Oregon Department Of Fish And Wildlife Research Articles

Implications of Metrics and Methodology for Juvenile Salmonid Monitoring in Western Oregon Streams

We attempted to determine whether electrofishing removal estimates or single-pass snorkeling was a more reliable method for Oregon Department of Fish and Wildlife (ODFW) monitoring of juvenile coho salmon (Oncorhynchus kisutch) and steelhead (O. mykiss) abundance and occupancy trends. Based on 1997 to 2000 data, we assumed abundance estimates from the method that tracked more closely with parental abundance would better approximate true juvenile abundance. Parental abundance from spawning ground surveys and juvenile abundance metrics unique to each method were estimated from 2000 to 2004 and 2007 to 2008. Parental abundance did not explain the variation in juvenile abundance from either method (r2 < 0.22), invalidating our assumption, but results had relevance for snorkel surveys used in ODFW monitoring. For both species, correlations between density (fish m2 -1) and abundance (quantity, based on fish km-1) estimates from snorkeling were weak (r < 0.379), but correlations between abundance estimates from both methods were strong (r > 0.846), implying abundance was more appropriate than density for ODFW monitoring. Neither method could sample all habitats, and annually variable proportions of coho salmon (15 to 47%) and steelhead (0 to 24%) abundance estimates obtained by electrofishing were in pools too shallow to meet the ODFW depth criterion for snorkeling. This resulted in lowering the criterion to ≥ 20 cm in 2010. The lower criterion, relative to original, has not shown differences in trends, but 30% more pools have been sampled, resulting in 23% higher abundance estimates with 10% proportionately smaller confidence intervals. These changes improved ODFW monitoring and related management decisions.

Observations of Kit Foxes in Southeastern Oregon

The kit fox (Vulpes macrotis) or V. velox macrotis (Dragoo et al. 1990) is found in desert and shrub steppe ecosystems throughout much of the southwestern United States and northwestern Mexico (Samuel and Nelson 1982). The species reaches the northern extent of its range in southeastern Oregon and southwestern Idaho. Vulpes v. macrotis is restricted to southeastern Harney and southern Malheur counties in Oregon (Benedict and Forbes 1979; Verts and Carraway 1984; Marshall 1988), with the exception of one isolated record from southern Klamath County (Laughlin and Cooper 1973). Early European settlers considered V. v. macrotis to be rare in Oregon (Marshall 1988). However, numbers apparently were reduced further from the 1940's throughout the 1970's with widespread use of poisons for coyote (Canis latrans) control (Olterman and Verts 1972; Kindschy 1983). Concern for the status of V. v. macrotis prompted the Oregon Department of Fish and Wildlife (ODFW) to list it as a threatened species in the state in 1975 (Durbin 1975). The few observations that have been reported in the last decade have been unconfirmed sightings by the public, with the exception of a highly visible family of 6-8 foxes that denned alongside U.S. Highway 95 near Burns Junction until 1985 (M. Eckstein, Burns Junction, Oregon, pers. comm.). The status of V. v. macrotis in Oregon in the past few years is uncertain. There has been speculation that few or no individuals remain in the state (Marshall 1988). Despite continued concern for V. v. macrotis in Oregon, no data beyond incidental sightings have been collected. My objectives were to determine if this species still occurred in Oregon and, if so, to document locations. This information was required by ODFW to justify continued listing of V. v. macrotis as a threatened species, and it was a first step toward evaluating potential recovery or management needs of the species.