Date of Award

2018

Document Type

Thesis

Degree Name

Bachelors

Department

Social Sciences

First Advisor

Harley, Heidi

Area of Concentration

Biopsychology

Abstract

Dolphins produce frequency-modulated whistles with harmonic components, and these harmonics may have important implications for providing directional cues to other dolphins about a whistler's position. This study measured the active space- how far the whistles travel- of the harmonics of dolphin whistles in Sarasota Bay, FL, using an underwater transducer to play four different dolphin whistles (10-30 kHz). A hydrophone received the signals at fixed distances at three different depths (.46 m., .91 m., and 1.37 m.), up to 240 m from the speaker to measure received levels of all harmonics across different contexts. It was found that the active space varied depending upon the whistle and the strength of the whistle. The largest active space recorded was 240 m. Absorption rates for all four whistles were highest within the first 50 meters. Understanding the active space for dolphins is important because anthropogenic sound sources have been increasing in the ocean, and this noise can diminish the dolphin's active space.

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