, and fry. Wien the water 

 temperature is almost 70° F., we put (>0 to 100 

 adults into a pond like this. On the bottom, the 

 male bluegills brush out nests. They build these 

 nests in groujjs or colonies, and each male protects 

 his own nest from intruders. When the water gets 

 a little warmer, the fish spawn over these nests. 



A FISH FOOD CHAIN 







"^orot^"^ 



