OREGON STATE UNIVERSITY

Fisheries

The Effects of Stream Adjacent Logging on Downstream Populations of Coastal Cutthroat Trout
Bateman, D.S., R.E. Gresswell, A.M. Berger, D.P. Hockman-Wert, D.W. Leer
Apr-18-2013

Here we evaluate the response of a headwater fish community to forest management using a before, after, control, impact (BACI) study design. Annual fish abundance and biomass estimates are from a census of pool and cascade habitat units over the fish-bearing portion of both the reference and treatment catchments. Movement, survival, and growth were estimated from the monitoring and recapture of salmonids marked with passive integrated transponder (PIT) tags. Sampling consisted of an annual electrofishing and marking event during the low-flow period (2001-2011), and beginning in the winter of 2003, there were three annual mobile antenna PIT-tag survey events in December, March, and June. Additionally, continuously operating swim-through antennas were located at the downstream end of each stream segment. The study calibration phase occurred 2001-05. Treatment-1 (2006-2008) consisted of stream adjacent logging without retention of standing tree buffers with harvest units occurring in channels upstream from channel sections inhabited by fish. During Treatment-2 (2009-2011), there was stream adjacent logging with standard buffers as prescribed by current forest practice regulations. Analysis occurred at two spatial scales, tributaries only and catchments. Overall, very few detectable changes in habitat or biologic parameters were observed in conjunction with either treatment.

DISCIPLINE: Fisheries    STUDY: Hinkle Creek    TYPE: Presentations    TAGS: Fish, coastal cutthroat trout, logging, Oregon Forest Practices Rules, Habitat response
Relationships Between Stream Discharge and Cutthroat Trout Abundance at Multiple Scales in Managed Headwater Basins of Western Oregon
Owens, H.L.
Jun-17-2013

Relationships between resident cutthroat trout (Oncorhynchus clarkii clarkii) and six hydrologic indices were investigated using correlation analysis in two experimental headwater catchments in the foothills of the Cascade Mountains of western Oregon. This investigation was to determine if characteristics of discharge explained inter-annual variability in trout abundance. Eight years of continuous discharge and annual abundance data collected from two contiguous watersheds from the Hinkle Creek Paired Watershed Study were used for this study. Density-discharge relationships were identified separately in the watershed actively managed for timber harvest and in the control watershed. Correlation was determined at multiple stream segments and at the watershed scale to assess the roles of spatial scale and network location on the detectability of density-discharge relationships. A method for improving the spatial coupling of density and discharge measurements within the stream network was also investigated. No correlations (r ≤ ǀ0.50ǀ) between hydrologic indices and age-1+ trout density in either watershed were found. Two hydrologic indices were related to the density of age-0 trout: maximum annual discharge (r = 0.780) in the control watershed and Q90 summer discharge (r = 0.697) in the treated watershed. The correlation between the density of age-0 trout and each of these two indices were similar across individual stream segments, but variability in the magnitude of the...

DISCIPLINE: Fisheries    STUDY: Hinkle Creek    TYPE: Theses    TAGS: Cutthroat Trout, Variability, trout abundance, Density-discharge relationships
Factors Influencing Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) Seasonal Survival Rates: a Spatially Continuous Approach within Stream Network
Berger, A.M., R.E. Gresswell
Apr-10-2009

Mark–recapture methods were used to examine watershed-scale survival of coastal cutthroat trout (Oncorhynchus clarkii clarkii) from two headwater stream networks. A total of 1725 individuals (‡100 mm, fork length) were individually marked and monitored seasonally over a 3-year period. Differences in survival were compared among spatial (stream segment, subwatershed, and watershed) and temporal (season and year) analytical scales, and the effects of abiotic (discharge, temperature, and cover) and biotic (length, growth, condition, density, movement, and relative fish abundance) factors were evaluated. Seasonal survival was consistently lowest and least variable (years combined) during autumn (16 September – 15 December), and evidence suggested that survival was negatively associated with periods of low stream discharge. In addition, relatively low (–) and high (+) water temperatures, fish length (–), and boulder cover (+) were weakly associated with survival. Seasonal abiotic conditions affected the adult cutthroat trout population in these watersheds, and low-discharge periods (e.g., autumn) were annual survival bottlenecks. Results emphasize the importance of watershed-scale processes to the understanding of population-level survival.

DISCIPLINE: Fisheries    STUDY: Hinkle Creek    TYPE: Journal Articles    TAGS: Mark–recapture, abiotic factors, biotic factors, water temperatures, boulder cover
Passive Integrated Transponder Tag Retention Rates in Headwater Populations of Coastal Cutthroat Trout
Bateman, D.S., R.E. Gresswell, A.M. Berger
Jan-08-2011

