44 FOOD FISHES 



If you open the mouth of a herring you may feel, it is true, 

 numerous small teeth, both on the tongue and sides of the 

 mouth, but these are of no great importance. If, however, 

 you lift up the gill-covers you see what at first sight looks like 

 the underside of a mushroom. These are the gills, and just 

 inside them are the white gill-rakers of the fish. If you 

 examine them carefully you will find that there are four 

 curved pieces of bone joined together at the top and bottom. 

 These are called the gill-bars. On the outside of each bar are 

 two rows of soft red gills, and on the other, or inner side, are 

 horny projections like the teeth of a comb, and each of these 

 teeth again is uneven at the edge like a saw. These are the 

 gill-rakers, and they are arranged in such a way that, when 

 the fish in breathing takes gulps of food-laden water into its 

 mouth, the food is strained out by the gill-rakers, and goes 

 into the animal's stomach, but the filtered water passes on 

 over the gills (which absorbs the oxygen dissolved in it) and 

 out again into the sea. Herrings, then, are abundant where 

 there is an abundance of food, i.e. of copepods, and the larvae 

 of the various creatures that live at the bottom of the sea, 

 and these again abound where there is food for them. 



Sometimes on the surface of the sea you notice a pinkish 

 kind of scum. This consists of myriads of tiny plants, on which 

 the microscopic animals live ; then, again, there are other 

 sea-plants like little yellow-brown rods, these are the diatoms ; 

 others, again, are globular in shape and sea-green in colour. 

 So numerous are they that in places they render the sea turbid, 

 or colour it pink or green. 



The Eggs of many kinds of fish are transparent and float 

 upon the surface of the water, but those of the herring are 

 heavy and sink. Each egg is about the six-hundredth part of 

 an inch in size, and together they form sticky masses, which, 

 when they reach the bottom, adhere to the rocks, or gravel, or 

 plants near the shore. The fish, therefore, come into shallow 

 water to spawn, and it is when they are approaching the land 

 for this purpose that they are taken in the greatest quantities. 



