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Corvallis Research Lab
Fish Scales



The Fish Life History Analysis Project (FLHAP) – formerly known as the “Scale Analysis Project” – maintains high standards of quality in estimation of life history parameters of fishes, including accuracy, precision and efficiency from sample and data handling through age estimations and other life history analyses and data dissemination.  We have the trained personnel and equipment necessary to respond to management needs.



The FLHAP is part of the Western Oregon Research and Monitoring Program within the Northwest Region.  The FLHAP provides technical support within this program and to other programs, research projects and management districts within the Oregon Department of Fish and Wildlife.  Work is done primarily on scales from salmonids, with occasional work on scales from warm water fishes.  The FLHAP analyzes fish scales to provide estimations of age composition, hatchery or wild origin, growth information and other life history data as needed.  Scale samples come from spawning ground and creel surveys; mark-recapture, broodstock, juvenile fish outmigration, and adult trapping for return migrants.  These data provide the foundation of estimates used to generate run size forecasts, status assessment, identification of hatchery strays, and growth analyses.  Examples of some of the large projects that FLHAP has been involved with include:

·         estimates of age composition for Chinook salmon returning to Oregon coastal basins, used in stock assessment models for the Pacific Salmon Treaty;


·         estimates of age composition for coastal chum salmon stocks and origin (hatchery or wild) information for Columbia River coho salmon as part of Oregon Plan monitoring needs;


·         estimates of age composition for various adult salmonids and juvenile steelhead outmigrants within the Hood River basin for Hood River Research;  


·         estimates of age composition and life history type of Chinook salmon as part of the Willamette Biological Opinion;


·         estimating the age composition of Chinook salmon caught in the ocean fishery, and whose basin of origin has been identified through DNA for Project CROOS (Collaborative Research on Oregon Ocean Salmon).


A more complete description of the project can be found here.  



Scales and field data are collected by district and research project personnel and sent to the FLHAP, which prepares the scales for analysis. Most scales are analyzed by visual interpretation. Scale analysts are trained and tested using collections of known origin and known age scales, usually from coded-wire tagged fish.  If measurements are required for purposes of back-calculating lengths or discriminant function analysis, we use an image analysis system to measure meristics and morphology.  Depending on the needs of the project that collected the scales, the FLHAP will return basic scale analysis results, statistical analyses or a short report.

When the requested work is completed on a scale collection, it is placed in the scale archive which is administered by the FLHAP.  The scale archive is the historical repository of scale collections from around the state of Oregon.

The FLHAP processes between 10,000 and 20,000 scales per year.  Samples from 2011 are from the largest number of fish to date, at an estimated 22,000 fish.  The project has typically been staffed by 2 full times employees:  one project leader and one EBA.  In the past, the project has swelled to a third, part time employee, hired on an as-needed basis.

Methods for scale collection, preparation and data management can be found here.




The FLHAP is in the process of conducting the following tasks:

·         Update and improve electronic data organization

o   Creation and use of standardized Access databases

o   Improve electronic file organization and accessibility

·         Update and improve organization and access to “reference” scale samples for various projects.

·         Update and improve sample storage in the scale archive

o   Physical scale samples

o   Electronic data 

·         Improve and disseminate protocols/procedures

·         Encourage more collaboration with age validation via CWT and PIT tags, whenever possible

·         Conduct power analyses to estimate the minimum number of scale samples needed for statistically-meaningful data

·         Prepare otoliths for microstructure analyses, including identification of thermal marks on hatchery-reared fish

·         Improve visualization and analytical capabilities of scale and otolith morphologies and meristics.





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