scholarly journals Planktivore vertical migration and shoaling under a subarctic light regime

2009 ◽  
Vol 66 (4) ◽  
pp. 525-539 ◽  
Author(s):  
Karl Øystein Gjelland ◽  
Thomas Bøhn ◽  
John K. Horne ◽  
Ingrid Jensvoll ◽  
Frank Reier Knudsen ◽  
...  
Keyword(s):  
Predation Risk ◽  
Vertical Migration ◽  
Light Regime ◽  
Planktivorous Fish ◽  
Day Length ◽  
Coregonus Lavaretus ◽  
Trade Off ◽  
Light Levels ◽  
State Dependent ◽  
Daytime Behaviour

Visually foraging planktivorous fish are prey of visual predators, and their foraging behaviour may be affected by light levels both in terms of gain and risk. The large seasonal change in day length throughout a subarctic summer at 69°N was used to show the influence of light on diel vertical migration (DVM) and shoaling patterns in a planktivorous fish assemblage consisting of two species ( Coregonus lavaretus and Coregonus albula ). Under the midnight sun in June, night and daytime behaviour was similar, with extensive shoaling and limited DVM. With increasingly darker nights towards autumn, the fish dispersed during the dark hours and showed more extensive DVM. Throughout the changing light regime of both the day and the season, the planktivores consistently chose depths with light levels compatible with visual foraging and reduced predation risk as revealed from reactive distance modelling of coregonids and their salmonid predators. The findings support the hypothesis that behavioural decisions are based on a trade-off between foraging rate and predation risk, and increased predator avoidance behaviour towards autumn suggests that this trade-off is state-dependent.

Diel vertical migration in the Lake Superior pelagic community. I. Changes in vertical migration of coregonids in response to varying predation risk

2006 ◽  
Vol 63 (10) ◽  
pp. 2286-2295 ◽  
Author(s):  
Thomas R Hrabik ◽  
Olaf P Jensen ◽  
Steven J.D. Martell ◽  
Carl J Walters ◽  
James F Kitchell
Keyword(s):  
Predation Risk ◽  
Vertical Migration ◽  
Lake Superior ◽  
Light Levels ◽  
Biological Variables ◽  
Physico Chemical ◽  
Prey Resources ◽  
Diel Variability ◽  
The Vertical Distribution ◽  
Changing Light

The distribution of fishes is influenced by a host of physico-chemical and biological variables, including temperature and oxygen, prey abundance, feeding or assimilation rates, and predation risk. We used hydroacoustics and midwater trawls to measure the vertical distribution of pelagic fishes during a series of research cruises on Lake Superior's western arm in 2001 and 2004. Our objective was to assess vertical structuring in the fish assemblage over varying light levels. We observed variability in vertical structuring of both ciscoes (Coregonus spp.) and their primary predator, the siscowet (Salvelinus namaycush siscowet). Our results indicate that deepwater predators and prey migrate extensively over a diel cycle. This migration pattern is most consistent with changes in the distribution of prey resources for siscowet and diel variability in predation risk controlled by changing light levels for ciscoes. The magnitude of vertical migration in ciscoes increased with higher abundance of siscowets, supporting predation risk as a driver of cisco distribution. This study describes the extent of vertical migration in each group of fish, provides a statistical description of the pattern, and discusses the implications for trophic interactions in the Lake Superior food web.

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

scholarly journals On Uncertainty Relations and Entanglement Detection with Mutually Unbiased Measurements

2015 ◽  
Vol 22 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Alexey E. Rastegin
Keyword(s):  
The State ◽  
Uncertainty Relations ◽  
Trade Off ◽  
Entropic Uncertainty Relations ◽  
Finite Dimensional ◽  
State Dependent ◽  
Entanglement Detection

We formulate some properties of a set of several mutually unbiased measurements. These properties are used for deriving entropic uncertainty relations. Applications of mutually unbiased measurements in entanglement detection are also revisited. First, we estimate from above the sum of the indices of coincidence for several mutually unbiased measurements. Further, we derive entropic uncertainty relations in terms of the Rényi and Tsallis entropies. Both the state-dependent and state-independent formulations are obtained. Using the two sets of local mutually unbiased measurements, a method of entanglement detection in bipartite finite-dimensional systems may be realized. A certain trade-off between a sensitivity of the scheme and its experimental complexity is discussed.

