Diel onshore–offshore migrations in northern redbelly dace, Phoxinus eos (Cope), in relation to prey distribution in a small oligotrophic lake

1988 ◽  
Vol 66 (6) ◽  
pp. 1249-1253 ◽  
Author(s):  
Marc Naud ◽  
Pierre Magnan
Keyword(s):  
Littoral Zone ◽  
Salvelinus Fontinalis ◽  
Oligotrophic Lake ◽  
Pelagic Zone ◽  
Brook Charr ◽  
Significant Preference ◽  
Prey Distribution ◽  
Feeding Efficiency ◽  
Risk Of Predation ◽  
Increased Risk

Northern redbelly dace, Phoxinus eos (Cope), exhibit diel onshore–offshore migrations in a small oligotrophic Quebec lake. The fish swim in shoals in the littoral zone during the day, migrate to the pelagic zone at sunset, where the shoals break up into single fish, and then go back to the littoral zone at sunrise. Dace eat mainly two cladocerans, Daphnia and Holopedium. Zooplankton sampling indicated that Daphnia were significantly more abundant in the pelagic zone than in the littoral zone, and Holopedium were rarely found in the littoral zone. Dace showed a significant preference for a dense cover habitat over a sparse cover habitat in the littoral zone during the day. Our results support the hypothesis that dace migrate to the pelagic zone at sunset to increase their feeding efficiency on zooplankton. The foraging benefits of remaining in the offshore zone may be offset by increased risk of predation by brook charr, Salvelinus fontinalis (Mitchill), during the daylight hours, thus resulting in diel onshore–offshore migrations.

The energetic implications of the diel onshore-offshore migration by dace(Phoxinus eos x P. neogaeus) in a small oligotrophic lake

1997 ◽  
Vol 54 (9) ◽  
pp. 1996-2006 ◽  
Author(s):  
S Gauthier ◽  
D Boisclair
Keyword(s):  
Littoral Zone ◽  
Oligotrophic Lake ◽  
Pelagic Zone ◽  
Lepomis Gibbosus ◽  
Daily Ration ◽  
Average Growth ◽  
Mass Growth ◽  
Pumpkinseed Sunfish ◽  
Consumption Rates

We assessed the energetic implications of onshore-offshore migrations executed by dace (Phoxinus eos times P. neogaeus). We estimated growth, consumption, and activity rates for dace allowed to migrate and for dace restricted to the littoral zone during 45 days. We also estimated the growth and consumption rates of a permanent littoral resident, the pumpkinseed sunfish (Lepomis gibbosus) kept with migrating dace and compared these values with those obtained for sunfish kept with dace restricted to the littoral zone. Dace migrated from the littoral towards the pelagic zone at dusk and returned to the littoral zone at dawn. On average, 70% of the daily ration of dace was obtained during the migration. Consumption and activity rates of dace that executed diel migrations were twice those estimated for dace restricted to the littoral zone. Average growth of dace allowed to migrate was 0.38 g wet mass, but fish resticted to the littoral lost 0.36 g wet mass. Growth and consumption rates of sunfish were not affected by the confinement of dace in the littoral zone. The survival of dace in the presence of a littoral competitor and a pelagic predator appears closely linked to the energetic advantages associated to diel onshore-offshore migrations.

Individual Variation in Foraging Movements in a Lake Population of Young-of-the-Year Brook Charr (Salvelinus Fontinalis)

Behaviour ◽  
1995 ◽  
Vol 132 (1-2) ◽  
pp. 57-74 ◽  
Author(s):  
Mark S. Ridgway ◽  
Peter A. Biro
Keyword(s):  
Environmental Factors ◽  
Littoral Zone ◽  
Salvelinus Fontinalis ◽  
Ingestion Rate ◽  
Brook Charr ◽  
Near Shore ◽  
General Variation ◽  
Young Of The Year ◽  
Pattern Of Variation ◽  
Foraging Movements

AbstractWe examined the variation in foraging movements in a population of young-of-the-year (YOY) brook charr living in the near-shore littoral zone of a lake. By repeating the methodology of an earlier stream study, we made direct comparisons between data from lake and stream populations. In general, the pattern of variation in foraging movements was similar between the two sites with greater variability and activity observed in the lake population. The dichotomous nature of the proportion of time spent moving in the stream was also observed in the lake population but in a reversal of the stream pattern. Charr that moved constantly while foraging represented the largest movement category in the lake. In general, variation in foraging movements were more strongly related to the rate of prey rejection, whereas environmental factors, such as distance from shore, submerged objects, and the amount of overhead riparian cover, were more strongly related to prey ingestion. This last finding directly contrasts with that found in the stream literature for YOY charr in still water where ingestion rate, as estimated using feeding attempt rate, increases with the mobility of YOY charr.

