Behavioural syndrome in juvenile eels and its ecological implications

Behaviour ◽  
2015 ◽  
Vol 152 (2) ◽  
pp. 147-166 ◽  
Author(s):  
Benjamin Geffroy ◽  
Bastien Sadoul ◽  
Agnès Bardonnet
Keyword(s):  
Life History ◽  
Anguilla Anguilla ◽  
Population Level ◽  
Behavioural Syndrome ◽  
European Eel ◽  
Diurnal Activity ◽  
Nocturnal Activity ◽  
Time Period ◽  
Ecological Implications ◽  
Long Time

Behavioural syndrome, which refers to a suite of correlated behaviours across differing situations, has been identified in numerous animals, including fish. The presence and conservation of a behavioural syndrome throughout evolutionary times suggests it confers various advantages at a population level. In eels, such as the European eel (Anguilla anguilla), activity and aggressiveness are important factors in their life history, since both traits influence dispersal and territoriality. In the present study we investigated whether these behavioural traits were consistent at both the nychtemeral scale (24 h) and over a long time period (7 months). In addition, we investigated if aggressiveness and activity were positively correlated. Both activity and aggressiveness were significantly repeatable, indicating that both behavioural traits could be considered as personality traits. Interestingly, nocturnal activity was correlated to diurnal activity, indicating that this personality trait was highly stable at the circadian scale. Both aggressiveness and activity were correlated in the course of the experiment, underlining the presence of a behavioural syndrome. The detection of two behaviourally distinct groups in juvenile eels: aggressive and active individuals versus their counterpart have implications in the understanding of the colonization profile of the watershed. We discuss these findings in relation to the ecology of this species.

scholarly journals Flow-wise or path-wise: diffusion in a fragmented dendritic network and implications for eels

2018 ◽  
Author(s):  
J. Domange ◽  
P. Lambert ◽  
L. Beaulaton ◽  
H. Drouineau
Keyword(s):  
Time Series ◽  
Anguilla Anguilla ◽  
River Networks ◽  
European Eel ◽  
River Catchment ◽  
Dendritic Network ◽  
Long Time ◽  
Colonization Process ◽  
River Fragmentation ◽  
River Catchments

AbstractThe European eel (Anguilla anguilla) is a catadromous species that reproduces at sea and inhabits continental waters during its growth phase. River fragmentation due to obstacles is considered one cause of the decline of this species. However, the colonization process of river catchments by eels is still poorly understood. In this article, we compare two scenarios for the diffusion of eels within river catchments: a path-wise scenario, in which movements are totally random, and a flow-wise scenario, in which movements are partially oriented. Based on these two scenarios, we attempted to predict the distribution of eels within dendritic river catchments, explicitly accounting for the presence of obstacles to movement. The model was fitted to a long-time series of electro-fishing data. The results suggest that the path-wise scenario is more predominant than the flow-wise scenario. Moreover, results show that the distribution of eels in river catchment depends on (i) the types of movements carried out by eels, (ii) the configuration of river networks and (iii) the positions of obstacles within catchments.

scholarly journals Long time frames to detect the impact of changing COVID-19 measures, Canada, March to July 2020

2021 ◽  
Vol 26 (40) ◽  
Author(s):  
Jessica E Stockdale ◽  
Renny Doig ◽  
Joosung Min ◽  
Nicola Mulberry ◽  
Liangliang Wang ◽  
...  
Keyword(s):  
Population Level ◽  
Time Frame ◽  
Control Measures ◽  
Type Model ◽  
Time Period ◽  
Long Time ◽  
The Mean ◽  
Reported Data ◽  
Time Frames ◽  
The Impact

