Department of Marine Sciences

Hydroacoustic Technology

(1) General

School:	Of the Environment
Academic Unit:	Department of Marine Sciences
Level of studies:	Undergraduate
Course Code:	191ΕΩ14Ε	Semester:	F
Course Title:	Hydroacoustic Technology
Independent Teaching Activities		Weekly Teaching Hours	Credits
Lectures		3
		Total credits	5
Course Type:	Skills development
Prerequisite Courses:	No
Language of Instruction and Examinations:	Greek
Is the course offered to Erasmus students:	No
Course Website (Url):	https://www.mar.aegean.gr/index.php?lang=en&lesson=1076&pg=3.1.1

(2) Learning Outcomes

Learning Outcomes

The course provides students with an understanding of the physics involved in underwater acoustics, and a sound knowledge of the acoustic technology and methods applied for studying marine biological resources and their and habitats. Special emphasis is given on fisheries acoustics, as well as on passive acoustic methods used for the study and monitoring of marine mammals and underwater ambient noise. Upon successful completion of this course, students will:

Understand the physics and propagation characteristics of underwater sound,
Have a sound knowledge of underwater acoustics and related applications in marine ecology,
Be able to assess, choose, and apply the appropriate methods and tools for fish stock assessment, underwater ambient noise monitoring, and the study of marine biota and habitats by means of underwater acoustics.

General Competences

Search for, analysis and synthesis of data and information, with the use of the necessary technology.
Decision-making.
Working independently.
Respect for the natural environment.
Production of free, creative and inductive thinking.
Working in an interdisciplinary environment.

(3) Syllabus

The course covers three main aspects of underwater acoustic applications in marine ecology: (a) introduction to underwater acoustics, (b) marine bioacoustics, (c) fisheries acoustics, covering the following topics:

Introduction to underwater acoustics, historical background, introduction to main terms and symbols.
Wave theory, sound intensity, pressure and power, decibels (dB).
Propagation of underwater sound underwater, sound speed profile, reflection, transmission loss (absorption and spherical/cylindrical spreading), the sonar equation.
Marine bioacoustics, passive acoustic instruments, hydrophone types and applications, hydrophone sensitivity, signal digitization, producing a spectrogram.
Natural and anthropogenic sources of sound in the sea, underwater ambient noise, types and mechanisms of biological sound production, sound usage by marine mammals, echolocation, audiogram.
Bioacoustic measurements, in situ monitoring methods, interpreting a spectrogram, extraction of sound descriptors from a spectrogram, analysis of underwater ambient sound, marine mammal source level measurement.
Principles of operation of scientific echosounders: the acoustic transducer, beam pattern, near field effects.
Insonification, acoustic pulse, echosounder resolution, echosounder components, time varied gain (TVG).
Types of active acoustic instruments and operational examples: single beam and split-beam echosounders, multi-beam sonars, side scan sonars, ADCP, multi-frequency echosounders, description and interpretation of echograms per instrument type.
Case studies: analysis of methods and results from international research projects related to active and passive acoustics.

(4) Teaching and Learning Methods - Evaluation

Delivery:

Face-to-face

Use of Information and Communication Technology:

Multimedia use.
Use of specialized acoustic software.
Teaching support via the e-class platform.
Communication via e-class and e-mail.

Teaching Methods:

	Activity	Semester workload
	Lectures	39
	Independent study	80
	Lectures	3
	Final exam	3
	*Course total*	125

Student Performance Evaluation:

The final evaluation is a result of the intermediate exams (30%) and the final exams (70%). Both exams consist of:

- multiple choice questions

- short-answer questions

Evaluation criteria are available at the e-class platform.
Students with learning difficulties are tested orally.
Language of evaluation: Greek.
All evaluation results are announced at e-class, and students are encouraged to review their written tests.

(5) Attached Bibliography

Suggested bibliography

Simmonds, J., and MacLennan, D. 2005. Fisheries Acoustics, 2nd edn. Chapman & Hall, London.
Au, W.W.L., and Hastings, M.C. 2008. Principles of Marine Bioacoustics. Springer, New York.
Trygonis, V. 2020. Underwater acoustics. Lecture notes (in Greek). Department of Marine Sciences, University of the Aegean.
Georgakarakos, S. 2004. Hydroacoustic technology (in Greek). Department of Marine Sciences, University of the aegean.

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