. A civic biology : presented in problems. Biology; Sanitation. 240 A STUDY OF VERTEBRATES breeding places in the Connecticut River, and the salmon have been exterminated along our eastern coast within the past few decades. It is only a matter of a few years when the Western salmon will be extinct if fishing is continued at the present rate. More fish must be allowed to reach their breeding places. To do this a closed season on the rivers of two or three days out of each seven while the shad or the salmon run would do much'good. The sturgeon, the eggs of which are used in the manufacture of th
. A civic biology : presented in problems. Biology; Sanitation. 240 A STUDY OF VERTEBRATES breeding places in the Connecticut River, and the salmon have been exterminated along our eastern coast within the past few decades. It is only a matter of a few years when the Western salmon will be extinct if fishing is continued at the present rate. More fish must be allowed to reach their breeding places. To do this a closed season on the rivers of two or three days out of each seven while the shad or the salmon run would do much'good. The sturgeon, the eggs of which are used in the manufacture of the delicacy known as caviar, is an example of a fish that is almost extinct in this part of the world. Other food fish taken at the breeding season are also in danger. Artificial Propagation of Fishes. - - Fortunately, the govern- ment through the Bureau of Fisheries, and various states by wise protective laws and by artificial propagation of fishes, are be- ginning to turn the tide. Certain days of the week the salmon are allowed to pass up the Columbia unmolested. Closed breed- ing seasons protect our trout, bass, and other game fish, also the catching of fish under a certain size is pro- hibited. Many fish hatcheries, both government and state, are engaged in artificially fertilizing millions of fish eggs of various species and pro- tecting the young fry until they are of such size that they can take care of themselves, when they are placed in ponds or streams. This artificial fertilization is usually accomplished by first squeezing out the ripe eggs from a female into a pan of water; in a similar manner the milt or sperm cells are obtained, and poured over the eggs. The eggs are thus fertilized. They are then placed in re- ceptacles supplied with running water and left to develop under favorable conditions. Shortly after the egg has segmented (divided into many cells) the embryo may be seen developing on one side. Artificial fertilization of fish Please note that thes
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