Background Many countries have implemented population-wide interventions to control COVID-19, with varying extent and success. Many jurisdictions have moved to relax measures, while others have intensified efforts to reduce transmission. Aim We aimed to determine the time frame between a population-level change in COVID-19 measures and its impact on the number of cases. Methods We examined how long it takes for there to be a substantial difference between the number of cases that occur following a change in COVID-19 physical distancing measures and those that would have occurred at baseline. We then examined how long it takes to observe this difference, given delays and noise in reported cases. We used a susceptible-exposed-infectious-removed (SEIR)-type model and publicly available data from British Columbia, Canada, collected between March and July 2020. Results It takes 10 days or more before we expect a substantial difference in the number of cases following a change in COVID-19 control measures, but 20–26 days to detect the impact of the change in reported data. The time frames are longer for smaller changes in control measures and are impacted by testing and reporting processes, with delays reaching ≥ 30 days. Conclusion The time until a change in control measures has an observed impact is longer than the mean incubation period of COVID-19 and the commonly used 14-day time period. Policymakers and practitioners should consider this when assessing the impact of policy changes. Rapid, consistent and real-time COVID-19 surveillance is important to minimise these time frames.

scholarly journals Fecundity of silver-phase eels (Anguilla anguilla) from different habitat types and geographic locations

2015 ◽  
Vol 73 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Ruairí MacNamara ◽  
T. Kieran McCarthy ◽  
Håkan Wickström ◽  
Patrik D. Clevestam
Keyword(s):  
Life History ◽  
Body Size ◽  
Baltic Sea ◽  
Life History Traits ◽  
Geographic Origin ◽  
Habitat Type ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Habitat Types ◽  
Geographic Locations

Abstract The reproductive ecology of European eel (Anguilla anguilla) is poorly understood, though information on life-history traits such as fecundity is necessary for appropriate management of this critically endangered species. During the growth period of the life cycle, yellow-phase eels can be resident in different habitat types (e.g. salinity ranging from freshwater to marine) over a wide geographic distribution. Consequently, maturing silver-phase eels migrating back to the oceanic spawning grounds can display considerable variation in certain life-history traits depending on their habitat and/or geographic origin. Few fecundity estimates are available from wild A. anguilla, and no investigation of the effects of habitat type (i.e. salinity) or geographic location on variation in fecundity has been undertaken. To assess the former, we examined silver-phase eels which had predominantly been resident in freshwater (Lake Mälaren, Sweden) or brackish (Baltic Sea) habitats. Despite Lake Mälaren eels generally being larger, there was no difference in the fecundity–body size relationship between these salinity zones. Second, we determined if fecundity differed between silver-phase eels sampled from different geographic locations: Lake Mälaren and the Baltic Sea outlet in Sweden, the River Shannon in Ireland (northwest Europe) and Vistonis Lake in Greece (eastern Mediterranean). Our results showed that silver-phase eels from Sweden (Lake Mälaren and Baltic Sea outlet) and Greece were significantly more fecund at a given body size than those from Ireland. Spawner models and conservation policies should therefore take account of eel geographic origin in particular when incorporating this life-history parameter.

scholarly journals Long time frames to detect the impact of changing COVID-19 control measures

2020 ◽  
Author(s):  
Jessica E Stockdale ◽  
Renny Doig ◽  
Joosung Min ◽  
Nicola Mulberry ◽  
Liangliang Wang ◽  
...  
Keyword(s):  
Population Level ◽  
Time Frame ◽  
Control Measures ◽  
Policy Makers ◽  
Time Period ◽  
Reporting Process ◽  
Long Time ◽  
The Mean ◽  
Time Frames ◽  
The Impact

AbstractBackgroundMany countries have implemented population-wide interventions such as physical distancing measures, in efforts to control COVID-19. The extent and success of such measures has varied. Many jurisdictions with declines in reported COVID-19 cases are moving to relax measures, while others are continuing to intensify efforts to reduce transmission.AimWe aim to determine the time frame between a change in COVID-19 measures at the population level and the observable impact of such a change on cases.MethodsWe examine how long it takes for there to be a substantial difference between the cases that occur following a change in control measures and those that would have occurred at baseline. We then examine how long it takes to detect a difference, given delays and noise in reported cases. We use changes in population-level (e.g., distancing) control measures informed by data and estimates from British Columbia, Canada.ResultsWe find that the time frames are long: it takes three weeks or more before we might expect a substantial difference in cases given a change in population-level COVID-19 control, and it takes slightly longer to detect the impacts of the change. The time frames are shorter (11-15 days) for dramatic changes in control, and they are impacted by noise and delays in the testing and reporting process, with delays reaching up to 25-40 days.ConclusionThe time until a change in broad control measures has an observed impact is longer than is typically understood, and is longer than the mean incubation period (time between exposure than onset) and the often used 14 day time period. Policy makers and public health planners should consider this when assessing the impact of policy change, and efforts should be made to develop rapid, consistent real-time COVID-19 surveillance.