Diel vertical migration of adult burbot: a dynamic trade-off among feeding opportunity, predation avoidance, and bioenergetic gain

2013 ◽  
Vol 70 (12) ◽  
pp. 1765-1774 ◽  
Author(s):  
P.M. Harrison ◽  
L.F.G. Gutowsky ◽  
E.G. Martins ◽  
D.A. Patterson ◽  
A. Leake ◽  
...  
Keyword(s):  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Depth Distribution ◽  
Benthic Species ◽  
Migration Strategy ◽  
Trade Off ◽  
Vertical Activity ◽  
Benthic Fishes ◽  
Diel Period ◽  
Migration Probability

Diel vertical migration (DVM) of pelagic organisms is typically attributed to bioenergetic gain, foraging opportunity, predator avoidance, and multifactor hypotheses. While a number of benthic species perform nightly migrations into shallower waters, the function of these DVMs has largely been ignored in benthic fishes. We used depth and temperature sensing telemetry to investigate DVM function in burbot (Lota lota), a freshwater benthic piscivore. We modeled the influence of season, diel period, and body size on the depth, vertical activity, migration probability, and thermal experience of 47 adult burbot over 2 years in a reservoir in British Columbia, Canada. Burbot were found to occupy significantly shallower water at night than during the day. Our results, which showed elevated nightly activity and a seasonal size-structured depth distribution during DVMs, suggest these migrations likely provide a feeding opportunity “window” for this nocturnal predator, constrained by predation or cannibalism threats to smaller individuals. The observed thermal experience patterns suggest DVM may also provide a seasonal bioenergetic advantage. Our detection of within-individual plasticity in migration strategy is indicative of a partial migration. Taken together, our results suggest a multifactor DVM hypothesis: a dynamic trade-off among bioenergetic advantage, foraging opportunity, and predation threat.

A Comparison of Dynamic-State-Dependent Models of the Trade-Off Between Growth, Damage, and Reproduction

2011 ◽  
Vol 178 (6) ◽  
pp. 774-786 ◽  
Author(s):  
Who-Seung Lee ◽  
Neil B. Metcalfe ◽  
Pat Monaghan ◽  
Marc Mangel
Keyword(s):  
Dynamic State ◽  
Trade Off ◽  
State Dependent

PHYSIOLOGICAL AND BEHAVIORAL RESPONSES TO PREDATORS SHAPE THE GROWTH/PREDATION RISK TRADE-OFF IN DAMSELFLIES

Ecology ◽  
2001 ◽  
Vol 82 (6) ◽  
pp. 1535-1545 ◽  
Author(s):  
Mark A. McPeek ◽  
Margaret Grace ◽  
Jean M. L. Richardson
Keyword(s):  
Predation Risk ◽  
Behavioral Responses ◽  
Trade Off

Games Embedded in Life

2020 ◽  
pp. 203-230
Author(s):  
John M. McNamara ◽  
Olof Leimar
Keyword(s):  
Reproductive Success ◽  
Dynamic Games ◽  
Traditional Approach ◽  
Holistic Approach ◽  
Current Situation ◽  
Lifetime Reproductive Success ◽  
Trade Off ◽  
State Dependent ◽  
Mean Lifetime ◽  
Payoff Structure

Many games focus on a part of the life of an organism. The payoff structure of the game then represents how the game affects fitness proxies such as mean lifetime reproductive success, which are concerned with the whole of the life of the organism. However, the traditional approach of specifying payoffs in advance of the analysis of the game can lead to inconsistencies because the rest of the life of an individual is not fixed but depends on what happens in the game. This chapter concerns this issue, identifying situations in which a more holistic approach is needed. A series of models illustrates links between the current situation and a lifetime perspective. When each of two parents must decide whether to care for their common young or desert, the payoff for desertion depends on the solution of the game and cannot be specified in advance. A game in which two males contest for a female illustrates the approach that must be taken if this game can be repeated at a later time. A game in which individuals must possess territories in order to breed is developed that highlights various interdependencies and, by incorporating learning, advances the understanding of owner–intruder interactions. The interdependencies in state-dependent dynamic games are also illustrated with a model in which individuals must trade off the risks of starvation and predation in a situation in which the choice of the best foraging habitat depends on the number of other animals that use that habitat.

Ecological drivers of group size in female Alpine chamois, Rupicapra rupicapra

Mammalia ◽  
2015 ◽  
Vol 79 (4) ◽  
Author(s):  
Roberta Chirichella ◽  
Andrea Mustoni ◽  
Marco Apollonio
Keyword(s):  
Predation Risk ◽  
Energy Intake ◽  
Group Size ◽  
Food Availability ◽  
Herd Size ◽  
Rupicapra Rupicapra ◽  
Trade Off ◽  
Mammalian Herbivores ◽  
Alpine Chamois

AbstractIn large mammalian herbivores, an increase in herd size not only reduces predation risk but also energy intake. As a consequence, the size of the groups made up by herbivores is often assumed to be the outcome of a trade-off depending on local predation risk and food availability. We studied Alpine chamois (

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