An experimental investigation of refuging behaviour in a minnow

1983 ◽  
Vol 61 (3) ◽  
pp. 666-672 ◽  
Author(s):  
Douglas F. Fraser
Keyword(s):  
Experimental Investigation ◽  
Age Groups ◽  
Diel Cycle ◽  
Foraging Efficiency ◽  
Semotilus Atromaculatus ◽  
Small Cover ◽  
Artificial Stream ◽  
Natural Stream ◽  
Risk Of Predation ◽  
Creek Chub

An artificial stream was used to experimentally investigate refuging behaviour in the creek chub (Semotilus atromaculatus). When shelters were limited, adults dispersed from and returned to the area of the stream containing shelter on a diel cycle. Thus, they exhibited refuging behaviour as defined by Hamilton and Watt (W. J. Hamilton and K. E. F. Watt. 1970. Refuging. Annu. Rev. Ecol. Syst. 1: 263–284). However, when shelters were unlimited, adults did not aggregate in one location, indicating that adult refuging is conditioned by the dispersal of suitable shelters and that it is not a communal process as in roosting birds. In contrast with adults, when shelters were limited, young creek chub did not refuge. The differences in behaviour of the two size–age groups are consistent with observations from the natural stream, in that young chub can utilize small cover objects such as submerged leaves or employ crypsis to escape detection, rendering them less dependent than adults on cover. Further, high densities of juveniles in refuge locations would reduce their foraging efficiency and increase the risk of predation by piscivorous adults.

Behavioral Response of Blacknose Dace (Rhinichthys atratulus) to Varying Densities of Predatory Creek Chub (Semotilus atromaculatus)

1984 ◽  
Vol 41 (2) ◽  
pp. 364-370 ◽  
Author(s):  
Douglas F. Fraser ◽  
Edward E. Emmons
Keyword(s):  
Behavioral Response ◽  
Water Levels ◽  
Semotilus Atromaculatus ◽  
Piscivorous Fish ◽  
Natural Stream ◽  
Rhinichthys Atratulus ◽  
Blacknose Dace ◽  
Creek Chub ◽  
Term Benefit

We investigated the behavioral response of juvenile blacknose dace (Rhinichthys atratulus) to varying levels of predation risk by varying the density of predatory creek chub (Semotilus atromaculatus) and amount of structure in compartments of an artificial field stream. When structure in predator locations was low, dace did not avoid predators during the day but did at night, responding equally regardless of predator density. When structure was increased, the strength of avoidance at night was dependent on both the amount of structure and density of predators. Predators in experimental compartments caused dace to move to other locations of the stream. By moving away from predators, dace gain a short-term benefit in avoiding predation and a long-term benefit by reducing the chance of becoming trapped in pools with piscivorous fish when water levels in a natural stream drop. However, this shift could reduce feeding if dace move to locations poor for foraging or high in density of dace.

Mechanisms responsible for the niche shift of brook charr, Salvelinus fontinalis Mitchill, when living sympatrically with creek chub, Semotilus atromaculatus Mitchill

1984 ◽  
Vol 62 (8) ◽  
pp. 1548-1555 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald
Keyword(s):  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Intraspecific Aggression ◽  
Brook Charr ◽  
Semotilus Atromaculatus ◽  
High Level ◽  
Gill Raker ◽  
Creek Chub ◽  
Study Laboratory

When brook charr, Salvelinus fontinalis Mitchill, are in allopatry in oligotrophic Québec lakes, they feed largely on macrobenthic invertebrates. However, when brook charr cooccur with creek chub, Semotilus atromaculatus Mitchill, they feed largely on zooplankton. In the present study, laboratory experiments showed that creek chub were more effective than brook charr in searching for hidden, patchily distributed prey. The searching efficiency of an individual chub feeding in a group was improved through social facilitation. In contrast, the high level of intraspecific aggression observed in brook charr prevents the formation of such feeding groups. In the laboratory, brook charr were able to displace creek chub from the food source because of interspecific aggression. Data are presented showing that chub are morphologically better adapted than charr to feed on benthos (subterminal orientation of the mouth and protrusible premaxillae), while the charr are better adapted than chub to feed on zooplankton (gill raker structure). Differences in feeding behaviour, morphology, and relative abundance between these species appear to be important in the observed niche shift of brook charr in nature.

