Brian R. Fransen

Response of Juvenile Coho Salmon and Steelhead to Placement of Large Woody Debris in a Coastal Washington Stream

Abstract Many fish habitats have been altered in Pacific Northwest streams and rivers over the past century by a variety of land use practices, including forestry, urbanization, agriculture, and channelization. There are research and management needs for evaluation of the effectiveness of rehabilitation projects intended to enhance stream fish habitat recovery. The response of populations of juvenile coho salmon Oncorhynchus kisutch and steelhead O. mykiss to addition of large woody debris (LWD) was tested in North Fork Porter Creek (NFPC), a small coastal tributary of the Chehalis River, Washington. The NFPC was divided into three 500-m study sections; two sections were altered with two approaches (engineered and loggers choice) to adding LWD, and the third was kept as a reference site. Immediately after LWD addition, the abundance of LWD pieces was 7.9 times greater than the pretreatment level in the engineered site and 2.7 times greater in the loggers choice site; abundance was unchanged in the refer...

Preliminary Evaluation of the Use of Nitrogen Stable Isotope Ratios to Establish Escapement Levels for Pacific Salmon

Abstract Research over the last decade has established the ecological significance of the nutrients and organic matter deposited by Pacific salmon in the freshwater habitats where they spawn. A large proportion of the nitrogen in plants and animals in streams where salmon are abundant may be derived from spawning fish, and juvenile salmonids exhibit higher growth rates at locations where carcasses are available. Currently, no method is available to establish salmon escapement goals that meet the nutritional needs of streams. We examined the relationship between the abundance of spawning coho salmon (Oncorhynchus kisutch) and the nitrogen stable isotope ratio of coho salmon parr to determine whether a saturation level for salmon-derived nitrogen could be identified. Coho parr were collected from 26 sites in western Washington in late winter. The isotope ratio in the coho parr was related to the abundance of salmon spawning at that site the previous autumn. The amount of carcass-derived nitrogen increased w...

Transfer of Nutrients from Spawning Salmon to Riparian Vegetation in Western Washington

The extent to which nutrients from Pacific salmon are transported to riparian areas may be influenced by differences in spawning behavior among species. Chum salmon Oncorhynchus keta, pink salmon O. gorbuscha, and sockeye salmon O. nerka typically spawn in dense aggre- gations, while species like steelhead O. mykiss and coho salmon O. kisutch spawn at lower densities. The contribution of nutrients to riparian vegetation was compared at two watersheds in western Washington, Griffin Creek (used by coho salmon) and Kennedy Creek (used by chum salmon). Salmonberry Rubus spectabilis foliage was collected at the channel edge above and below barriers to spawning salmon and at 20, 50, and 100 m upslope from the stream and analyzed for nitrogen stable isotope ratio ( d 15N, an indicator of salmon-derived nitrogen), total nitrogen (N), and phos- phorus (P) content. Cover, plant density, and the species richness of shrub and understory vegetation were compared between sites with and without salmon. The d15N values in salmonberry leaves were higher at sites with salmon than at corresponding distances from the channel at sites without salmon at Kennedy Creek but not Griffin Creek. Salmonberry foliage adjacent to salmon spawning reaches possessed significantly higher levels of total N and P in both watersheds. Nitrogen content was positively associated with d15N values at the Kennedy Creek sites but not at the Griffin Creek sites. At Kennedy Creek, shrub species diversity and understory plant density and species diversity were higher at sites with salmon than at sites without salmon. These results suggest that areas bordering streams utilized by high-density-spawning species like chum salmon receive a substantial nutrient contribution from the fish and that this subsidy influences the vegetation. We did not see clear evidence for a similar nutrient contribution from coho salmon. Anadromous salmonids Oncorhynchusspp. play a key role in the nutrient and trophic dynamics of aquatic ecosystems in watersheds tributary to the northern Pacific Ocean (Kline et al. 1990, 1994; Bilby et al. 1996; Johnston et al. 1997). More than 95% of the body mass of Pacific salmon is accu- mulated in the marine environment (Groot and Margolis 1991). This material is transported to the streams, rivers, and lakes where the salmon spawn and die. The importance of this nutrient and or- ganic matter subsidy has long been recognized for lakes supporting sockeye salmon O. nerka (Juday et al. 1932). More recent research has demonstrat- ed that the eggs and carcasses deposited in streams

Effects of Immersion in Water on Deterioration of Wood from Five Species of Trees Used for Habitat Enhancement Projects

Abstract Logs of standard dimensions from five species of trees were submerged in a stream to evaluate changes in strength and decomposition over a period of 5 years. Changes in structural properties occurred only for wood near the outer surface of the logs. Nearly all bark was removed from the logs within 12 months. Diameter loss for the five species ranged from 10.6 mm (western hemlock Tsuga heterophylla) to 21.8 mm (bigleaf maple Acer macrophyllum) after 5 years. Decreases in the density of surface wood for the five species ranged from 23% (red alder Alnus rubra) to 31% (western hemlock). Modulus of rupture, modulus of elasticity, and wood density did not change for wood more than 12 mm from the log surface for any of the species. Bigleaf maple exhibited the highest resistance to rupture, and western redcedar Thuja plicata exhibited the lowest. Western redcedar was also the most easily flexed. Microbial activity on the surface of the logs was highest at the start of the experiment and decreased rapidly...

A Logistic Regression Model for Predicting the Upstream Extent of Fish Occurrence Based on Geographical Information Systems Data

Abstract Regulations governing human activities in streams and riparian zones frequently differ depending on whether or not a stream reach supports fish. Fish presence or absence is usually determined by sampling or by assuming the presence of fish if the stream exhibits certain physical characteristics. Field surveys of fish occurrence in streams are time consuming and expensive. Inference of fish presence from simple thresholds of physical attributes, such as gradient or channel width alone, is inaccurate. We attempted to improve the accuracy and efficiency of this determination by developing a geographical information systems (GIS)-based predictive model. A 10-m digital elevation model incorporated field data on fish distribution from 517 streams in western Washington State and GIS-derived representations of the physical characteristics of stream networks. A model predicting the upstream extent of fish occurrence was derived using logistic regression models coupled with a heuristic “stopping rule.” Can...

Status and Plight of the Searun Cutthroat Trout

The Endangered Species Committee of the American Fisheries Society recently identified all Washington, Oregon, and California populations of searun cutthroat trout, the anadromous form of the coastal cutthroat trout, Oncorhynchus clarki clarki, as being at some level of risk of extinction (Nehlsen et al., 1991). Here we focus on these at risk populations, listing reasons for their decline as set forth by the AFS Committee. We then review the life history, ecology, and genetic population structure of the subspecies, and from this identify gaps in our knowledge that will have to be filled if these populations are to be preserved.

Change in the Upper Extent of Fish Distribution in Eastern Washington Streams between 2001 and 2002

Abstract The upper extent of fish distribution in streams has received increasing attention in recent years because fish-bearing streams in the Pacific Northwest receive greater protection from timber harvest than do non-fish-bearing waters. Significant amounts of time and funding have been spent surveying streams for the upper extent of fish distribution and, more recently, in developing models that predict where fish use ends in streams. The reliability of each approach rests in part on the assumption that the upper extent of fish distribution can be accurately determined by a single survey and that fish distribution boundaries (FDBs) do not shift appreciably through time. To examine changes in the upper extent of fish distribution, streams were surveyed throughout 10 forested watersheds in eastern Washington in the summers of 2001 and 2002. In 2002, 308 FDBs were resurveyed. Resurveys resulted in the establishment of 172 terminal boundaries (occurring mid-channel or at the confluence of two non-fish-be...