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Title: Use of Aerial Photography to Monitor Fall Chinook Salmon Spawning in the Columbia River

Journal Article · · Transactions of the American Fisheries Society

This paper compares two methods for enumerating salmon redds and their application to monitoring spawning activity. Aerial photographs of fall chinook salmon spawning areas in the Hanford Reach of the Columbia River were digitized and mapped using Geographic Information Systems (GIS) techniques in 1994 and 1995 as part of an annual assessment of the population. The number of visible redds from these photographs were compared to counts obtained from visual surveys with fixed wing aircraft. The proportion of the total redds within each of five general survey areas was similar for the two monitoring techniques. However, the total number of redds based on aerial photographs was 2.2 and 3.0 times higher than those observed during visual surveys for 1994 and 1995, respectively. The divergence in redd counts was most evident near peak spawning activity when the number of redds within individual spawning clusters exceeded 500. Aerial photography improved our ability to monitor numbers of visible salmon redds and to quantify habitat use.

Research Organization:
Pacific Northwest National Lab., Richland, WA (US)
Sponsoring Organization:
US Department of Energy (US)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
15002638
Report Number(s):
PNNL-SA-36520; TAFSAI; EW02J1370; TRN: US200416%%165
Journal Information:
Transactions of the American Fisheries Society, Vol. 131, Issue 6; Other Information: PBD: 1 Nov 2002; ISSN 0002-8487
Country of Publication:
United States
Language:
English