Dissertation Research: Physiological and Morphological Specializations for High Performance Swimming in the Mako Shark, Isurus oxyrinchus (Family Lamnidae)

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

This Dissertation Improvement Award will enhance ongoing studies on the swimming performance of the mako shark. This work will provide new information about how makos, and their close relatives, resemble tunas in features related to an elevated metabolic rate and swimming capacity. Characters unique to mako sharks and to tunas include modifications of the cardiorespiratory system, muscle morphology, elevated enzyme activities, and warm bodies. The project's objectives are to obtain data on makos using a large water tunnel treadmill used previously for tunas, and to gather laboratory based data on the structural components involved in the delivery of oxygen to the muscles used to swim. This project will address the energy requirements of makos for swimming and document the its ability to maintain a warm body temperature. This study is unprecedented in that it will use live mako sharks to measure variables that seem to be unique only to them, their close-relatives, and the tunas. The results of this study will be compared with those obtained for tunas to enhance our knowledge of the evolutionary process in fishes. This will show how organisms that have evolved independently for more than 400 million years have developed unique and almost identical characters that allow for enhanced swimming performance.