5/25/2016  |   10:30 - 10:45   |  302-303

WHY DO THE FISH MOVE? MULTIPLE SPATIAL SCALE PREDICTORS OF JUVENILE COHO SALMON WINTER MOVEMENT TIMING. Pacific salmon are highly mobile fish, relying on a diversity of habitats throughout life history transitions. However, movement also occurs seasonally and within life stages. This is especially true for juvenile coho salmon during the winter, an important rearing season prior to ocean outmigration. Multiple studies have documented varied winter-rearing strategies by coho salmon, including downstream movement. However, what affects these varied strategies are not well understood. To address this knowledge gap, juvenile coho salmon were tracked across four streams during the 2014 to 2015 winter season in the Russian River watershed, California using PIT technology. Coho salmon movement patterns were compared to landscape, environmental, and morphological variables, including catchment and riparian land use, geomorphology, temperature, prey availability, and fish morphology. Multiple predictors influence movement of juvenile coho salmon, but the scale of influence was variable. As more droughts are predicted and populations continue to decline, understanding the spatial and temporal scales at which an endangered coho population functions in a southern watershed is important to population recovery efforts across the coho salmon range.

Amelia Johnson (Primary Presenter/Author), Portland State University, alj7@pdx.edu;


Mariska Obedzinski ( Co-Presenter/Co-Author), California Sea Grant, mobedzinski@ucsd.edu;


Angela Strecker ( Co-Presenter/Co-Author), Portland State University, strecker@pdx.edu;


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5/25/2016  |   10:45 - 11:00   |  302-303

THE INTERACTING EFFECTS OF CLIMATE, DENSITY AND WATER WITHDRAWAL ON JUVENILE STEELHEAD SURVIVAL AND MIGRATION: INSIGHTS FROM AN 8-YEAR STUDY Individual behaviors of fish are tightly coupled to flow and temperature conditions in their freshwater environment. Understanding how a changing climate will affect river conditions for juvenile salmon must be considered in the context of multiple coincident stressors. We have been studying how local abiotic conditions and population density influence performance of juvenile steelhead (Oncorhynchus mykiss) across an entire watershed characterized by variable levels of anthropogenic impact. We tagged >10,000 individuals and quantified spatially explicit growth, survival, and migratory decisions. Temperatures in parts of the watershed exceeded the thermal tolerance for juvenile steelhead in late summer, with prolonged periods during the warmest years. Bioenergetic modeling suggests a size-dependent metabolic constraint on individual growth rates. In turn, this energetic bottleneck increases mortality of relatively large individuals. The probability of survival had a significant influence on the likelihood of outmigration for overyearling individuals. Our results suggest that the basis for migratory decisions can be highly variable throughout a watershed, and demonstrate how an individual-based and spatially explicit approach is desirable for understanding the causes and consequences of life history variability.

Brian Kennedy (Primary Presenter/Author), University of Idaho, Kennedy@uidaho.edu;


Natasha Wingerter ( Co-Presenter/Co-Author), University of Idaho, wing4979@vandals.uidaho.edu;


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5/25/2016  |   11:00 - 11:15   |  302-303

SUMMERTIME MOVEMENT AND MICROHABITAT USE BY BROOK TROUT IN A SMALL MICHIGAN STREAM Protection and improvement of trout habitat requires an understanding of a stream’s physical characteristics as well as the seasonal habitat requirements, movement patterns, and habitat use of the targeted trout species. Using radio telemetry, we tracked 12 brook trout (Salvelinus fontinalis) in Cedar Creek, MI during summer, 2015 to determine patterns of movement, thermoregulatory behavior and microhabitat use. Although water temperatures often exceeded ideal water temperature for brook trout (16°C), brook trout body temperatures were generally slightly cooler than ambient water temperatures. However body temperatures were still above the ideal range for brook trout for most of the summer. Additionally, all brook trout tagged in an upstream section of the study area moved to a cooler downstream reach as temperatures increased. Observed summer movement patterns and microhabitat use by brook trout in Cedar Creek may be related to the condition of the surrounding riparian zone or the availability of thermal refugia.

