Experimental Determination of Food Consumption of pike, Esox lucius, for Growth and Maintenance

Abstract

Under laboratory conditions simulating those in the field, there were seasonal changes in both growth and in maintenance requirements of pike (Esox lucius), which were to some extent independent of temperature. The peak maintenance requirement of about 45 mg of minnow (Phoxinus phoxinus) per gram of pike occurred in late June, followed by a decline through August and September until a fairly steady state of about 25 mg/g was reached in October. Maintenance continued at this level until April when there was a gradual rise to the June peak. The maintenance coefficient was 1.385 g per gram per annum, and there was no apparent decrease with size. Growth also reached a peak in June then declined through the rest of the summer and fall until it ceased in midwinter. Growth resumed in March, the rate gradually increasing until the June peak was reached. After maintenance requirements have been met, 1 g food produces.437 g pike when feeding is ad libitum. The maximum value of the coefficient of utilization is.485, at a level of feeding below that of maximum intake. The efficiency of utilization at the maintenance level is.476. Comparing the results with those reported for other species shows that pike have relatively low maintenance requirements and relatively high values for the conversion of food to pike substance.