588 The Animal Kingdom 



Economic Importance of Fish. — Fish have always been an im- 

 portant source of food for human beings ; even today they are playing 

 an increasingly significant role in our ever-growing needs for food for 

 our expanding population. 



When such generalizations as these are reduced to monetary values, 

 the importance of the fishing industry in our general economy becomes 

 clearer. In the year 1947, 3,819,663,000 pounds of fish (both fresh and 

 salt water) with a value of $208,568,000 were caught. With the ex- 

 pansion of the frozen food industry and improved marketing, these figures 

 are undoubtedly low for our present use. Today it is as common to find 

 choice marine fishes in the middlewestern markets as along the coasts. 



Some of the important food fish are the flounders, herrings, 

 salmon, cod, haddock, tuna, and mackerel. In the Great Lakes areas 

 the lake trout, pike, perch, and whitefish are important commercial fish. 



Not only the fish themselves are valuable items of food, but the 

 products from fish such as fish meal and oil are also important. In 

 1948, fish scrap and meal useful as fertilizer and as pet food produced 

 amounted to 199,519 tons with a value of $323,068,734. Oil, not in- 

 cluding vitamins, in 1948 amounted to 16,343,407 gallons with a value 

 of $18,475,855. Vitamins also are an important product of our fisheries; 

 in that same year, 740,137 gallons with a value of $12,507,653 were 

 produced. 



In recent years, fishing as a recreation has become increasingly 

 important. This has secondarily brought about the development of 

 recreation areas, fish hatcheries, large research units for the propagation 

 of fish and the commercial production of fishing gear. Of great interest 

 to many hobbyists is the cultivation of small aquarium fishes. 



Another use of fish that probably will gain more importance in the 

 future is their employment for the control of mosquito larvae. The top 

 minnow, Gamhiisia, has been extensively employed for this purpose and 

 has apparently been successful. 



Orders of the Class Osteichthyes. — More than 40,000 species 

 of fish are at present recognized ; these are divided into a varying 

 number of orders by different authorities, with some workers recognizing 

 more than 100 orders. Obviously it is impossible to summarize this 

 vast number of animals in any comprehensive fashion. Below, is listed 

 some of the more important orders with a few well-known repre- 

 sentatives. 