Passive integrated transponder (PIT) tags have desirable qualities (e.g., unique identification, indefinite tag life, and capacity for remote detection) that make them useful for evaluating survival, growth, and movement of fish, but low tag retention rates can confound data interpretation. Although the effects of PIT tags on short-term growth and survival have been minimal and tag retention rates in laboratory and field studies using only juvenile individuals have been high, tag retention rates for fish at different ontological stages (including reproductively active males and females) remain unknown. We evaluated tag retention rates in wild populations of coastal cutthroat trout Oncorhynchus clarkii clarkii in three catchments of western Oregon using a double-marking approach (i.e., the adipose fin was removed from all fish that were PIT-tagged). Tags were inserted into the body cavities of fish 100 mm or more in length (fork length; range¼100–250 mm). In the study catchments, this size range includes both juvenile and mature fish. Tag retention rates were approximately 25% lower than those reported by previous studies of juvenile salmonids alone. A number of PIT tags were recovered in redds, indicating that mature individuals eject tags during spawning. Although some coastal cutthroat trout retained PIT tags for up to 4 years, others expelled them repeatedly and were implanted with a minimum of three different PIT tags during the same period.

DISCIPLINE: Fisheries    STUDY: Hinkle Creek    TYPE: Journal Articles    TAGS: Passive integrated transponder (PIT) tags, retention rates, double-mark, juvenile salmonids
Transferability of Models to Predict Selection of Cover by Coastal Cutthroat Trout in Small Streams in Western Oregon, USA
Andersen, H.V.
Nov-07-2008

We assessed use and selection of cover by coastal cutthroat trout (Oncorhynchus clarkia clarkii) in six headwater streams in three watersheds in western Oregon, USA during the summer low flow period from 1 August and September 30, 2007. We tagged 1037 coastal cutthroat trout (>100 mm) with passive integrated transponder (PIT) tags across all streams. Selection of cover was analyzed by comparing characteristics of locations used for concealment by relocated fish relative to characteristics of randomly available habitat that could be used for concealment. We measured habitat characteristics for 190 relocated individual fish using cover and 797 randomly points potentially available as cover. Of the latter points, only 235 of 797 were potential cover, based on characteristics of cover actually used by fish. Coastal cutthroat trout used substrate as cover (78%) more often than all other cover types combined (22%). Availability of different cover types was variable, but overall substrate made up 92% of available cover and the remaining 8% represented all other cover types combined. Habitat characteristics measured for both used and available cover included depth at fish location (cm), surface area of cover (m2), proximity to depth of 20 cm for fish located in < 20 cm in depth, b-axis (mm) for substrate >2 mm, and distance under substrate. Each of these habitat characteristics was different for used and available cover.

DISCIPLINE: Fisheries    STUDY: Alsea, Hinkle Creek, Trask    TYPE: Theses    TAGS: coastal cutthroat trout, cover, substrate, habitat selection, Headwater streams, PIT tags, transferability
Experimental Analysis of Intra- and Interspecific Competitive Interactions between Cutthroat Trout and Sculpins in Small Streams
Ramirez, B.S.
Dec-02-2011

In the Pacific Northwest ecoregion of North America, sculpins represent a major constituent of freshwater assemblages in coastal rivers. Little is known of their interactions with co-occurring species, such as widely studied salmon and trout (salmonines). In this study, I evaluated inter- and intraspecific interactions involving cottids (Cottus sp.) and coastal cutthroat trout (Oncorhynchus clarkii clarkii). I used a response surface experimental design to independently evaluate effects of cutthroat trout and sculpin biomass on growth and behavior. There was evidence of both intra- and interspecific interactions between cutthroat trout and sculpins, but the interactions were asymmetrical with biomass of cutthroat trout driving both intra- and interspecific interactions, whereas sculpins had little influence overall. Cutthroat trout biomass was positively related to conspecific aggressive interactions and negatively related to growth. Sculpin exhibited increased use of cover during the day in response to greater biomass of cutthroat trout, but not sculpin biomass. Nocturnal use of cover by sculpins was unaffected by biomass of either species.  This experiment provides insights into the species interactions and the mechanisms that may allow sculpins and salmonines to coexist in nature. As cutthroat trout appear to be superior competitors, coexistence between sculpins and cutthroat trout may depend on some form of refuge.

DISCIPLINE: Fisheries    STUDY: Alsea, Hinkle Creek, Trask    TYPE: Theses    TAGS: sculpins, intraspecific interactions, cottus, Oncorhynchus, coastal cutthroat trout, biomass, Oregon, competition
Seasonal Variability in Diet and Consumption by Cottid and Salmonid Fishes in Headwater Streams in Western Oregon, USA
Raggon, M.F.
May-27-2010

Coastal cutthroat trout (Oncorhynchus clarkii clarkii) and cottids (Cottus spp) commonly co-occur in headwater streams in western Oregon. Little is known about the comparative trophic ecology of these species or how they respond to seasonal scarcity of resources. In this study I evaluated the seasonal variability in diets and consumption as it related to food limitation for coastal cutthroat trout and cottids. Over 340 individual diets were quantified from seasonal samples collected in May, July and September of 2008. Diet overlap was relatively low among seasons and species. Coastal cutthroat trout exhibited a more diverse diet in terms of taxonomic richness of prey and consumed both aquatic and terrestrially-derived prey, whereas cottids appeared to specialize on aquatic prey. Based on diet composition and amount consumed, all species appeared to be increasingly food limited from July to September, relative to May. However when diet composition was integrated with a bioenergetic model, coastal cutthroat trout were found to be substantially more food limited than cottids. Differences in the cost of activity between these species may explain this result. Activity costs may be higher for trout, which reside in the water column and rely on active swimming, versus cottids, which lack a swim bladder and are more benthic oriented. Results of this work suggest that cottids are dietary specialists, feeding almost exclusively on benthic prey.

