Gene M. Matthews

Use of Passive Integrated Transponder (PIT) Tags to Monitor Migration Timing of Snake River Chinook Salmon Smolts

Abstract Before 1989, there was little detailed knowledge of the migrational timing of wild smolts of Snake River spring and summer chinook salmon Oncorhynchus tshawytscha from individual streams. With the development of the passive integrated transponder (PIT) tag and methods for collecting and tagging parr, acquisition of information on migrational timing became feasible. We PIT-tagged wild chinook salmon parr in several streams in Idaho and Oregon each summer from 1988 through 1990. Each subsequent spring and summer, we detected surviving smolts on their migration through Lower Granite Dam. We also PIT-tagged hatchery-reared parr during fall or late winter and compared their migrations with those of wild fish. Migrational timing of wild smolts through Lower Granite Dam varied for fish from different streams and also differed from hatchery-reared fish. Generally, wild spring chinook salmon migrated later and over a more protracted period than their hatchery-reared counterparts. Wild summer chinook salmo...

Renibaeterium salmoninarum in Spring–Summer Chinook Salmon Smolts at Dams on the Columbia and Snake Rivers

Abstract We evaluated Renibaeterium salmoninarum infection in smolts of hatchery and wild spring-summer Chinook salmon Oncorhynchus tshawytscha sampled during most of the outmigration at Little Goose (1988) and Lower Granite dams (1988–1991) on the Snake River and at Priest Rapids and McNary dams on the Columbia River (1988–1990). We sampled 860–2,178 fish per dam each year. Homogenates of kidney–spleen tissue from all fish were tested for the presence of R. salmoninarum antigens by the enzyme-linked immunosorbent assay (ELISA), and homogenates from 10% of the fish were examined by the fluorescent antibody technique (FAT). Although only 1–11% of fish sampled at a given dam during any l year exhibited lesions characteristic of bacterial kidney disease, 86–100% of the fish tested positive for R. salmoninarum antigen by ELISA, whereas 4–17% of the fish tested positive by the FAT. During most years, a majority (68–87%) of fish testing positive by the ELISA had low R. salmoninarum antigen levels, but in 1989, ...

Diversion of Salmonid Smolts Tagged with Passive Integrated Transponders from an Untagged Population Passing through a Juvenile Collection System

Abstract We evaluated a system to divert salmonid smolts tagged with passive integrated transponders (PIT) from the general migrant population as they passed through a juvenile collection system at a hydroelectric dam on the Snake River. Our goal was to maximize the diversion of PIT-tagged fish while simultaneously minimizing the diversion of untagged fish. The slide-gate system that was tested diverted 81% of PIT-tagged fish detected. The number of untagged fish entering the diversion system with every PIT-tagged fish was proportional to fish abundance and averaged one untagged fish for every PIT-tagged fish. Measures of descaling, injury, and mortality for all fish in the diversion system were similar to those for fish that were not diverted. These results established our basic PIT-tag diversion system as a major tool for conducting research on Snake River anadromous salmonids.

Static Seawater Challenge Test to Measure Relative Stress Levels in Spring Chinook Salmon Smolts

Abstract A static seawater challenge test was successfully developed and used to establish a profile of the relative stress levels of spring chinook salmon smolts Oncorhynchus tshawytscha within the smolt collection and transport system at Lower Granite Dam on the Snake River. A major feature of the test was the development of water-to-water transfer techniques designed to assure minimal stress interference associated with sampling and transferring test fish from the freshwater sample sites to the seawater test chambers. The test was used to isolate stresses associated with movement of smolts through the system, with handling and marking procedures, and with holding spring chinook salmon smolts in the presence of predominately hatchery-reared steelhead Salmo gairdneri smolts. The test results clearly indicated a pattern of increasing stress levels as smolts moved through the system. The bypass system, the fish and debris separator complex, and transport by truck were areas where stress levels increased. D...

Homing in Sockeye and Chinook Salmon Transported around Part of Their Smolt Migration Route in the Columbia River

Abstract We evaluated homing efficiency of adult Pacific salmon Oncorhynchus spp. that had been transported as smolts around portions of their migration route in the Columbia River. We captured smolts of sockeye salmon O. nerka and spring chinook salmon O. tshawytscha at Priest Rapids and Wanapum dams and released marked control groups at the left bank of the Columbia River, just downstream from Priest Rapids Dam (river kilometer, rkm, 639 from the mouth of the river). In 1984–1986, we transported marked sockeye and chinook salmon smolts in trucks to the river edge downstream from Bonneville Dam (rkm 205). In 1987–1988, we compared truck transport of sockeye salmon with combined transport by truck to McNary Dam (rkm 467) and by barge from McNary Dam to the middle of the river downstream from Bonneville Dam. We compared ratios of transported to control Pacific salmon observed as adults at Bonneville Dam (2.55 for sockeye salmon, 2.43 for chinook salmon) and at Priest Rapids Dam (1.29 for sockeye salmon, 0....

Technical Notes: A Technique to Minimize the Adverse Effects Associated with Handling and Marking Salmonid Smolts

Abstract A system that allows anesthetization of juvenile salmonids before netting during a handling and marking operation is described. Our purpose for designing the system was to reduce or minimize any debilitating effects associated with these activities. When compared with smolts handled and marked in the traditional manner, use of the technique resulted in a significant reduction in the mortality of naturally migrating smolts of spring-summer chinook salmon Oncorhynchus tshawytscha during a posthandling and marking seawater challenge performance test. The treatment resulted in lower, but not significantly lower, plasma cortisol levels; however, sample sizes may have been too small for statistical verification. With a little ingenuity, the technique should be adaptable to most smolt handling or marking operations.

Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1994 Annual Report.

The goals of this study are to (1) characterize the outmigration timing of different wild stocks of spring/summer chinook salmon smolts at dams on the Snake and Columbia Rivers, (2) determine if consistent patterns are apparent, and (3) determine what environmental factors influence outmigration timing. The authors PIT tagged wild spring/summer chinook salmon parr in the Snake River Basin in 1993, and subsequently monitored these fish during their smolt migration through Lower Granite, Little Goose, Lower Monumental, and McNary Dams during spring, summer, and fall 1994. This report details their findings.