scholarly journals Cause or consequence? Exploring the role of phenotypic plasticity and genetic polymorphism in the emergence of phenotypic spatial patterns of the European eel

2017 ◽  
Vol 74 (7) ◽  
pp. 987-999 ◽  
Author(s):  
Maria Mateo ◽  
Patrick Lambert ◽  
Stéphane Tetard ◽  
Martin Castonguay ◽  
Bruno Ernande ◽  
...  
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Habitat Selection ◽  
Life History Traits ◽  
Environmental Variability ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Anthropogenic Pressures ◽  
The Impact

The European eel (Anguilla anguilla), and generally, temperate eels, are relevant species for studying adaptive mechanisms to environmental variability because of their large distribution areas and their limited capacity of local adaptation. In this context, GenEveel, an individual-based optimization model, was developed to explore the role of adaptive phenotypic plasticity and genetic-dependent habitat selection, in the emergence of observed spatial life-history traits patterns for eels. Results suggest that an interaction of genetically and environmentally controlled growth may be the basis for genotype-dependent habitat selection, whereas plasticity plays a role in changes in life-history traits and demographic attributes. Therefore, this suggests that those mechanisms are responses to address environmental heterogeneity. Moreover, this brings new elements to explain the different life strategies of males and females. A sensitivity analysis showed that the parameters associated with the optimization of fitness and growth genotype were crucial in reproducing the spatial life-history patterns. Finally, it raises the question of the impact of anthropogenic pressures that can cause direct mortalities but also modify demographic traits and act as a selection pressure.

scholarly journals Population-, sex- and individual level divergence in life-history and activity patterns in an annual killifish

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7177 ◽  
Author(s):  
Eli S.J. Thoré ◽  
Arnout F. Grégoir ◽  
Bart Adriaenssens ◽  
Charlotte Philippe ◽  
Robby Stoks ◽  
...  
Keyword(s):  
Life History ◽  
Population Level ◽  
Activity Level ◽  
Life History Strategies ◽  
Diurnal Activity ◽  
Activity Change ◽  
Biological Organization ◽  
Trade Offs ◽  
The Individual ◽  
Different Levels

Variation in life-history strategies along a slow-fast continuum is largely governed by life-history trade-offs. The pace-of-life syndrome hypothesis (POLS) expands on this idea and suggests coevolution of these traits with personality and physiology at different levels of biological organization. However, it remains unclear to what extent covariation at different levels aligns and if also behavioral patterns such as diurnal activity changes should be incorporated. Here, we investigate variation in life-history traits as well as behavioral variation at the individual, sex and population level in the Turquoise killifish Nothobranchius furzeri. We performed a common garden laboratory experiment with four populations that differ in pond permanence and scored life-history and behavioral (co-) variation at the individual and population level for both males and females. In addition, we focused on diurnal activity change as a behavioral trait that remains understudied in ecology. Our results demonstrate sex-specific variation in adult body size and diurnal activity change among populations that originate from ponds with differences in permanence. However, there was no pond permanence-dependent divergence in maturation time, juvenile growth rate, fecundity and average activity level. With regard to behavior, individuals differed consistently in locomotor activity and diurnal activity change while, in contrast with POLS predictions, we found no indications for life-history and behavioral covariation at any level. Overall, this study illustrates that diurnal activity change differs consistently between individuals, sexes and populations although this variation does not appear to match POLS predictions.

Effects of feed composition on life history developments in feed intake, metabolism, growth and body composition of European eel, Anguilla anguilla

Aquaculture ◽  
2007 ◽  
Vol 267 (1-4) ◽  
pp. 175-187 ◽  
Author(s):  
Leon T.N. Heinsbroek ◽  
Paul L.A. Van Hooff ◽  
William Swinkels ◽  
Michel W.T. Tanck ◽  
Johan W. Schrama ◽  
...  
Keyword(s):  
Body Composition ◽  
Life History ◽  
Feed Intake ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Feed Composition
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