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 salmon migrated earlier than their hatchery‐reared counterparts but also over a protracted period. This study demonstrated that PIT tag technology can be used successfully to monitor migrations of wild and hatchery chinook salmon smolt stocks during their journey to the ocean.

Relating Size of Juveniles to Survival Within and Among Populations of Chinook Salmon

“…7). Each population has distinct migrational timing (Achord et al 1996), so the arrival timing versus length relationship exists on a per-population basis. Thus our second hypothesis is that larger fish within populations have relatively higher juvenile survival, at least partially, because they spend less time exposed to hazards such as predators.…”

“…1). These streams represent a broad spectrum in terms of habitat quality (Paulsen and Fisher 2001), physical features such as temperature regimes, and presence or absence of nonindigenous predators (Achord et al 1996(Achord et al , 2001) which may compete with or prey upon juvenile chinook (Levin et al 2002, Achord et al 2003. For convenience, we refer to the fish from each tagging site as a population.…”

“…We also limited our analysis to fish we tagged in the Salmon River Basin to ensure standardized methodology and to limit geographically based genetic variation (Mathews and Waples 1991). Details of the collection and tagging procedures are provided by Achord et al (1996Achord et al ( , 2001. Captured fish were brought to a mobile field station, anesthetized, the fork length of each fish was recorded, and a subset of fish was weighed, weather permitting.…”

In‐Channel Placement of Structure to Enhance Habitat Complexity and Connectivity for Stream‐Dwelling Salmonids

“…Passive integrated transponder (PIT) tags have been widely used to investigate timings (e.g. Achord et al 1996) and patterns of fish migration for decades (e.g. Flagg & Prentice 1988).…”

Post-Release Attributes and Survival of Hatchery and Natural Fall Chinook Salmon in the Snake River; 2000-2001 Annual Report.

“…In contrast, spring chinook salmon display a stream-type life history which is accompanied by rearing in tributaries for a year before initiating seaward migration in the spring as yearlings (Healey 1991). Yearling and subyearling chinook salmon migrations are generally temporally segregated, but some yearling spring chinook salmon also migrate during the summer (Achord et al 1996). Late migrating yearlings comprised 12-78% of the summer outmigration past Lower Granite Damthe upper-most dam on the lower Snake Riverfrom 1992 to 1997.…”