RESEARCH 

Project |01.1 Collective Behavior of Marine and Estuarine Fish

My research focuses on exploring the role of behavior in structuring nektonic communities and trophic interactions in marine and estuarine ecosystems at various spatial and temporal scales. I strive to fill gaps in our understanding of the fundamental processes that mediate predator-prey interactions, habitat use and aggregative tendencies of schooling organisms in dynamic estuarine environments. Specifically, I explore how schools (from forage fish to top-predators) form, maintain and collectively react as coordinated units to external factors such as predators, environmental conditions, anthropogenic disturbances, fishery activities and habitat structure. My approach to research is integrative and relies on laboratory, mesocosm and in situ behavioral experimentations, advanced acoustics (autonomous echosounders, high-resolution imaging sonars) and a suite of statistical, theoretical models and computational methods.

Project |02 How Physical and Environmental Variations affect Schooling Fish Behavior in Estuarine Ecosystems
In estuarine ecosystems, considerable variation in hydrodynamic properties exists within and across tidal cycles or even associated with periodic pulses of freshwater discharge (i.e. water control management strategies) and can have important impacts on structuring fish populations and communities. I explore how environmental factors (e.g., water turbidity, salinity, tide level, tannic vs. marine water) influence the behavior of aggregated fish  and the interactions of their predators in tidally-driven estuarine ecosystems. By integrating the detailed information from in situ optical and acoustic sensors, I investigate the properties of collective anti-predatory responses of schooling fish and how abiotic factors, habitat degradation and human disturbances are structuring pelagic nekton distributions and behavior in tidal estuarine habitats. These issues that are of particular interest for ecologists and natural resource managers.

Project |03 Exploring the Group Size Effect

Grouping is generally thought to improve animals' security through a combination of several anti-predatory mechanisms (the dilution of risk, a greater detection power of threats, collective defense or the confusion effect of predators). Security is also assumed to increase with the animals group size. I am investigating this group size effect in different taxa (fish, birds, ungulates and marsupials).

Just a sample of my work. To see more or discuss possible work >>

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However, A Lot of Questions Remain Unsolved...

 

1- Why do some animals exhibit this group size effect and some don't?

2- What is the functional interpretation of the group size effect?

3- Do all the individuals adjust their vigilance according to the size of their group in a same way?

4- What are the basis of these between-individual differences?

5- Does the group size effect framework suitable to explain large animal aggregations?

Project |04 Social Information Use 

Social animals can obtain information both by sampling the environment themselves and also by observing companions’ decisions. My aim is to determine the circumstances under which animals could use incorrect social information and consequently decide wrongly to adopt maladaptive behavior. I've started exploring the use of social information in  social birds during my PhD thesis in Prof. Luc-Alain Giraldeau's lab. A key results of my research is that, in some specific conditions, individuals disregard even reliable personal information and copy the erroneous behavior of others; a phenomenon that has been reported to be widespread in human societies.

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Project |01.2 Understanding the Formation of Massive Aggregation in Fish

 

I reexamine the classical models on prey group security for large aggregations of marine fish. I found little support from either empirical studies or classic models. I am reassessing the functional theory with predator-dependent models and consider other factors than predation to explain massive fish shoals. I am also taking into account the interplay between ultimate benefits and proximate perspectives is a key step in understanding large fish aggregations in marine ecosystems.

Project |01.3 Collective Information Transfer

Collective phenomena such as coordinated escape manoeuvres raise specific questions on how information spreads within a group despite the group size. My recent research demonstrates that large schools are able to make structural and behavioral adjustments in response to perceived predation risk in a way that improves collective information transfer, and thus responsiveness, during predator attacks. The results of my research show for the first time that schooling fish reduce their risk of capture by adopting a spatial organization that favors the speed and range of propagation of information about threat-related cues among school members. This research project combines laboratory and in situ experiments to examine i) the sensory basis of schooling behavior and ii) information flow in fish schools.

Project |06 Signal Design in Animal Communication 
 

Design characteristics of signals may have evolved to maximise signal efficiency. It is commonly assumed that constraints on signal design have usually shaped optimal display characteristics to improve signal transmission and information transfer of the signaller, and detection by intended receivers. 

 

In collaboration with Dr. Kevin Woo (SUNY Empire State College, NY), I am exploring how animals adjust and modify the structure of their communication signals to cope with changes in their environment.

 

 

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Project |07 Video Playback and 3D Animations 
 

I extensively use the video playback technique during my research. In several of my experimental projects this tool have been used to mimic social interactions in fish, birds and reptiles. The video playback technique appears as an efficient means to precisely control the behaviour of demonstrators. 

 

I am actively collaborating with Dr. Kevin Woo (Empire State College, NY) to further develop the video playback and computer-generated animation techniques to examine social interactions among species that are reliant on dynamic visual signals. 

 

 

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Project |05.1 Vigilance, Individual Differences and Anti-Predator Behavior

I am interested in understanding how gregariousness animals adjust their vigilance tactics in function of the size of their groups. Through several collaborations, I investigate how vigilance tactic differ according to the sex, reproductive status or personality of individuals. I explore the specific contributions of predator detection and risk dilution and the basis of individual differences in the use of vigilance tactics.I have published several scientific articles on this topic in different animal species as fish, ungulates, birds and marsupials.   

                                      

 

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Project |05.2 Vigilance, Information Transfer and Security in Animal Groups
 

 In addition, I am combining a theoretical approach and detailed information from behavioural observation (optical and acoustical) of collective reactions in schooling fish to explore how grouping may increase the survival of individuals through a rapid and efficient information transfer when some individuals have detected an approaching predator. 

                                      

 

 

In particular, we (Dr. Woo and I) are examining display characteristics in the Jacky dragon (Amphibolurus muricatus) and the efficiency of aggressive and submissive displays  across relative environmental noise. 

 

We are starting a new research project at the Prospect Park Zoo, Brooklin, NY, USA investigating the effect of urban noise disturbance on comminucation in captive Helmeted Guinea Fowl (Numida meleagris).

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© Guillaume Rieucau 2014 
 

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