DISCIPLINE: Fisheries    STUDY: Trask    TYPE: Theses    TAGS: coastal cutthroat trout, cottus, diet composition, bioenergetic models, food limitation, seasonal variation, ecology, Oregon
Fish Population Response to Harvesting with Contemporary Forest Practice Regulations: The Alsea Watershed Study Revisited
Bateman D., R. Gresswell, D. Hockman-Wert, D. Leer, and J. Light
Apr-18-2013

Coastal cutthroat trout Oncorhynchus clarkii clarkii are the most widely distributed native salmonid in the forested watersheds of western Oregon. The initial Alsea Watershed Study demonstrated negative impacts on the abundance of cutthroat trout due to logging practices of the day. Here we report on abundance, size, growth, and condition of coastal cutthroat trout before and after logging under the current forest management practice regulations using a before, after, control, impact (BACI) study design with Flynn Creek and Needle Branch as the control and impact streams respectively. Relative abundance estimates are from a census of pool habitats using single-pass electrofishing and relative growth is from the recapture of individuals implanted with passive integrated transponder tags. A significant increase in age 1+ cutthroat trout biomass and abundance was observed post-harvest in Needle Branch relative to Flynn Creek (p=0.04 and 0.01 respectively). There was also a significant shift in the spatial distribution of cutthroat biomass in Needle Branch (p=0.04) in an upstream direction post-treatment suggesting that increases in cutthroat trout were spatially linked to the location of the harvest unit. There was no evidence for a treatment effect on mean fork length or the 90th percentile of fork length for age 1+ cutthroat trout (p=0.32 and 0.24 respectively). This result was supported by an absence of evidence for a treatment effect on relative growth rate.

DISCIPLINE: Fisheries    STUDY: Alsea    TYPE: Presentations    TAGS: Cutthroat Trout, single-pass electrofishing, biomass, habitat
The Importance of Location: Responsiveness of Stream-living Fish Populations
Penaluna B., S. Railsback, J. Dunham, S. Johnson, A. Skaugset, and R. Bilby
Apr-18-2013

The evolution of concepts in stream ecology has resulted in a collective recognition that location within a landscape matters to aquatic biota. Although it is known that location-related conditions have implications for aquatic biota, the contribution of location that most greatly influences a population has yet to be understood. Stream-living fish populations in headwater stream locations are affected by a juxtaposition of influences between more dynamic environmental regimes (i.e., flow, temperature, turbidity) and relatively fixed site-specific physical characteristics of streams also referred to as the physical ‘habitat template’ (e.g., channel geomorphology, instream habitat). Simulation experiments using the inSTREAM individual-based coastal cutthroat trout (Oncorhynchus clarkii clarkii) population model explored the role of environmental regimes and a habitat template for four headwater streams in the Trask River Watershed. We paired the suite of historic environmental regimes (i.e., flow, temperature, turbidity) from each site with the habitat template from each site (i.e., channel shape, velocity shelter availability, spawn gravel availability, distance to hiding refuge) using a full factorial design resulting in 16 different scenarios for both summer and winter over 4 years. We present evidence demonstrating that the role of the habitat template predetermines population dynamics by setting hierarchical boundaries to alternative environmental regimes.

DISCIPLINE: Fisheries    STUDY:    TYPE: Presentations    TAGS:
Persistence of Spatial Distribution Patterns of Coastal Cutthroat Trout in a Cascade Mountain Stream
Novick, M. S.
Dec-02-2005

Previous research in South Fork Hinkle Creek suggested that coastal cutthroat trout exhibit an aggregated spatial pattern across multiple spatial scales. To evaluate the persistence of the observed abundance patterns and identify factors that affect those patterns, half-duplex passive integrated transponders (PIT-tags) were implanted in 320 coastal cutthroat trout (> 100 mm, about age 1-plus fish) within our study sections, and in an additional 370 fish throughout the watershed. Nineteen habitat patches of high, or low relative fish abundance were delineated and monitored over a 13-month period. Seasonal habitat surveys quantified channel characteristics in each patch. Immigration and emigration were monitored using stationary and portable PIT-tag antennas along 2 km of stream, including mainstem and tributary habitats. In general, habitat patches that supported a high abundance of coastal cutthroat trout experienced less immigration and more consistent fish abundance. Mainstem study sections maintained the initial relative abundance patterns, but abundances in the tributary sections shifted during the study period. Abundances of PIT-tagged coastal cutthroat trout were consistent over time in mainstem habitats, even though some originally marked fish moved away. In tributary sections relative abundances were much more variable and few originally marked fish remained.

DISCIPLINE: Fisheries    STUDY: Hinkle Creek    TYPE: Theses    TAGS:

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