Perry, Stephen

Impacts of Exotic Rainbow Trout on Habitat Use by Native Juvenile Salmonid Species at an Early Invasive Stage: The detrimental impact of introduced Rainbow Trout Oncorhynchus mykiss on native communities has been well documented around the world. Previous studies have focused on streams where the invasion has been successful and the species is fully established. In eastern Quebec, the invasion of Rainbow Trout is an ongoing process and, for now, there are few established populations. The presence of two native salmonids in these rivers, Atlantic Salmon Salmo salar and Brook Trout Salvelinus fontinalis, implies a risk of competition for habitat, despite the relatively low density of the Rainbow Trout populations, as all three species are known to use similar resources. In order to evaluate the strength of the interaction between the invading fish and the native species, we sampled nine rivers (five with Rainbow Trout and four free of Rainbow Trout) and characterized the habitat used by the three salmonids at the juvenile stage. River-scale analysis revealed that in invaded rivers, Rainbow Trout were associated with habitats characterized by closer proximity to the shoreline and by increasing shoreline cover. Estimates of habitat niche overlap integrating depth, water velocity, and substrate size revealed that niche overlap between Brook Trout and Atlantic Salmon significantly increased in the presence of Rainbow Trout. Furthermore, the two indigenous species preferred full cover in the absence of Rainbow Trout but in the presence of Rainbow Trout, which also preferred full cover, the indigenous species moved to more open habitats. Rainbow Trout showed a high growth rate, despite a size disadvantage at the beginning of the growing season, as compared with Atlantic Salmon and Brook Trout. It thus appears that even at an early stage of invasion, when its density is still low, Rainbow Trout significantly impact native salmonids.
Located in Science and Data / Brook Trout Related Publications
Individual behaviour and resource use of thermally stressed brook trout Salvelinus fontinalis portend the conservation potential of thermal refugia: Individual aggression and thermal refuge use were monitored in brook trout Salvelinus fontinalis in a controlled laboratory to determine how fish size and personality influence time spent in forage and thermal habitat patches during periods of thermal stress. On average, larger and more exploratory fish initiated more aggressive interactions and across all fish there was decreased aggression at warmer temperatures. Individual personality did not explain changes in aggression or habitat use with increased temperature; however, larger individuals initiated comparatively fewer aggressive interactions at warmer temperatures. Occupancy of forage patches generally declined as ambient stream temperatures approached critical maximum and fish increased thermal refuge use, with a steeper decline in forage patch occupancy observed in larger fish. These findings suggest that larger individuals may be more vulnerable to stream temperature rise. Importantly, even at thermally stressful temperatures, all fish periodically left the thermal refuge to forage. This indicates that the success of refugia at increasing population survival during periods of stream temperature rise may depend on the location of thermal refugia relative to forage locations within the larger habitat mosaic. These results provide insights into the potential for thermal refugia to improve population survival and can be used to inform predictions of population vulnerability to climate change.
Located in Science and Data / Brook Trout Related Publications
Is motivation important to brook trout passage through culverts?: Culverts can restrict movement of stream-dwelling fish. Motivation to enter and ascend these structures is an essential precursor for successful passage. However, motivation is challenging to quantify. Here, we use attempt rate to assess motivation of 447 brook trout (Salvelinus fontinalis) entering three culverts under a range of hydraulic, environmental, and biological conditions. A passive integrated transponder system allowed for the identification of passage attempts and success of individual fish. Attempt rate was quantified using time-to-event analysis allowing for time-varying covariates and recurrent events. Attempt rate was greatest during the spawning period, at elevated discharge, at dusk, and for longer fish. It decreased during the day and with increasing number of conspecifics downstream of the culvert. Results also show a positive correlation between elevated motivation and successful passage. This study enhances understanding of factors influencing brook trout motivation to ascend culverts and shows that attempt rate is a dynamic phenomenon, variable over time and among individuals. It also presents methods that could be used to investigate other species’ motivation to pass natural or anthropogenic barriers.
Located in Science and Data / Brook Trout Related Publications
Jam Black Brook Culvert Replacement, ME_FY12 Project: The goals of the project were: (1) To remove an obstruction to upstream fish passage for brook trout, Atlantic salmon and other resident and migratory fish. (2) To restore access to 9.8 miles of stream habitat upstream of the obstruction. (3) To restore natural sediment and woody debris transport through the crossing site. (4) To improve flood capacity at the Magog Road crossing, reducing the risk of debris jams or overtopping the road. (5) To provide a demonstration site in mid‐coast Maine for an appropriate stream crossing developed in cooperation with the municipality.
Located in Projects / Project Completion Reports
January 2012 NFH Board Meeting Book: This document contains materials associated with the National Fish Habitat Board's January 12, 2012 meeting that was conducted by teleconference.
Located in About EBTJV / National Fish Habitat Board Meetings / 2012 NFH Board Meetings
January 2013 NFH Board Meeting Book: This document contains materials associated with the National Fish Habitat Board's January 16, 2013 meeting that was conducted by teleconference.
Located in About EBTJV / National Fish Habitat Board Meetings / 2013 NFH Board Meetings
January 2014 NFH Board Meeting Book: This document contains materials associated with the National Fish Habitat Board's January 15, 2014 meeting that was conducted by teleconference.
Located in About EBTJV / National Fish Habitat Board Meetings / 2014 NFH Board Meetings
January 2015 NFH Board Meeting Book: This document contains materials associated with the National Fish Habitat Board's January 15, 2015 meeting that was conducted by teleconference.
Located in About EBTJV / National Fish Habitat Board Meetings / 2015 NFH Board Meetings
January 2016 NFH Board Meeting Book: This document contains materials associated with the National Fish Habitat Board's January 20, 2016 meeting that was conducted by teleconference.
Located in About EBTJV / National Fish Habitat Board Meetings / 2016 NFH Board Meetings
January 2017 NFH Board Meeting Book: This document contains materials associated with the National Fish Habitat Board's January 18, 2017 meeting that was conducted by teleconference.
Located in About EBTJV / National Fish Habitat Board Meetings / 2017 NFH Board Meetings

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