Since time immemorial, aboriginal people of the Confederated Tribes of the Warm Springs Reservation of Oregon (CTWSRO) have harvested fall Chinook salmon (Oncorhynchus tshawytscha) for subsistence, ceremonial, and medicinal purposes.  Not only is this species culturally significant, but it also has a high economic and recreational value to non-Indians.  The CTWSRO has co-management authority of fisheries resources in the Deschutes River with Oregon Department of Fish and Wildlife (ODFW).  Deschutes River fall Chinook are an indicator stock managed under the Pacific Salmon Treaty (PST) and is used to determine ocean harvest.  The CTWSRO has obligations to provide reliable escapement estimates to the United States Chinook Technical Committee, the body that implements the PST.  The ODFW has obligations to provide escapement estimates to the Columbia River Compact, which sets in-river harvest.  

Much of the data collection for fall Chinook in the Deschutes Basin has centered on providing escapement estimates of returning adults.  Aerial surveys for fall Chinook redds, in conjunction with tagging returning adults at Sherars Falls (river kilometer, Rkm, 70) and Pelton trap (Rkm 161), and carcass surveys are used to estimate abundance.  Aerial redd surveys have been conducted in index reaches and/or from the mouth to Pelton Re-regulating Dam (Rkm, 161) since 1977.  Prior to 1977, redd enumeration was conducted sporadically and sample areas were not consistent.  Efforts to validate redd counts in the Deschutes River took place in 2007  and 2009.  Juvenile fall Chinook were tagged with coded wire tags (CWT) from April through June 1978 to 1980 and again from late-April or May through June 2002 to 2009.  Adult Chinook with CWTs recovered in various fisheries were reported through Pacific States Marine Fisheries Commission Regional Mark Processing Center.  In 2011, we conducted a PIT tag feasibility study to determine how many out-migrant juvenile fall Chinook could be PIT tagged upstream of Sherars Falls.  Our efforts were successful in tagging 20,000 fish therefore efforts were continued through 2016.  In 2017, we propose to engage the services of statisticians to guide us in determining whether our objections can be met as all adults from the 2011 brood year have returned.  We also want them to assist in designing a study to determine detection probability at the array at the mouth of the Deschutes River, known as interrogator site DRM.  This will benefit the study into the future so that smolt to adult return ratios of this stock can be determined.

The limited data documenting juvenile fall Chinook ecology in the Deschutes River was collected as part of CWT studies.  Anticipated changes in the thermal regime, new information about genetic population structure of fall Chinook, and an upcoming opportunity to collect novel data on migration timing, smolt-to-adult ratios and possibly abundance estimates in the lower Deschutes River warrant further studies targeting the juvenile life history stage.  Another opportunity that has been recognized is performing genetic analysis of juvenile fall Chinook that have been PIT tagged and are detected as adult returns to the Deschutes River and comparing proportions of those that express the gene for coldwater tolerance in terms of survival.  This information will be used to support the management action of returning the thermal regime of the Deschutes River to the historic pattern.  

In 2016 - 2017, study objectives are to:
Passive Integrated Transponders (PIT) tag up to 25,000 juvenile fall Chinook in the Deschutes River;
Install antenna array at Sherars Falls
Collect data at the Deschutes River mouth and Sherars Falls PIT arrays;
Conduct aerial redd counts; and,
Conduct carcass surveys to recover PIT tags.