CHAPTER XL 



POND LIFE. 



Water full of life Care required in dealing with it The rotijera Rul 

 .for cultivation Natures provision for young fishDaphnia pulex Cyclops 

 quadricornis Cypris tristriata Arachnida Notonecta Corixa Gammarus 

 Dytiscus Caddis worms Ephemera Shellfish Parasites Saprolegn ia. 



\A7HEN any important fish-cultural question requires to be 

 answered, the safest and surest way of getting sound 

 information on the subject is to send a thoroughly competent 

 expert to make a careful examination into all the details of the 

 case. This is the way to arrive at some really definite conclusion, 

 and obtain a correct verdict. There are so many who are ready 

 to denounce as hopeless anything that they themselves cannot 

 understand or do, that if we listen to their cries nothing would 

 ever be accomplished. Nearly every section of fish culture has its 

 opponents, and but for the persevering efforts of a few individuals 

 nothing would yet have been done towards cultivating the waters 

 of the British Isles. 



The important subject to which I am in this chapter about 

 briefly to allude, is one that is now engaging the attention of men 

 of science, who have had their attention drawn to the great 

 importance of its bearing on the welfare of our fisheries. At 

 certain times of the year some of our waters are found to contain 

 an enormous mass of living organisms, and we will now consider 

 a few of these beings which inhabit our ponds and lakes, or their 

 margins, with a view to the utilization or otherwise of the supply 

 of fish food which Nature has already provided. 



The subject is an exceedingly wide one, and it is necessary 

 at the outset to use caution in the course of our investigations, 

 for we have not got very far before we find that we have enemies 



