Just a sample of my work. To see more or discuss possible work >>
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 |01.1 Fish Collective Behavior
My research focuses on exploring the role of behavior in structuring nektonic communities and trophic interactions in marine, estuarine and fresh water 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 |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 |02 How Physical and Environmental Variations affect Schooling Fish Behavior
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 Imaging Sonar: An Eye Below the Surface
Acquiring reliable quantitative measurements about swimming dynamic and behavior in situ remains a challenging task. I utilize non-intrusive high-resolution imaging sonar to collect behavioral data of free-ranging animals with no disturbance and irrespective of light level or turbidity. I have been successful in applying Particle Image Velocimetry to process acoustic videos in order to measure swimming dynamics of massive schools of pelagic fish, or shark and cownose ray aggregations. This approach has been instrumental in the examination of the formation, dynamics, and structural variations of massive shoals and provides valuable information for conservation and management plans. Under a recently BOEM-funded research project, I conduct imaging sonar surveys to explore habitat use and foraging ecology of cownose rays and other large nektonic species in offshore sand excavation sites of the northern Gulf of Mexico.
Project |04 Social, Spatial and Foraging Behaviors of Marine Megafauna
Using UAVs (drones), I observe free-ranging large group-living epipelagic animals (e.g., sharks, dolphins and manatees) and quantify their movements and behavior. UAV equipped with a high-resolution video camera are used to provide density estimates of marine megafauna with no or limited disturbance. Multi-target computer tracking and video analysis algorithms developed in my lab are used to quantify dynamic collective behaviors. My efforts are now directed towards the implementation of automated video post-processing and machine learning techniques.
Project |05.1 Marine mammal health conditions
Evaluating the body condition of wild animals is critical to assess the health of at-risk populations. Using drone-based photogrammetry, I am involved in the development of body condition indices (BCIs) to assess the health of populations of Antillean and Floridian manatees to alert to early signs of population level effects. Specifically, the use of BCIs has allows to reveal the existence of distinct ecotypes in Antillean manatees and evaluates health condition of overwintering Floridian manatees during an unexpected mortality event.
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).
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.
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.