Fish population and behavior revealed by instantaneous continental-shelf scale imaging

The application of a technique to instantaneously image and continuously monitor the abundance, spatial distribution, and behavior of fish populations over thousands of square kilometers using Ocean Acoustic Waveguide Remote Sensing (OAWRS) is demonstrated with data from its first implementation in a 2003 field experiment off the US Continental Shelf south of Long Island, NY. Conventional methods for monitoring fish populations rely on highly-localized, point measurements made from slow-moving research vessels that survey along widely spaced line transects to cover the vast ocean environments that fish inhabit and so significantly under-sample fish populations in time and space. This leads to incomplete, ambiguous and highly-aliased records of fish abundance and behavior. In contrast, OAWRS surveys at a rate roughly one million times greater than that of conventional fish-finding methods. Within a minute and a half, OAWRS images the ocean environment over more than ten thousand square kilometers, an area similar to the state of Massachusetts. This is possible because OAWRS exploits the natural capacity of the continental-shelf environment to act as a waveguide where sound waves are efficiently propagated over long ranges (tens of kilometers) via trapped modes that suffer only cylindrical spreading loss rather than the spherical spreading loss suffered in the short-range (hundreds of meters), waterborne propagation paths employed by conventional fish-finding sonar (CFFS). In this thesis, a method is developed for estimating the instantaneous population density and abundance of fish populations from wide-area OAWRS imagery.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Symonds, Deanelle T

Advisor dc:contributor.advisor

• Nicholas C. Makris.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/46492

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/46492