Publication Date

2018-02-05

Availability

Open access

Embargo Period

2018-02-05

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Marine Affairs and Policy (Marine)

Date of Defense

2017-12-20

First Committee Member

Neil Hammerschlag

Second Committee Member

Duncan J. Irschick

Third Committee Member

Maria Luisa Estevanez

Abstract

Locomotor performance, such as the speed and distance of movement, often dictates an individual’s ability to locate optimal habitat, successfully attack prey, and escape predation. An animal’s locomotor performance can be impacted by their morphological characteristics. In fish, different species with varying body shapes differ greatly in locomotor ability. While many studies have evaluated cross-species differences in the relationship between body morphology and locomotor performance, to date few studies have investigated for individual level differences, especially in natural systems involving large fishes. However, a holistic understanding of individual movement patterns is important for maintaining ecosystem diversity and function, as well as understanding evolutionary processes. This is of particular importance for apex predators, which can impact ecosystems through trophic cascades and often display a high degree of variation in movement patterns. Here, I investigated relationships between variation in individual movement performance of a marine apex predator, the tiger shark (Galeocerdo cuvier), and individual differences in morphometric aspects of body and fin shape. My null hypothesis is the scale and complexity of individual shark movement is not related to individual variation in body and fin shape. To address this hypothesis, (1) I reviewed published information on the relationship between morphology and movement in fishes and (2) I investigated the relationship between movement performance (dispersion, rate of movement, activity space, and home range) of individual tiger sharks against their morphology (pre-caudal length, caudal fin area, aspect ratio, and body condition). Data generated as a result of this thesis provides the first quantitative assessment of the potential relationship between intraspecific variation in movement performance and aspects of morphology for a large migratory fish in the wild.

Keywords

morphology; movement; shark; intraspecific variation; movement performance; body shape

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