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• 1. [Article] Stream habitat utilization and behavior of sympatric and allopatric wild cutthroat trout (Salmo clarki) and hatchery coho salmon (Oncorhynchus kitsutch)

  The behavior and stream habitat utilization of juvenile hatchery-reared coho salmon (Ovicozihynchus kisutch) and wild cutthroat trout (Salmo clarki) were examined to assess the nature of interactions between ...

  Citation × Citation Citation Abstract Copy Title: Stream habitat utilization and behavior of sympatric and allopatric wild cutthroat trout (Salmo clarki) and hatchery coho salmon (Oncorhynchus kitsutch) Author: Jacobs, Steven Edward The behavior and stream habitat utilization of juvenile hatchery-reared coho salmon (Ovicozihynchus kisutch) and wild cutthroat trout (Salmo clarki) were examined to assess the nature of interactions between the species potentially resulting from introductions of hatchery coho salmon in streams. Habitat utilization was monitored in Mill Creek, Polk Co., Oregon by manipulating the composition of fish within three study sections to include either allopatric or sympatric populations of hatchery coho salmon and wild cutthroat trout. In allopatry, coho salmon and cutthroat trout selected feeding microhabitat that was similar in physical characteristics and exhibited extensive dietary overlap. When the two species occurred in sympatry, feeding microhabitat used by coho salmon was altered, however, that of cutthroat trout was comparable to allopatric cutthroat trout. No discernable differences in dietary composition between allopatric and sympatric fish were detected. While allopatric cutthroat trout always gained mass. ailopatric coho salmon always lost mass. Stomach fullness indices were higher for allopatric cutthroat trout than allopatric coho salmon. Sympatric cutthroat trout had comparable or greater gains of mass, indices of stomach fullness, and hepatic glycogen reserves relative to allopatric cutthroat trout. Conversely, sympatric coho salmon had greater losses of mass, reduced hepatic glycogen reserves, and apparently lower indices of stomach fullness than allopatric salmon. Behavioral observations made through the use of an in-stream viewing chamber in Berry Creek, Benton Co., Oregon, indicated that in allopatry populations of hatchery coho salmon and wild cutthroat trout were structured as linear dominance hierarchies that were organized by quantitatively and qualitatively similar aggressive interactions. In sympatry, however, cutthroat trout were more aggressive and socially dominant to coho salmon. The shift in use of micro-habitat and reduction in habitat utilization effectiveness of hatchery coho salmon in the presence of cutthroat trout can, thus, be interpreted to occur as a result of interference competition mediated through interspecific aggression. Title: Stream habitat utilization and behavior of sympatric and allopatric wild cutthroat trout (Salmo clarki) and hatchery coho salmon (Oncorhynchus kitsutch) Author: Jacobs, Steven Edward The behavior and stream habitat utilization of juvenile hatchery-reared coho salmon (Ovicozihynchus kisutch) and wild cutthroat trout (Salmo clarki) were examined to assess the nature of interactions between the species potentially resulting from introductions of hatchery coho salmon in streams. Habitat utilization was monitored in Mill Creek, Polk Co., Oregon by manipulating the composition of fish within three study sections to include either allopatric or sympatric populations of hatchery coho salmon and wild cutthroat trout. In allopatry, coho salmon and cutthroat trout selected feeding microhabitat that was similar in physical characteristics and exhibited extensive dietary overlap. When the two species occurred in sympatry, feeding microhabitat used by coho salmon was altered, however, that of cutthroat trout was comparable to allopatric cutthroat trout. No discernable differences in dietary composition between allopatric and sympatric fish were detected. While allopatric cutthroat trout always gained mass. ailopatric coho salmon always lost mass. Stomach fullness indices were higher for allopatric cutthroat trout than allopatric coho salmon. Sympatric cutthroat trout had comparable or greater gains of mass, indices of stomach fullness, and hepatic glycogen reserves relative to allopatric cutthroat trout. Conversely, sympatric coho salmon had greater losses of mass, reduced hepatic glycogen reserves, and apparently lower indices of stomach fullness than allopatric salmon. Behavioral observations made through the use of an in-stream viewing chamber in Berry Creek, Benton Co., Oregon, indicated that in allopatry populations of hatchery coho salmon and wild cutthroat trout were structured as linear dominance hierarchies that were organized by quantitatively and qualitatively similar aggressive interactions. In sympatry, however, cutthroat trout were more aggressive and socially dominant to coho salmon. The shift in use of micro-habitat and reduction in habitat utilization effectiveness of hatchery coho salmon in the presence of cutthroat trout can, thus, be interpreted to occur as a result of interference competition mediated through interspecific aggression. Close

• 2. [Article] Habitat use, movement, and life history variation of coastal cutthroat trout, Oncorhynchus clarkii clarkii, in the Salmon River estuary, Oregon

  Anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii may be highly dependent on estuaries, passing through them multiple times during their lifetime. However, few studies have investigated estuarine ...

