Date Presented

Spring 4-17-2019

Document Type

Thesis

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Dr. Takashi Maie

Second Advisor

Dr. Nancy Cowden

Third Advisor

Dr. Jason Crumpton

Abstract

Northern pike (Esox lucius) is an esocid species in freshwater that is highly piscivorous and grows tremendously large during ontogeny. In this study, we examined feeding morphology and biomechanics of E. lucius. More specifically, we used morphometrics on the feeding apparatus to yield a three-dimensional mathematical model that was combined with a direct measurement of buccal volume and kinematics during feeding. We evaluated feeding capacity of the fish; we examined ontogenetic scaling patterns of the feeding apparatus and prey-capture capacity in E. lucius. In addition, this project tested hypotheses regarding how morphological components of the feeding apparatus (e.g., lever ratio) in E. lucius change as the fish grow in size and how its prey capture performance capacity changes during ontogeny. By conducting this project, we aimed to evaluate functional morphology that contributes to Northern Pike feeding-performance capacity in relation to functional demands for capturing prey that the predator fish experiences in its habitat. By using a conical frustum model, we were able to calculate an estimated buccal volume change for each of our E. lucius specimens. The frustum model was found to overestimate the actual volume change by 37% for our largest subject. The total head lengths of our specimens were 16.98cm, 8.24cm, and 8.67 cm, and we found suction flow values of 375cm/s, 199cm/s, and 237cm/s respectively. Comparing these values to previously studied centrarchid fishes (largemouth bass and bluegill sunfish), our E. lucius showed much greater suction feeding performance. While our sample size was too small to perform a statistical analysis to compare our findings, these results support that E. lucius has greater suction-feeding performance than other fish species using the same feeding mode, allowing it to be a more successful freshwater predator.

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