I 
96 
A DIGITAL SURVEY TECHNIQUE FOR REMOTE SENSING 
OF COASTAL SCHOOLING FISH 
Gary A. Borstad, David A. Hill, Randy C. Kerr 
Lynne L. Armstrong, Brian S. Nakashima 
ABSTRACT 
One aspect of managing near-shore schooling fish stocks such as capelin (Mallotus villosus) and herring (Clupea 
harengus pallasi) is the estimation of a relative abundance index to verify annual fluctuations in stock size. We 
are developing a new digital survey technique using a newly developed Compact Airborne Spectrographic 
Imager (CASI) operating in the visible range, which when operational will be a great improvement on 
photographic or visual surveys. In this paper we show the spectral signature of schools of both species and of 
their natural background, and optimized bands for multi-spectral imaging. Simple image processing procedures 
are then used to calculate the school areas on several schools and the areas compared to those derived from 
aerial photography. Compared to aerial photography, digital remote sensing of fish schools offers several 
advantages including rapid turn around of results, digital signal processing and archiving, as well as the 
possibility of studies involving the behaviour of fish to other parameters also remotely measurable such as 
phytoplankton (via chlorophyll fluorescence or the blue/green colour), sediment concentration, oil slicks, and 
water mass boundaries.