  Citation × Citation Citation Abstract Copy Title: Habitat use, movement, and life history variation of coastal cutthroat trout, Oncorhynchus clarkii clarkii, in the Salmon River estuary, Oregon Author: Krentz, Lisa K. Anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii may be highly dependent on estuaries, passing through them multiple times during their lifetime. However, few studies have investigated estuarine use by coastal cutthroat trout and it is often thought that estuaries serve primarily as migration corridors rather than rearing areas. We used both PIT tag and acoustic tracking techniques in 2002 and 2003 to investigate habitat use, movement, and life history variation within the population of coastal cutthroat trout in the Salmon River estuary, Oregon. Evidence of site fidelity was observed in both the PIT-tagged and acoustically tagged fish, with 70% of PIT tagged fish being recaptured at their previous capture site and most acoustically tagged fish residing in one location for at least 25 days. Ninety percent of fish relocated 1.7 km upstream or downstream showed directional movement toward the original site of capture, and half of those eventually took up residence there. Cutthroat trout used main channel sites more frequently than marsh channel sites, and deeper sites more frequently than shallower sites. Contrary to published results for most other coastal populations, Salmon River cutthroat trout rear in the estuary for much of the year. We identified two main life history types: an “ocean migrant” form that migrates rapidly through the estuary and out to sea, and an “estuarine resident” form that resides in the estuary for the spring and summer. In addition, we found evidence of other life history types: coastal cutthroat trout that rear mainly in the estuary but make brief forays into the near shore ocean, and some that rear in the estuary throughout winter. We saw no difference in mean length at tagging between ocean migrants and estuarine residents, suggesting that the stimulation for migrating to the ocean was not size related. Half of the acoustically tagged fish exhibited the estuarine life history type. We compared growth rates of ocean migrants and estuarine residents by classifying PIT-tagged fish into life history types based on their recapture history. We found no evidence of a growth advantage for ocean migrants, although sample size was small. This study suggests that the estuarine life history is an important migratory behavior within the continuum of life histories for coastal cutthroat trout in the Salmon River. Our results imply that conservation of coastal cutthroat trout may depend on recovery and maintenance of suitable estuarine rearing habitat. Title: Habitat use, movement, and life history variation of coastal cutthroat trout, Oncorhynchus clarkii clarkii, in the Salmon River estuary, Oregon Author: Krentz, Lisa K. Anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii may be highly dependent on estuaries, passing through them multiple times during their lifetime. However, few studies have investigated estuarine use by coastal cutthroat trout and it is often thought that estuaries serve primarily as migration corridors rather than rearing areas. We used both PIT tag and acoustic tracking techniques in 2002 and 2003 to investigate habitat use, movement, and life history variation within the population of coastal cutthroat trout in the Salmon River estuary, Oregon. Evidence of site fidelity was observed in both the PIT-tagged and acoustically tagged fish, with 70% of PIT tagged fish being recaptured at their previous capture site and most acoustically tagged fish residing in one location for at least 25 days. Ninety percent of fish relocated 1.7 km upstream or downstream showed directional movement toward the original site of capture, and half of those eventually took up residence there. Cutthroat trout used main channel sites more frequently than marsh channel sites, and deeper sites more frequently than shallower sites. Contrary to published results for most other coastal populations, Salmon River cutthroat trout rear in the estuary for much of the year. We identified two main life history types: an “ocean migrant” form that migrates rapidly through the estuary and out to sea, and an “estuarine resident” form that resides in the estuary for the spring and summer. In addition, we found evidence of other life history types: coastal cutthroat trout that rear mainly in the estuary but make brief forays into the near shore ocean, and some that rear in the estuary throughout winter. We saw no difference in mean length at tagging between ocean migrants and estuarine residents, suggesting that the stimulation for migrating to the ocean was not size related. Half of the acoustically tagged fish exhibited the estuarine life history type. We compared growth rates of ocean migrants and estuarine residents by classifying PIT-tagged fish into life history types based on their recapture history. We found no evidence of a growth advantage for ocean migrants, although sample size was small. This study suggests that the estuarine life history is an important migratory behavior within the continuum of life histories for coastal cutthroat trout in the Salmon River. Our results imply that conservation of coastal cutthroat trout may depend on recovery and maintenance of suitable estuarine rearing habitat. Close

