134 'J'lilrli/'si.rll, Annual Mrvlnnj 



}yal('r !>uj)iily. — Tlic walcr su])|)ly of the lisli-i)Oiid is the 

 most impoi-lanl tliiii.y lo be coiisiilerod. It must in fact be taken 

 into consideration lu'lon' ilie artificial pond is made. The flow 

 of water slioidd he aliiindaiit. Ahoiit twice as much will usually 

 be required as Ihc hi'^iniicr lhiid\s is ncccssarv. Ponds led by 

 strong si)riii,iis ai'c excellent and are not subject to the dangers 

 to which stream-fed ponds are exposed. Their temijerature is 

 naturally more equable throughout the year and they are less 

 liable to heavy freezing in winter. In warm weather and in the 

 winter time, pond-fishes avoid extreme temperature by frequent- 

 ing the vicinity of bottom springs. Spring-water, however, con- 

 tains less life available as fish food, and less air than that from 

 brooks. Its value for pond supply will be improved, if it can be 

 led some distance as a rivulet. Fish-life in small ponds with 

 limited water supply will suffer from heavy ice in winter. The 

 ice should be l)roken daily, and masses of brush and branches 

 placed partly in the water will aid in keeping air holes open, 

 especially if they are moved by the wind. 



Extent and Depth of Ponds. — The extent and depth of ponds 

 made by damming streams, Avill be governed somewhat by the 

 nature of the situation available. A pond of an acre or more in 

 extent, and with eight or ten feet of water in the deepest part, 

 will, if ])r()])erly managed, give excellent results. It may be 

 necessary to nialce it less than one quarter of an acre in extent, 

 but a small pond should have an extreme depth of not less than 

 six feet, although it is quite possible with a strong water supply 

 to raise fishes in very small and shallow ponds. This, however, 

 means active cultivation, with daily feeding of the fishes, num- 

 erous ponds to permit of sorting, and all the details of a fish- 

 cultural establishment. As a matter of fact, nearly all of ihi' 

 extensive fish-breeding carried on by the national and state fisii 

 commissions has been done in ponds of rectangular shape, av- 

 eraging perhai)s less than 100 feet in length and 2~i feet in 

 width, having depths of only three or four feet. Such pond< 

 are workc*! in series, as nursery and reai'iiig ])onds. and there are 

 generally two or more ])onds of lai'ge size in wliicli fislies of dif- 

 ferent growths can he held. Toiids to be used for black liass 

 and in fact most other llsbes. ougbt to be sevei'al acres in extenr 

 and ouite deei). Ill iz'eneral. lisbes kci)t in small ponds do not 



