Development and Corroboration of a Bioenergetics Model for Northern Pikeminnow211 ('Ptychocheilus oregonensis') Feeding on Juvenile Salmonids in the Columbia River

摘要

A bioenergetics model was developed for nothern pikeminnow Ptychochelius211u001eoregonensis, an important predator on juvenile salmonids in the Pacific 211u001eNorthwest. Predictions of modeled predation rate on salmonids were compared to 211u001efield data from these areas of John Day Reservoir (Columbia River). To make model 211u001eestimates of predation rate, three methods were used to approximate the change in 211u001eweight of average predators during two-month periods: observed change in weight 211u001ebetween the first and the second month, predicted change in weight using seasonal 211u001egrowth rates, and predicted change in weight using an annual growth model. 211u001eCombining all reservoir areas, the model predictions of predation on salmon were 211u001eless than comparable field estimates using the observed weights (-19%), the 211u001eseasonal growth rates (-45%), and the annual growth model (-15%).