BEHAVIOURAL RESPONSES TO CONSPECIFIC DISTURBANCE CHEMICALS ENHANCE SURVIVAL OF JUVENILE BROOK CHARR, SALVELINUS FONTINALIS, DURING ENCOUNTERS WITH PREDATORS

Behaviour ◽  
2002 ◽  
Vol 139 (9) ◽  
pp. 1099-1109 ◽  
Author(s):  
Reehan Mirza ◽  
Douglas Chivers
Keyword(s):  
Survival Benefit ◽  
Chemical Cues ◽  
Salvelinus Fontinalis ◽  
Aquatic Organisms ◽  
Northern Pike ◽  
Antipredator Behaviour ◽  
Brook Charr ◽  
Risk Of Predation ◽  
Chemical Stimuli ◽  
Disturbance Cues

AbstractSeveral species of aquatic organisms release chemical cues upon detecting predators. These chemicals may serve to 'warn' nearby conspecifics of the predator and hence have been termed disturbance cues. Disturbance cues are thought to be low-level indicators of risk to which prey animals respond with antipredator behaviour. However, little is known about the distribution of disturbance cues among different taxa or how prey animals use these cues to mediate their risk of predation. In this study we exposed brook charr (Salvelinus fontinalis) to water from a tank containing cues of disturbed or undisturbed conspecifics at the same time as we exposed them to cues of an unknown predator, northern pike (Esox lucius). In subsequent trials, we staged encounters between the charr and a pike and tested for differences in survival. We found that charr that were exposed to simultaneous cues from disturbed conspecifics and pike odour subsequently avoided the pike significantly more than charr that had been previously exposed to chemical stimuli from undisturbed charr plus pike odour. Moreover, pike took significantly longer to capture charr that had been previously exposed to disturbance cues from conspecifics plus pike stimuli compared to charr previously exposed to cues from undisturbed charr plus pike stimuli. Ours is the first study to demonstrate that detection of disturbance cues can provide a survival benefit during an encounter with a predator.

The population dynamics of bite-sized predators: prey dependence, territoriality, and mobility

2018 ◽  
Author(s):  
Xavier Lambin
Keyword(s):  
Prey Species ◽  
Top Down ◽  
Predator Prey ◽  
Biological Barrier ◽  
Reciprocal Interactions ◽  
Demographic Rates ◽  
Risk Of Predation ◽  
Increased Risk ◽  
Rodent Prey ◽  
Small Mustelids

The dependency of mustelid demographic rates on prey abundance has the potential to cause a strong coupling between predator-prey populations. Data on mustelid dynamics show that such strong reciprocal interactions only materialise in some restricted conditions. Bite-size mustelid predators searching for scarce, depleted prey expose themselves to increased risk of predation by larger predators of small mammal that are themselves searching for similar prey species. As voles or muskrats become scarcer, weasels and mink searching for prey over larger areas become increasingly exposed to intra-guild predation, unless they operate in a habitat refuge such as the sub-nivean space. Where larger predators are sufficiently abundant or exert year-round predation pressure on small mustelids, their impact on mustelids may impose biological barrier to dispersal that are sufficient to weaken the coupling between small mustelids and their rodent prey, and thus impose a degree of top down limitation on mustelids.

Bénéfices à court terme des mouvements anadromes saisonniers pour une population d'omble de fontaine (Salvelinus fontinalis) du Nouveau Québec

1991 ◽  
Vol 48 (11) ◽  
pp. 2212-2222 ◽  
Author(s):  
Jean-François Doyon ◽  
Christiane Hudon ◽  
Roderick Morin ◽  
F. G. Whoriskey Jr.
Keyword(s):  
Water Level ◽  
Egg Size ◽  
Salvelinus Fontinalis ◽  
Condition Factor ◽  
Size At Maturity ◽  
Brook Charr ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Single Population ◽  
Energetic Reserves

This study characterizes the seasonal anadromous movements of a brook charr population and compares its biological and energetic characteristics with charr spending summer in freshwaters. Downstream movements monitored at a counting fence over 3 yr were most intense in spring but occurred until fall and were positively correlated with rapid increases of water level. The timing of movements varied from year to year. Smaller charr were most subject to being swept downstream compared with freshwater residents, and most trout were concentrated near the mouth of the river. These patterns suggest that the downstream movements of charr in this system are passive. Upstream migrants had a higher condition factor and a lower tissue water content than freshwater residents, indicating that downstream movements result in a faster accumulation of energetic reserves during summer. However, the fortuitous character of anadromous migrations as well as the absence of differences in the biological characteristics (growth, size at maturity, fecundity, egg size) suggests that anadromous and resident fish belong to a single population whose yearly migrant component could be randomly determined.

The effects of moonlight on nocturnal activity in bushy-tailed wood rats (Neotoma cinerea)

1999 ◽  
Vol 77 (3) ◽  
pp. 480-485 ◽  
Author(s):  
Michael G Topping ◽  
John S Millar ◽  
James A Goddard
Keyword(s):  
Light Level ◽  
Intermediate Level ◽  
Nocturnal Activity ◽  
Risk Of Predation ◽  
Increased Risk ◽  
Neotoma Cinerea ◽  
Two Measures ◽  
Males And Females ◽  
Rocky Outcrops ◽  
Breeding Seasons

The nocturnal activity of bushy-tailed wood rats (Neotoma cinerea) was monitored for two breeding seasons (1993 and 1994) in the Canadian Rockies. Radiotelemetry was used under three levels of moonlight to assess two measures of nocturnal activity: (i) the proportion of animals crossing rocky outcrops and entering the surrounding forest to forage, search for mates, or both, and (ii) the distance moved from the den site while in the forest. Males and females exhibited significant differences among moonlight levels, with greater activity on nights of intermediate-level moonlight and less activity on nights with bright or dark moonlight. There was no difference in the proportions of males and females active at any moonlight level. The distances moved from the den did not differ among moonlight levels for either males or females. Having traversed the rocks and entered the forest, individuals moved similar distances regardless of light level. These results suggest that wood rats respond to moonlight only when making the decision to cross rocks and enter the forest. This behaviour presumably serves to counteract the increased risk of predation on bright nights.

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.

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