Deep-sea foraging pathways: an analysis of randomness and resource exploitation

Paleobiology ◽  
1979 ◽  
Vol 5 (2) ◽  
pp. 107-125 ◽  
Author(s):  
Jennifer A. Kitchell
Keyword(s):  
Deep Sea ◽  
Trace Fossil ◽  
Empirical Modeling ◽  
The Arctic ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Resource Exploitation ◽  
Foraging Patterns ◽  
Risk Of Predation ◽  
Random Behavior

The foraging paradigm of trace fossil theory has historically accorded random behavior to non-food-limited deposit-feeders and non-random behavior to food-limited feeders. A series of randomness measures derived from empirical modeling, simulation modeling, stochastic modeling and probability theory applied to foraging patterns observed in deep-sea bottom photographs from the Arctic and Antarctic yielded a behavioral continuum of increasing non-randomness. A linear regression of trace positions along the continuum to bathymetric data did not substantiate the optimal foraging efficiency-depth dependence model of trace fossil theory, except that all traces exhibited a greater optimization than that of simulated random foraging. It is hypothesized that optimization as evidenced by non-random foraging strategies represents maximization of the cost/benefit ratio of resource exploitation to risk of predation and that individual foraging patterns reflect an exploration response to the morphometry of a patchily distributed food resource. Differential predation and competition may account for the co-occurrence of random and non-random strategies within the same bathymetric zone.

scholarly journals Possums in the park: efficient foraging under the risk of predation or of competition?

2000 ◽  
Vol 48 (2) ◽  
pp. 155 ◽  
Author(s):  
Eve McDonald-Madden ◽  
Lian K. Akers ◽  
Deena J. Brenner ◽  
Sarah Howell ◽  
Blair W. Patullo ◽  
...  
Keyword(s):  
Urban Population ◽  
Foraging Behaviour ◽  
Field Experiments ◽  
Foraging Efficiency ◽  
Trichosurus Vulpecula ◽  
Initial Amount ◽  
Trade Off ◽  
Food Items ◽  
Risk Of Predation

Many eutherian mammals adjust their foraging behaviour according to the presence or threat of predators. Here, we examine experimentally whether an urban population of brushtail possums, Trichosurus vulpecula, similarly adjust their foraging behaviour. Our field experiments manipulated the quantity of food items in artificial feeders placed at different distances from trees. These experiments showed that the possums remained longer at feeders placed far from the trees, but their foraging behaviour did not change with the initial amount of food. The scanning behaviour of possums did not simply increase with distance from the trees, as predicted from studies of other vertebrates. Nevertheless, the number of physical conflicts between individuals increased as the amount of available food decreased. These data suggest that the changes in the foraging behaviour of the possums in this population do not reflect a simple trade-off between foraging efficiency and the risk of predation or competition.

scholarly journals Multiple areas of acute vision in two freshwater teleosts, the creek chub, Semotilus atromaculatus (Mitchill) and the cutlips minnow, Exoglossum maxillingua (Lesueur)

1994 ◽  
Vol 72 (4) ◽  
pp. 721-730 ◽  
Author(s):  
Shaun P. Collin ◽  
M. Ather Ali
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cell Layer ◽  
Cell Layer ◽  
Resolving Power ◽  
Retinal Ganglion ◽  
Semotilus Atromaculatus ◽  
Upper Limits ◽  
Close Phylogenetic Relationship ◽  
Creek Chub ◽  
Freshwater Teleosts

The topography of Nissl-stained cells within the retinal ganglion cell layer is examined in two closely related freshwater teleosts from the family Cyprinidae. Regardless of the close phylogenetic relationship and the sympatric habitats of the two species, pronounced differences in the number and position of areas of increased cell density are observed in their retinae. in the creek chub, Semotilus atromaculatus, a midwater crepuscular feeder, three retinal specializations or areae centrales are identified in the dorsonasal, nasal, and temporal regions of the retina. In the cutlips minnow, Exoglossum maxillingua, a benthic diurnal feeder, two areae centrales are identified in temporal and nasal retina. The upper limits of the spatial resolving power of each species are calculated from the spacing of cells within the ganglion cell layer. Differences in the arrangement of isodensity contours appear to reflect the symmetry of each species' visual environment. The development and significance of up to three visually acute zones are discussed.

