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CHAPTER TIL 



PEACTICAL MEASURES. 



THE question we have here to consider is : Can soles be made more plentiful by measures 

 which are not only possible but practicable, that is, which are sufficiently easy to be 

 carried out, when they are understood and have become familiar,, without a degree 

 of exertion and expense too great in comparison with the results gained? In 

 examining into this problem we must distinguish the two ways in which human action 

 can be applied to a valuable wild animal. One way is to keep the animal under entire 

 control by taking it into captivity : this may be called domesticating the animal, the 

 word domestication being used with a wide signification, and not necessarily implying 

 the taming of the animal. The other way is to leave the animal in perfect freedom, and 

 to increase its numbers by protecting it and promoting its reproduction. With regard 

 to the sole we will consider the latter method first. 



At present our knowledge is much too scanty to allow us at once to reach definite 

 conclusions and calculate with certainty the effects of measures which suggest them- 

 selves. We do not know exactly what proportion of soles are usually destroyed in 

 nature at different stages of their existence : the proportion which reach adult age 

 from a given number of eggs must, we know, be very small. 



We know that the " prosperity," if I may use the word, of a species depends on a 

 chain of extremely delicate relations between it and the other species of the fauna and 

 flora of its habitat : and we have reason to infer that in some cases these relations and 

 the species themselves are affected to an enormous extent by physical, i.e., meteoro- 

 logical conditions over which man has no control. In order to know how man's action 

 can increase or maintain the abundance of a species we require to know how his 

 action in the past has decreased its numbers. Professor Huxley, in the case of the 

 herring, for instance, has argued that enormous as is the number of herrings captured 

 annually on the coasts of Britain, the evidence leads to the conclusion that the 

 number destroyed by man is quite insignificant in comparison with the numbers 

 destroyed by the natural enemies of the herring by the cod and sea-birds and other 

 animals which prey upon it. And this conclusion seems to be supported by a 

 comparison of the abundance of herrings in different years. The number of herring 

 fishermen, the efficiency of their boats and nets, and the extent of their operations has 



