Selection of Positions by Drift-Feeding Salmonids in Dominance Hierarchies: Model and Test for Arctic Grayling (Thymallus arcticus) in Subarctic Mountain Streams, Interior Alaska

1992 ◽  
Vol 49 (10) ◽  
pp. 1999-2008 ◽  
Author(s):  
Nicholas F. Hughes
Keyword(s):  
Bottom Topography ◽  
Lateral Diffusion ◽  
Distribution Patterns ◽  
Mountain Stream ◽  
Physical Habitat ◽  
Dominance Hierarchies ◽  
Arctic Grayling ◽  
Drift Feeding ◽  
Stream Salmonids ◽  
Thymallus Arcticus

In this work I describe a model to predict position choice by each individual in a dominance hierarchy of drift-feeding stream salmonids. This is an adaptation of Hughes and Dill's model (1990. Can. J. Fish. Aquat. Sci. 47: 2039–2048) of position choice by solitary fish. I have included the effect that prey consumption, lateral diffusion of drifting invertebrates, and entry of invertebrates into the drift have on the density of prey downstream of feeding fish and the restrictions that dominant fish place on freedom of choice by their subordinates. l assume that each fish chooses the most profitable position that its rank in the hierarchy will allow. There was an encouraging match between the distribution patterns predicted by the model and the distribution patterns actually adopted by Arctic grayling (Thymallus arcticus) in two pools of a mountain stream. This result suggests that Arctic grayling locate and rank positions based on their profitability. The predictions of reduced models, and the location of positions in relation to bottom topography and current flow, suggest that the physical habitat forms the template for distribution patterns by determining the location and ranking of the most profitable positions.

Ranking of Feeding Positions by Drift-Feeding Arctic Grayling (Thymallus arcticus) in Dominance Hierarchies

1992 ◽  
Vol 49 (10) ◽  
pp. 1994-1998 ◽  
Author(s):  
Nicholas F. Hughes
Keyword(s):  
Dominance Hierarchy ◽  
Field Experiments ◽  
Dominance Rank ◽  
Mountain Stream ◽  
Fish Length ◽  
Dominance Hierarchies ◽  
Arctic Grayling ◽  
Perfect Correlation ◽  
Removal Experiments ◽  
Thymallus Arcticus

Field experiments in the pools of a mountain stream demonstrate that Arctic grayling (Thymallus arcticus) rank feeding positions according to desirability and that competition sorts fish so that the dominance rank of each individual matches the rank desirability of its position. Groups containing the same number of fish always occupied the same set of positions, and positions were added (in reverse order of desirability) as group size was increased; these results show that fish ranked positions. There was an almost perfect correlation between the dominance rank (measured as fish length) of each fish and the rank desirability of its position, suggesting that competition sorts fish among positions. This conclusion was strengthened by the results of sequential removal experiments in which the dominant fish was removed at the end of each day. After each removal the remaining fish almost always moved into the positions previously occupied by fish immediately above them in the dominance hierarchy.

Population processes responsible for larger-fish-upstream distribution patterns of Arctic grayling (Thymallus arcticus) in interior Alaskan runoff rivers

1999 ◽  
Vol 56 (12) ◽  
pp. 2292-2299 ◽  
Author(s):  
Nicholas F Hughes
Keyword(s):  
Distribution Pattern ◽  
Distribution Patterns ◽  
Long Distance ◽  
Arctic Grayling ◽  
Sedentary Population ◽  
Thymallus Arcticus ◽  
Population Processes ◽  
Analyse Data ◽  
A Minor ◽  
Size Gradient

