Fish Hatchery Management - fisheries & aquaculture

N.UTRII'ION AND FEF,DING'213MONIDS (BASED ON COHO SALMON) FED TWICE EACH DAY, GIVEN AS PERCEN'T BODYAND WAIER TEMPERATURE. (SOLtnCs, ORECUN FISH AND WILDLIFE DEPARIMENTNUMBER OF FISH PER POUND90- 75- 6575 65 55554539 34'f l_2945- 39-29-25.5WATERTEM PERA-I'I] RT("l l1.51.71.92.12.22.52.72.9tJ. I3.33.53.73.u,1. t),1. I,1. iJt1.1.64.u5.05.11.31.5t.71.92.12.32.52.72.83.0il.'23.33.53.63.ttlJ.9,1. I,t.5.\.7t.2I ..11.6l.u2.02.22.:l2.52.72.tl3.03.23.33.5lJ.63.u3.94.14.5l.ll.ilI ..11.6].u2.02.22.52.7'2.93.03.23.,r3.53.73.83.9.1.1,1.i1I.0L',21.31.51.71.92.12.3'2.12.6'2.82.!)3.1:1.23.5:1. (i3.73.94.04.1L0 0.9I .l 1.0t.'2 l. l1.4 1.3l.fi 1.5l.u t.72.0 1.92.1 2.02.3 2.22.5',2.32.7 2.52.U',2.73.0 2.8:l.l 2.93.2 3.I3.4 3.23.5 lt.43.6 3.53.8 3.63.9 3.7,1.0 3.fl0.90.91.0t.2l .11.6l.uL92.1'2.',22.12.62.72. fl3.03.1:1.23.33.lr3.6401,I42434146,1849505l5253545556575u59tt0Here, -\Z equals the daily increase in length in inthes, and Z equals thelength in inches at the present time.To use this equation, an average monthly growth in inches is establishedfrom previous years' records for the same temperature. The daily increasein length is determined by dividing the average monthly growth by thenumber of days in the month. The daily growth then can be used to projectfish size to any date needed. An expected feed conversion is obtainedfrom previous hatchery records or calculated from the caloric content ofthe feed (see page 225).For example, on April 13, we have 210,000 fish on hand. Their feedingrate was last established on April 1, when fish were 20 pounds per 1,000fish, or 3.68 inches. We need to adjust the feeding rate again, knowingfrom past records that at this temperature the average length increase per