Risk-sensitive foraging by juvenile signal crayfish (Pacifastacus leniusculus)

2006 ◽  
Vol 84 (11) ◽  
pp. 1693-1697 ◽  
Author(s):  
C.A. Bondar ◽  
K. Zeron ◽  
John S. Richardson
Keyword(s):  
Feeding Behavior ◽  
Woody Debris ◽  
Food Selection ◽  
Cutthroat Trout ◽  
Pacifastacus Leniusculus ◽  
Food Type ◽  
Nutritional Requirements ◽  
Oncorhynchus Clarkii ◽  
Signal Crayfish ◽  
Risk Sensitive Foraging

Feeding behavior of carnivorous and herbivorous organisms is commonly explained in terms of nutritional requirements. However, feeding behavior of omnivorous organisms is difficult to predict and may not be based on nutritional requirements alone. To assess the plasticity of feeding behaviors exhibited by an omnivore, we conducted a feeding experiment using juvenile signal crayfish ( Pacifastacus leniusculus (Dana, 1852)), both alone and in the presence of conspecifics and predators. Crayfish were presented with three types of food (chironomids, mayflies, and woody debris) in experimental enclosures, and the food type consumed and time to consumption were recorded. Although the same overall food choice (chironomid larvae) was made in all trials, the time it took for the juvenile crayfish to make a food selection was longer in the presence of adult conspecifics (both male and female) and adult cutthroat trout ( Oncorhynchus clarkii (Richardson, 1836)). Food selection also took longer, although not significantly, in the presence of conspecific juvenile crayfish, and no changes in behavior were noted in the presence of young-of-the-year (YOY) cutthroat trout. The altered behavior of the juvenile crayfish observed in the presence of adult fish and crayfish can lead to context-dependent effects of this omnivore on its community. Ecologists must be increasingly aware that the feeding of omnivores may not be solely based on nutritional criteria.

Modulation of endogenous antioxidants by zinc and copper in signal crayfish (Pacifastacus leniusculus)

Chemosphere ◽  
2021 ◽  
pp. 129982
Author(s):  
Mark P. Gunderson ◽  
Hailey M. Boyd ◽  
Courtney I. Kelly ◽  
Isabela R. Lete ◽  
Quinlan R. McLaughlin
Keyword(s):  
Pacifastacus Leniusculus ◽  
Signal Crayfish ◽  
Endogenous Antioxidants

Metabolic performance and thermal preference of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi and non-native trout across an ecologically relevant range of temperatures

2021 ◽  
Author(s):  
Camille J. Macnaughton ◽  
Travis C. Durhack ◽  
Neil J. Mochnacz ◽  
Eva C. Enders
Keyword(s):  
Brook Trout ◽  
Cold Water ◽  
Cutthroat Trout ◽  
Intermittent Flow ◽  
Performance Curve ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Thermal Niche ◽  
Preferred Temperatures ◽  
Metabolic Performance

The physiology and behaviour of fish are strongly affected by ambient water temperature. Physiological traits related to metabolism, such as aerobic scope (AS), can be measured across temperature gradients and the resulting performance curve reflects the thermal niche that fish can occupy. We measured AS of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) at 5, 10, 15, 20, and 22°C and compared temperature preference (Tpref) of the species to non-native Brook Trout, Brown Trout, and Rainbow Trout. Intermittent-flow respirometry experiments demonstrated that metabolic performance of Westslope Cutthroat Trout was optimal at ~15 °C and decreased substantially beyond this temperature, until lethal temperatures at ~25 °C. Adjusted preferred temperatures across species (Tpref) were comparatively high, ranging from 17.8-19.9 °C, with the highest Tpref observed for Westslope Cutthroat Trout. Results suggest that although Westslope Cutthroat Trout is considered a cold-water species, they do not prefer or perform as well in cold water (≤ 10°C), thus, can occupy a warmer thermal niche than previously thought. The metabolic performance curve (AS) can be used to develop species‐specific thermal criteria to delineate important thermal habitats and guide conservation and recovery actions for Westslope Cutthroat Trout.

scholarly journals Size-mediated, density-dependent cannibalism in the signal crayfish Pacifastacus leniusculus (Dana, 1852) (Decapoda, Astacidea), an invasive crayfish in Britain

Crustaceana ◽  
2017 ◽  
Vol 90 (4) ◽  
pp. 417-435 ◽  
Author(s):  
R. J. Houghton ◽  
C. Wood ◽  
X. Lambin
Keyword(s):  
Relative Size ◽  
Pacifastacus Leniusculus ◽  
Gut Contents ◽  
Size Distributions ◽  
Signal Crayfish ◽  
Density Dependent ◽  
Invasive Crayfish ◽  
The Relationship ◽  
Best Fit

The role of cannibalism in crayfish populations is not well understood, despite being a potentially key density-dependent process underpinning population dynamics. We studied the incidence of cannibalism in an introduced signal crayfish Pacifastacus leniusculus population in a Scottish lowland river in September 2014. Animals were sampled using six different sampling techniques simultaneously, revealing variable densities and size distributions across the site. Cannibalism prevalence was estimated by analysing the gut contents of crayfish >20 mm CL for the presence of crayfish fragments, which was found to be 20% of dissected individuals. When seeking evidence of relationships between the sizes of cannibals and ‘prey’, the density of conspecifics <56% the size of a dissected individual yielded the best fit. The relationship between cannibalism probability and crayfish size and density was equally well described by three different metrics of crayfish density. Cannibalism increased with crayfish size and density but did not vary according to sex. These results suggest that large P. leniusculus frequently cannibalize smaller (prey) conspecifics, and that the probability of cannibalism is dependent upon the relative size of cannibal-to-prey and the density of the smaller crayfish. We suggest that removing large individuals, as targeted by many traditional removal techniques, may lead to reduced cannibalism and therefore a compensatory increase in juvenile survival.

scholarly journals Hybridization of Snake River Cutthroat in the Lower Gros Ventre River

2006 ◽  
Vol 30 ◽  
pp. 110-113
Author(s):  
Ryan Kovach ◽  
Lisa Eby
Keyword(s):  
Exotic Species ◽  
National Park ◽  
Cutthroat Trout ◽  
Snake River ◽  
Oncorhynchus Clarki ◽  
Oncorhynchus Clarkii ◽  
Grand Teton National Park ◽  
Water Diversions ◽  
Yellowstone Cutthroat Trout ◽  
Special Concern

The cutthroat trout Oncorhynchus clarki is Wyoming's only native trout. The Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) is designated as a "species of special concern" by a number of agencies and conservation groups. Although the Yellowstone cutthroat trout has recently avoided federal listing because of robust headwater populations (USFWS 2006), they face continued threats across their range. The fine-spotted Snake River native trout is a morphologically divergent ecotype of the Yellowstone subspecies, although it is not genetically distinguishable (Allendorf and Leary 1988, Novak et al. 2005). The Gros Ventre, an important tributary of the Snake River located partially in Grand Teton National Park, historically supported robust populations of fine­ spotted Snake River cutthroat trout. Principal threats to Gros Ventre native trout, especially in the lower end of the drainage within the park boundaries, include both water diversions (loss of water and fish into irrigation ditches) and presence of exotic species.

scholarly journals Dynamics of range expansion of the signal crayfish (Pacifastacus leniusculus) in a recently invaded region in Croatia

2017 ◽  
Vol 12 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Sandra Hudina ◽  
Petra Kutleša ◽  
Krešimira Trgovčić ◽  
Aljoša Duplić
Keyword(s):  
Range Expansion ◽  
Pacifastacus Leniusculus ◽  
Signal Crayfish
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