Individual differences exceed species differences in the movements of a river fish community

Repeatable individual differences often account for large proportions of intraspecific variation in animal movements. However, meta-population models have continued to rely on single species-level and season-specific species-level means for movement prediction. Here, we test the hypothesis that repeatable individual differences can account for a similar proportion of movement distance variation as species differences. We used radio telemetry to generate repeated measures of movement from 504 hetero-specific fish. We tracked 5 large bodied fish species (Salvelinus confluentus, Oncorhynchus mykiss, Prosopium williamsoni, Thymallus arcticus, and Sander vitreus) in the upper reaches of the Peace River, British Columbia, Canada, over 8 years. We applied a hierarchical framework to partition repeatability of movement distances at the intra- and interspecific biological levels, and among short-term (within-season) and long-term (across seasons and years) temporal levels. Our results show that long-term movement distance repeatability was higher at the intraspecific level than at the interspecific level, demonstrating that animal personality can account for more variation in movement than species differences. These findings provide a novel, community level demonstration of the importance of individual variation, highlighting the predictive gains associated with a shift in the focus of spatial ecology, away from species mean and seasonal species-level mean predictive approaches, towards a spatial behavioral types-based predictive approach

Osmoregulatory, metabolic and nutritional condition of summer-run male Chinook salmon in relation to their fate and migratory behavior in a regulated river

We studied the migratory success of male summer-run Chinook salmon Oncorhynchus tshawytscha in the Puntledge River on Canada’s Vancouver Island over a 3 yr period using biotelemetry and non-lethal physiological biopsy. Principal component analysis was used to group co-varying physiological variables prior to comparing fish with different migratory behaviors (e.g. migration rate, holding times) and fate (migration and spawning success). Fish with low levels of endogenous energy stores (total protein, cholesterol, and triglycerides) and dietary minerals (calcium, magnesium, and phosphorus) at the time of sampling were found to subsequently ascend the most upstream natural barrier (Nib Falls) significantly faster than fish with higher levels. Fate was weakly associated with several physiological characteristics; successful migrants had significantly higher hematocrit values and significantly lower plasma K+ relative to failed migrants, suggesting that fish condition at river entry can influence subsequent behavior. Our results indicate that physiological and nutritional condition can influence adult migrating male summer-run Chinook salmon, but we did not find a physiological profile that could explain all behaviors and fates observed. This study represents one of the first to apply conservation physiology tools to study an imperiled river fish population."Funding for this project was provided by BC Hydro’s Water Use Planning, and the DFO Environmental Watch Program. C.T.H. and M.R.D. were each supported by an Alexander Graham Bell Canada Graduate Scholarship from NSERC.

Turbine entrainment and passage of potadromous fish through hydropower dams: Developing conceptual frameworks and metrics for moving beyond turbine passage mortality

Potadromous fishes are vulnerable to involuntary entrainment through hydropower turbines. However, turbines can also provide a downstream passage route for potadromous fish. Here, we review evidence for turbine entrainment and passage in potadromous fish, and evaluate the effects of these processes on upstream and downstream populations. We develop conceptual frameworks and metrics to quantify vulnerability to turbine entrainment removals, and to quantify the efficiency of turbines as a downstream passage route. We highlight factors that influence these processes and provide case-studies demonstrating their applicability. We found that juvenile potadromous fi