HATCHERY REQUIREMENTS 55 



3,000,000 fry in the hatchery. Final release in this example calls for 

 1,000,000, 2:7-inch fingerlings. Determine the date fish will reach this size. 

 A search of the literature indicates that fry begin feeding at a length of 0.2 

 inch. By a method described in Chapter 2, the growth is projected; the fish 

 will average 2.6 inches on June 15. (For convenience, all releases have been 

 assumed to fall on either the first or fifteenth of a month.) 



(3) Determine weight. Fish lengths can be converted to pounds from the 

 length/weight tables provided in Appendix I. 



(4) Determine the number of fish or eggs required to attain desired production. 

 For example, to determine requirements on June 1 for a release of 

 1,000,000 on June 15, use one-half the monthly anticipated mortality (7.5% 

 in our example). Convert this to survival: 100% — 7.5% = 92.5%, or 0.925. 

 Divide the required number of fish at the end of the period by this survival 

 to determine the fish needed on June 1: 1,000,000-0.925= 1,081,000. This 

 can be rounded to 1.1 million for planning purposes. 



(5) Determine total weight. Total weight is determined by multiplying 

 weight per fish (Appendix l) by the number of fish on that date. 



(6) Determine flow requirements. Adequate biological criteria must be 

 developed for the species of fish being programmed before flow rates can 

 be calculated. For this example a value of 1 gallon per minute per 10 

 pounds of fish was used. Because there is a total weight of 3,850 pounds, 

 3,850^10 = 385 gallons per minute are required. Flow requirements for in- 

 cubation are based upon 1 gallon per minute per jar. 



(7) Determine rearing space. All density determinations follow the same 

 method described for Density Index determinations in Chapter 2. Biologi- 

 cal criteria must be developed for each species of fish being programmed. 



Bibliography 



American Public Health Association, American Water Works Association, and Water Pollu- 

 tion Control Federation, 1971. Standard methods for the examination of water and 

 wastewater, 13th edition. American Public Health Association, Washington, D.C. 874 



P- 



Andrews, James W., Lee H. Knight, and Takeshi Mural 1972. Temperature requirements 

 for high density rearing of channel catfish from fingerling to market size. Progressive 

 Fish-Culturist 34(4):240-241. 



Banks, Joe L., Laurie G. Fowler, and Joseph W. Elliott. 1971. Effects of rearing tem- 

 perature on growth, body form, and hematology of fall chinook fingerlings. Progressive 

 Fish-Culturist 33(l):20-26. 



Baummer, John C, Jr., and L. D. Jensen. 1969. Removal of ammonia from aquarium water 

 by chlorination and activated carbon. Presented at the 15th Annual Professional 

 Aquarium Symposium of the American Society of Ichthyologists and Herpetologists. 



Bonn, Edward W., Willl\m M. Bailey, Jack D. Bavless, Kim E. Erickson, and Robert 

 E. Stevens. 197fi. Guidelines for striped bass culture. Striped Bass Committee, South- 

 ern Division, American Fisheries Society. 103 p. 