Justin Wegner (Primary Presenter/Author), Annis Water Resources Institute, Grand Valley State University, wegnerju@mail.gvsu.edu;


Graeme Zaparzynski ( Co-Presenter/Co-Author), Annis Water Resources Institute, Grand Valley State University, zaparzyg@mail.gvsu.edu ;


Mark Luttenton ( Co-Presenter/Co-Author), Annis Water Resources Institute, Grand Valley State University, luttentm@gvsu.edu;


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5/25/2016  |   11:15 - 11:30   |  302-303

SEASONAL VARIATION IN FORAGING AND COMPETITIVE BEHAVIORS IN CUTTHROAT TROUT The looming threat of climate change makes it more important than ever that we understand how the winter affects fish ecology. But there are many challenges that confront ecologists hoping to study fish throughout the year, and this has resulted in few studies of fish ecology in non-summer months, particularly in the winter. The past few years have seen an increase in interest in the winter ecology of fish, but most studies are still limited to looking at fish survival and changes to body condition. The goal of this study was to determine how the foraging and competitive interactions of coastal cutthroat trout (Oncorhynchus clarkii) change throughout the course of the year. I will present results from infrared underwater cameras that were used to capture trout behavior and will discuss how differences in time of day, water temperature, flow, and food availability predict changes in cutthroat behavior and place these results in the broader context of climate change.

Elizabeth Perkin (Primary Presenter/Author), Willamette University, lizperkin@gmail.com;


John Richardson ( Co-Presenter/Co-Author), University of British Columbia, John.Richardson@ubc.ca;


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5/25/2016  |   11:30 - 11:45   |  302-303

VARIATION IN TEMPERATURE-DEPENDENT GROWTH RATES IN JUVENILE CHINOOK SALMON: THE NEED FOR POPULATION-SPECIFIC BIOENERGETICS Growth of juvenile salmonids is a critical variable affecting survival and recruitment to successive life history stages, essentially affecting the strength of subsequent cohorts. Consumption and temperature are key variables affecting growth. Temperature dictates the metabolic efficiency of prey conversion to production, and thus primarily affects growth. However, temperature optima and thresholds are variable for Pacific salmon populations. Yet many researchers using bioenergetic approaches to understand growth use temperature-dependent equations and coefficients for Chinook Salmon from the published literature that are not very relevant to their study population. To address this problem we are using several lines of evidence to better understand relationships between temperature and key bioenergetic functions. We focus this effort on juvenile Chinook Salmon used in the San Joaquin River Restoration Program, which seeks to restore the southern-most run in North America. Our approach includes growth simulation using coefficients from different literature sources, simulations with inSTREAM and bioenergetics models, and two hatchery data sets. The main objectives are to generate specific bioenergetics algorithms and encourage a broader use of population-specific relationships of temperature and growth rate.

Steve Blumenshine (Primary Presenter/Author), Fresno State University, sblumens@csufresno.edu;


Taylor Spaulding ( Co-Presenter/Co-Author), Fresno State University, tspaulding@mail.fresnostate.edu;


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5/25/2016  |   11:45 - 12:00   |  302-303

EFFECTS OF LOW STREAM FLOW ON JUVENILE SALMONIDS IN TRIBUTARIES OF THE RUSSIAN RIVER, CALIFORNIA Low stream flow is thought to be a limiting factor for survival of endangered coho salmon and threatened steelhead populations in the Russian River; however, quantifying the impacts of low flow is difficult. As in many small California coastal streams, summer surface flows in Russian River tributaries drop to levels that are so low they are difficult to accurately measure and in many cases streams become intermittent or completely dry, especially during drought years. In order to document the wetted habitat conditions that rearing juveniles experience during the driest time of the year, spatial data was collected in late summer to document where the streams were wet, intermittent or dry. Wetted habitat data was then related to redd location information collected the previous winter and juvenile snorkeling count data collected earlier in the summer season. Results from three years of data collection indicate that the majority of adults spawned in stream reaches that went dry the following summer, and that in most cases juveniles were also concentrated in stream reaches that went dry later in the season.

Mariska Obedzinski (Primary Presenter/Author), California Sea Grant, mobedzinski@ucsd.edu;


Andrew Bartshire ( Co-Presenter/Co-Author), California Sea Grant, abartshire@ucsd.edu;


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