TRANSPLANTING 83 



Special precautions are taken for the cleansing of the 

 ponds from time to time and the renewal of the water, as 

 well as for collecting the fry for shipment after they are 

 hatched. 



(See Bulletin of Michigan Fish Commission, No. 7.) 

 In a summary deduced from observation and experiment 

 by Mr. Dwight Lydell the main points are as follows: 



1. Three methods of bass propagation have been tried, — 

 artificial fertilization and hatching, pond culture, and trans- 

 ference. 



2. Artificial fertilization has been found impracticable 

 and has been abandoned. 



3. Pond culture is the method now universally employed 

 and has resulted in the following practices and devices: 



a. Ponds are now commonly built on the model of 

 the natural pond. 



b. It is the practice to have the ponds well grown 

 with vegetation. 



c. In ponds intended for small-mouthed bass it has 

 been learned that the temperature and turbidity of the 

 water are important and must be controlled. 



d. Brood fish are sorted just before the breeding 

 season, so that the males in any pond shall not be in 

 excess of the females. 



e. Brood fish are fed as far as possible on minnows. 



f. Artificial nests have been gradually evolved. The 

 earliest nests were merely gravel piles. The latest 

 forms are the shielded and screened nests of Lydell, 

 designed to afford shelter for the parent fish and a suit- 

 able material upon which to lay the eggs; gravel for the 

 small-mouthed bass and fibre for the large-mouthed. 



4. The difficulty which still remains to be overcome in 

 pond culture is the death of eggs before or soon after hatching. 



5. This death is to be attributed to lack of vigour of the 

 parent stock, and a remedy is to be sought in the following 

 directions: 