Growth, maturation, and apparent and absolute fecundity of creek chub, Semotilus atromaculatus (Mitchill), in the Kawartha Lakes Region, Ontario

1977 ◽  
Vol 55 (5) ◽  
pp. 843-846 ◽  
Author(s):  
P. M. Powles ◽  
Douglas Parker ◽  
Ronald Reid
Keyword(s):  
Growth Rate ◽  
Semotilus Atromaculatus ◽  
Absolute Fecundity ◽  
Weight Relationship ◽  
Creek Chub

No difference in growth rate occurred between two study streams, but male creek chub grew more rapidly than females, to a maximum reached at 7 years of age. Walfords were as follows: y = 4.8 TL + 0.810x, females; y = 3.5 TL + 0.792x, males. The length–weight relationship, W = −3.609 + 2.925 log L (TL), derived in the fall, was, as expected, somewhat below the spring relationship from an Illinois study. Kawartha creek chub M50 values were 6.0 TL ± 0.83 cm (males) and 6.54 ± 0.18 cm (females). Relative or apparent fecundity (fall egg count) was F = 71.9 + 136W and total or absolute fecundity (just before spawning) was virtually similar to other areas at F = 61.6 + 91.8W.

Alarm cue specificity and response ontogeny in juvenile rainbow trout (Oncorhynchus mykiss)

Behaviour ◽  
2017 ◽  
Vol 154 (3) ◽  
pp. 377-385 ◽  
Author(s):  
Marianna E. Horn ◽  
Douglas P. Chivers
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Chemical Cues ◽  
Life Stage ◽  
Age Groups ◽  
Alarm Cues ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Risk Of Predation ◽  
Threat Cues ◽  
Two Age Groups

Many aquatic prey animals release chemical cues upon being captured by a predator. These chemical cues, referred to as alarm cues, may act to warn nearby individuals of danger. For the cues to be useful, fish must be able to discern if they are indicative of a real threat; cues from conspecifics in different age groups may be irrelevant due to size- and habitat-related shifts in predation risk. We test the response of newly-hatched rainbow trout,Oncorhynchus mykiss, to three concentrations of alarm cues from conspecifics from two age groups: newly-hatched versus six-month-old juveniles. Newly-hatched trout demonstrated a significant fright response to all three concentrations of alarm cues, but showed no difference in strength of response based on either concentration or age of the cue donor. We propose that the newly-hatched trout did not respond differently because of the high risk of predation that they face during this life stage.

Some little-known and new protozoan parasites of fish from Lake Sasajewun, Algonquin Park, Ontario

1989 ◽  
Vol 67 (6) ◽  
pp. 1372-1379 ◽  
Author(s):  
Jiří Lom ◽  
Sherwin S. Desser ◽  
Iva Dyková
Keyword(s):  
Tissue Specificity ◽  
Polar Filament ◽  
Lepomis Gibbosus ◽  
Renal Tubules ◽  
Protozoan Parasites ◽  
Sporocyst Residuum ◽  
Semotilus Atromaculatus ◽  
Ictalurus Nebulosus ◽  
The Common ◽  
Creek Chub

One hundred and twenty-six fish of eight species, taken from Lake Sasajewun, Ontario, were examined for protozoan parasites. Detailed descriptions are given for Sphaerospora diminuta Li and Desser from the pumpkinseed, Lepomis gibbosus, and for Goussia degiustii Molnar and Fernando from the common shiner, Notropis cornutus. Oocysts of G. degiustii are pleomorphic and exhibit low tissue specificity. Goussia freemani Molnar and Fernando from the kidney of N. cornutus is tentatively synonymized with Goussia leucisci Shulman and Zaika. Two new species of Sphaerospora are described: Sphaerospora paulini n.sp. from the renal tubules of creek chub, Semotilus atromaculatus, with spherical spores 8.1 (8.0–8.5) μm in diameter, containing ovoid polar capsules 2.8 (2.5–3.4) × 2.6 (2.5–3.0) μm, and polar filament with 4–5 coils; and Sphaerospora hankai n.sp. from the renal tubules of the brown bullhead, Ictalurus nebulosus, with subspherical spores 6.1 (5.4–6.6) × 6.0 (5.4–6.5) μm, unequal subspherical polar capsules (larger, 2.8 (2.5–3.1) × 2.7 (2.3–2.9) μm; smaller, 2.4 (2.1–2.6) × 2.0 (1.9–2.2) μm), and polar filament with 4–5 coils in larger capsule, 3–4 coils in smaller capsule. Eimeria patersoni n.sp. is described from the kidney, spleen, and liver of L. gibbosus. Oocysts are subspherical (11.9 × 10.6), sporocysts ellipsoidal (10.4 (9.9–11.2) × 3.5 (2.6–4.0) μm), and sporozoites stubby (3.6 × 2.0 μm); sporocyst residuum has 1–3 large granules.

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