During the summer months, Arctic grayling (Thymallus arcticus) in Alaskan streams adopt a larger-older-fish-upstream distribution pattern. In this paper, I analyse data from two large interior Alaskan rivers to determine how population processes maintain this size and age gradient. These analyses support the hypothesis that age-phased recruitment and growth-dependent movement are primarily responsible for this distribution pattern. Age-phased recruitment describes the way that the mean age of fish recruiting to a reach increases upstream, from ages 0-1 in the lower river to ages 3-7 in the headwaters. This process begins with the concentration of spawning fish, and the resultant fry, in the lower reaches of the river. Downstream movement during the first year of life further concentrates young fish in the lower river. Over time, the distribution of this cohort broadens steadily as individuals move further upstream, so that fish recruiting to headwater reaches are 3-7 years old. This process contributes to both size and age gradients. Growth-dependent movement magnifies the size gradient by sorting fast-growing fish into the upper river and slow-growing fish into the lower river. This sorting results from the fact that individuals making long-distance upstream movements tend to have grown particularly rapidly that year, while individuals making long-distance downstream movements tend to have grown especially slowly that year. I rejected the hypothesis that age and size gradients are the result of whole-stream gradients in growth or mortality acting on a sedentary population. However, there was some evidence that fish did grow more slowly in the lowest 40 km of one river, although this made only a minor contribution to the size gradient and growth rates were remarkably constant for the next 120 km. There was no suggestion that spatial variation in mortality rate contributes towards the size or age gradient, but natural and sampling variability could have obscured small but significant differences between reaches.

Mechanics of foraging success and optimal microhabitat selection in Alaskan Arctic grayling (Thymallus arcticus)

2019 ◽  
Vol 76 (5) ◽  
pp. 815-830 ◽  
Author(s):  
Bryan B. Bozeman ◽  
Gary D. Grossman
Keyword(s):  
Prey Capture ◽  
Water Velocity ◽  
Net Energy ◽  
Arctic Grayling ◽  
Drift Feeding ◽  
Reactive Distance ◽  
Negative Effect ◽  
Thymallus Arcticus ◽  
Alaskan Arctic ◽  
Size Rank

Most fishes residing in temperate streams in the Northern Hemisphere are drift-feeders. Despite this fact, little is known about the mechanisms of drift-feeding itself. We used Alaskan Arctic grayling (Thymallus arcticus), an abundant boreal drift-feeder, to examine the effects of water velocity on several aspects of drift-feeding behavior and test predictions of the Grossman et al. (2002) net energy intake model for microhabitat choice. Water velocity had a negative effect on prey capture, a positive effect on holding velocity, and little effect on reactive distance. We also found that dominance was a better predictor of prey capture success than size rank, although neither of these variables influenced holding velocity or reactive distance. The Grossman et al. (2002) model successfully predicted holding velocities of grayling in one Alaskan stream, but not another. Model failure might have occurred due to higher turbulence, increased predation, or interspecific competition with Dolly Varden (Salvelinus malma). These results help inform the study of habitat selection in drift-feeding fishes as well as management and conservation of Arctic grayling.

Energetic status and bioelectrical impedance modeling of Arctic grayling Thymallus arcticus in interior Alaska Rivers

2019 ◽  
Vol 102 (11) ◽  
pp. 1337-1349
Author(s):  
Jeffrey A. Falke ◽  
Lauren T. Bailey ◽  
Kevin M. Fraley ◽  
Michael J. Lunde ◽  
Andrew D. Gryska
Keyword(s):  
Bioelectrical Impedance ◽  
Arctic Grayling ◽  
Interior Alaska ◽  
Impedance Modeling ◽  
Thymallus Arcticus

scholarly journals Consumption of Shrews, Sorex spp., by Arctic Grayling, Thymallus arcticus

2004 ◽  
Vol 118 (1) ◽  
pp. 111 ◽  
Author(s):  
Jonathan W. Moore ◽  
G. J. Kenagy
Keyword(s):  
Stable Isotopes ◽  
Dietary Habits ◽  
Riparian Zones ◽  
Stream Fishes ◽  
Nitrogen Stable Isotopes ◽  
Arctic Grayling ◽  
Thymallus Arcticus ◽  
Southwestern Alaska

In an investigation of the dietary habits of Arctic Grayling (Thymallus arcticus) we found that two individuals out of 93 sampled in southwestern Alaska (approximately 59°N, 159°W) contained a total of five shrews (Sorex spp.). These shrews contained enriched levels of nitrogen stable isotopes, suggesting utilization of nutrients derived from salmon. We hypothesize that normally terrestrial shrews accidentally enter streams while foraging along the productive riparian zones of creeks with high densities of salmon. Shrews are apparently susceptible to opportunistic predation by resident stream fishes, including Arctic Grayling, when they enter the streams.

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