Life History Variability, Habitat Use, and Migratory Behavior of Coastal Cutthroat Trout in the Salmon River, Oregon Report Number: OPSW-ODFW-2012-10

Identification Information

Citation

Originator: Stein, S., T. Cornwell and K. Jones

Publish Date: February 2012

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Cedric Cooney

Job Position: Natural Resources Data and Systems Manager

Telephone: 503-947-6094

E-Mail Address: cedric.x.cooney@odfw.oregon.gov

Description

Abstract: Coast basins in Oregon support resident and anadromous cutthroat trout (Oncorhynchus clarki clarki). Cutthroat trout isolated above barriers are stream resident, but those with access to river, estuary, and marine environments may express a variety of life history and migratory patterns. Past studies (e.g. Giger 1972, Sumner 1972, Tipping 1981) indicated that estuaries serve primarily as a migratory corridor or short-term rearing environment. However, recent advances in marking and tracking technology have permitted researchers to gain a better understanding of the complex migratory and habitat use patterns of cutthroat. Krentz (2007) conducted studies in Salmon River on the central Oregon coast to explore migratory patterns of cutthroat and examine the role of the estuary as a rearing environment. Coastal cutthroat trout reared for extended periods of time throughout the available channel habitats in Salmon River estuary (Krentz 2007) during spring, summer, and fall. The estuarine resident population appeared to represent a significant portion of the migratory individuals, and included all older age classes. Estuary growth was similar to that of their ocean migrant counterparts, and survival in the estuary was high. Because cutthroat were collected and marked primarily within the estuary (Krentz 2007), it is unclear what portion of the migrant population reared in the estuary relative to the watershed or ocean, or whether the tagged group was representative of the migratory populations. The current study was designed to track a representative sample of the downstream migrant population, and assess the relative success (survival) of the estuary and ocean migrants. Similar studies in the Columbia River documented directed and rapid migration through the estuary (Zydlewski et al. 2008, Hering et al. 2009). With rare exception, cutthroat trout were not observed to rear in the estuary. In addition, many fish disappeared before reaching the ocean and few of the ocean migrants returned to the natal tributary. In this study we replicated the study design used in the Columbia River studies to further comparisons of estuary migration and rearing strategies between the two estuaries. The primary objective of our work in the Salmon River was to increase understanding of coastal cutthroat trout biology and the relationship between stream-resident and migratory, or “sea-run” cutthroat. Here we use the term “sea-run” to indicate migration into the tidally-inundated, or estuarine portions of the Salmon River watershed or to the ocean. Study objectives were to: 1.Estimate the distribution and abundance of coastal cutthroat trout in the Salmon River watershed 2.Quantify the proportions of the cutthroat populations that are migratory, identify which individuals migrate and describe the timing of migration 3.Describe estuary habitats used by sea-run migrants and characterize behavior within the Salmon River estuary 4.Estimate growth rate of stream and estuary resident cutthroat 5.Estimate estuary and ocean survival of sea-run individuals and document return to estuary and lower river. 6.Compare migratory behavior in Salmon River to that observed in the lower Columbia River

Purpose:

Time Period of Content:

Geographic Extent: Salmon River

Status: Final

Use Constraints:

Format: PDF File

Data Quality Information

Lineage-Source:

Data Information

No data information was supplied.

Entity and Attribute Information

Attributes Description:

Is a physical copy maintained for reference at Headquarters? Yes