Integration of Submersible Transect Data and High-Resolution Sonar Imagery for a Habitat-Based Groundfish Assessment of Heceta Bank, Oregon

Master of Science, Marine Resource Management, Oregon State University, Spring 2000

Graduate committee: D. Wright, A.J. Kimerling, R.W. Embley, M. Hixon

Nicole Nasby Lucas
College of Oceanic & Atmospheric Sciences, Oregon State Univ
Corvallis, OR 97331
nnasby-at-yahoo.com

Abstract.
In the face of recent declines in groundfish populations and lack of sufficient stock assessment information, a need has arisen for new methods of assessing groundfish populations. This project evaluates the integration of seafloor transect data gathered by manned submersible with high-resolution sonar imagery to produce a habitat-based stock assessment system for groundfish. The initial data sets are derived from 42 submersible dives made in 1988-1990 and an EM300 bathymetry/backscatter survey of Heceta Bank, Oregon in 1998. The submersible habitat survey investigated seafloor morphology and groundfish abundance along 30 minute transects over six predetermined stations and found a statistical relationship between habitat variability and groundfish distribution and abundance. These transects have been analyzed in a geographic information system (GIS) using dynamic segmentation to display changes in habitat along the transects. The initial phase of the project uses the submersible data in an attempt to extrapolate fish abundance within uniform habitat patches over broader areas of the bank using a classification based on the imagery. Ultimately, such approaches will allow researchers to characterize marine communities over large areas of the seafloor - a major methodological breakthrough for fisheries management and conservation.

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