GRANT NUMBER: NA66FD0105          NMFS NUMBER:   95-NWR-028

REPORT TITLE: Evaluation of Electronic Detection for Coded-Wire Tags in Salmon from Commercial, Sport and Hatchery Rack Sampling Programs

AUTHOR:  Blankenship, Lee; Washington Department of Fish and Wildlife

PUBLISH DATE: March 1997

AVAILABLE FROM: National Marine Fisheries Service, Northwest Regional Office, 7600 Sand Point Way, NE, Seattle, WA 98115.  PHONE: (206) 526-6115

ABSTRACT

Mass marking adipose fins of hatchery coho salmon (Oncorhynchus kisutch) has been proposed as a tool to allow selective harvest fish while reducing exploitation of unmarked wild stocks. The adipose fin mark has historically been used as an indicator for the presence of an internal coded-wire tag (CWT). To maintain the viability of the CWT system as a management tool with mass marking adipose fins, the Pacific Salmon Commission (PSC) recommended that electronic detection be used to identify fish with CWTs. This project was designed to test and determine the reliability, feasibility, and staffing requirements of sampling for CWTs with electronic detection. Two types of electronic detectors were tested: a hand-held unit (wand) and a stationary unit containing a fish passage tube (R-8 tube). The wands and R-8 tube detectors reliably detected CWT's in coho salmon at rates at least as good as believed possible by visual detection.  Although feasible, electronic detection requires a significant increase in sampling time and effort when compared to the visual method.  Improvements in design by the manufacturer of the electronic detection equipment are expected to increase its reliability and feasibility.