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} ,' <br />experience and energy expenditure associated with movements of individual pike. The general <br />model was parameterized for the specific physiological effects of temperature, body size, and <br />activity on growth and consumption of northern pike (Bevelheimer et al. 1985; Wahl and Stein <br />1991; Lucas et al. 1993). The bioenergetics model is a mass balance equation: <br /> <br />C~ is maximum physiological consumption which varies as a function of predator body mass <br />and temperature. Pis the proportion of Cm,~ actually consumed, with values ranging from 0 to <br />1. Growth G was obtained from field measurements; metabolism M, which includes costs of <br />standard metabolism, activity, and specific dynamic action (or heat increment, the energy used <br />to process a meal), changes as a function of body mass, temperature, and activity; and waste <br />W (egestion and excretion losses) is modeled as a constant proportion of ration. The model is <br />most commonly used to estimate the consumption rate (P*C~ required to satisfy observed <br />growth, or, conversely, to estimate growth if consumption is known. The energy density of <br />prey (calories or joules per gram wet body mass) determines the quantity of prey required to <br />satisfy a given growth rate: less prey of high energy density are required. Bioenergetics models <br />developed to date have accurately predicted consumption (within 5-15 % of field-generated <br />estimates) for largemouth bass (Rice and Cochran 1984) and salmonids (Beauchamp et al. 1989; <br />Brodeur et al. 1992; Ruggerone and Rogers 1992), but the current northern pike model <br />overestimates consumption by 32-59% when compared to field-generated estimates (Wahl and <br />Stein 1991). <br />