• 3. [Article] Engaging Recreational Fishers in Management and Conservation: Global Case Studies

  Globally, the number of recreational fishers is sizeable and increasing in many countries. Associated with this trend is the potential for negative impacts on fish stocks through exploitation or management ...

  Citation × Citation Citation Abstract Copy Title: Engaging Recreational Fishers in Management and Conservation: Global Case Studies Author: Granek, Elise F., Madin, Elizabeth M.P., Brown, M. A., Figueira, Will F., Cameron, Darren S., Hogan, Zeb, Kristianson, Gerry, de Villiers, Pierre, Williams, Jack E., Post, John R., Zahn, S., Arlinghaus, R. Year: 2008 Globally, the number of recreational fishers is sizeable and increasing in many countries. Associated with this trend is the potential for negative impacts on fish stocks through exploitation or management measures such as stocking and introduction of non-native fishes. Nevertheless, recreational fishers can be instrumental in successful fisheries conservation through active involvement in, or initiation of, conservation projects to reduce both direct and external stressors contributing to fishery declines. Understanding fishers’ concerns for sustained access to the resource and developing methods for their meaningful participation can have positive impacts on conservation efforts. We examined a suite of case studies that demonstrate successful involvement of recreational fishers in conservation and management activities that span developed and developing countries, temperate and tropical regions, marine and freshwater systems, and open- and closedaccess fisheries. To illustrate potential benefits and challenges of involving recreational fishers in fisheries management and conservation, we examined the socioeconomic and ecological contexts of each case study. We devised a conceptual framework for the engagement of recreational fishers that targets particular types of involvement (enforcement, advocacy, conservation, management design [type and location], research, and monitoring) on the basis of degree of stakeholder stewardship, scale of the fishery, and source of impacts (internal or external). These activities can be enhanced by incorporating local knowledge and traditions, taking advantage of leadership and regional networks, and creating collaborations among various stakeholder groups, scientists, and agencies to maximize the probability of recreational fisher involvement and project success. Title: Engaging Recreational Fishers in Management and Conservation: Global Case Studies Author: Granek, Elise F., Madin, Elizabeth M.P., Brown, M. A., Figueira, Will F., Cameron, Darren S., Hogan, Zeb, Kristianson, Gerry, de Villiers, Pierre, Williams, Jack E., Post, John R., Zahn, S., Arlinghaus, R. Year: 2008 Globally, the number of recreational fishers is sizeable and increasing in many countries. Associated with this trend is the potential for negative impacts on fish stocks through exploitation or management measures such as stocking and introduction of non-native fishes. Nevertheless, recreational fishers can be instrumental in successful fisheries conservation through active involvement in, or initiation of, conservation projects to reduce both direct and external stressors contributing to fishery declines. Understanding fishers’ concerns for sustained access to the resource and developing methods for their meaningful participation can have positive impacts on conservation efforts. We examined a suite of case studies that demonstrate successful involvement of recreational fishers in conservation and management activities that span developed and developing countries, temperate and tropical regions, marine and freshwater systems, and open- and closedaccess fisheries. To illustrate potential benefits and challenges of involving recreational fishers in fisheries management and conservation, we examined the socioeconomic and ecological contexts of each case study. We devised a conceptual framework for the engagement of recreational fishers that targets particular types of involvement (enforcement, advocacy, conservation, management design [type and location], research, and monitoring) on the basis of degree of stakeholder stewardship, scale of the fishery, and source of impacts (internal or external). These activities can be enhanced by incorporating local knowledge and traditions, taking advantage of leadership and regional networks, and creating collaborations among various stakeholder groups, scientists, and agencies to maximize the probability of recreational fisher involvement and project success. Close