Guillaume Rieucau

Louisiana Universities Marine Consortium

Aggregation in socially living fishes has evolved to improve safety from predators. The individual interaction mechanisms that govern collective behavior are determined by the sensory systems that translate environmental information into behavior. In dynamic environments, shifts in conditions impede effective visual sensory perception in fish schoo...

For many aquatic animals, distributional patterns, trophodynamic relationships, and reproductive activity are driven by complex biotic and abiotic ecosystem interactions that influence behaviour. Linking behavioural information to environmental stimuli and stressors can, therefore, help to anticipate population and ecosystem responses to changing c...

Acoustic signals play a crucial role in communication among animals, particularly in dolphins. Signature whistles, one of their most extensively studied vocalizations, enable dolphins to convey their identity to conspecifics through individually distinct whistle contours. However, it remains unclear whether rough-toothed dolphins (Steno bredanensis...

Coastal fish communities are under increasing levels of stress associated with climate variation and anthropogenic activities. However, the high degree of behavioral plasticity of many species within these communities allow them to cope with altered environmental conditions to some extent. Here, we combine meteorological information, data from hydr...

Assessments of individual animal health alerts to early signs of population level effects in wildlife but often rely on logistically complex wild animal captures, hindering our understanding of the wellbeing of populations in regions with limited resources. Here, we tested photogrammetry methods using small aerial drones for accurate morphometric m...

Estuarine ecosystem balance typically relies on strong food web interconnectedness dependent on a relatively low number of resident taxa, presenting a potential ecological vulnerability to extreme ecosystem disturbances. Following the Deepwater Horizon (DwH) oil spill disaster of the northern Gulf of Mexico (USA), numerous ecotoxicological studies...

Estuarine ecosystem balance typically relies on strong food web interconnectedness dependent on a relatively low number of resident taxa, presenting a potential ecological vulnerability to extreme ecosystem disturbances. Following the Deepwater Horizon (DwH) oil spill disaster of the northern Gulf of Mexico (USA), numerous ecotoxicological studies...

Lay abstract: Bottlenose dolphins display diverse feeding behaviors. Here, we report mud ring feeding behaviors by bottlenose dolphins in an estuary shared between Belize and Mexico. We detected four mud ring feeding events in boat- and aerial-based observations. In visual searches of Very High Resolution (VHR) satellite imagery, we detected mud ri...

Estuaries are dynamic environments where the safety of habitat refuges can be altered by a variety of natural and anthropogenic disturbances. After tropical storms or other high water run off events, water hyacinth (Eichhornia crassipes), an invasive floating freshwater plant, can enter estuarine habitats where it can colonize marsh edges and may i...

Assessing the body condition of wild animals is necessary to monitor the health of the population and is critical to defining a framework for conservation actions. Body condition indices (BCIs) are a non-invasive and relatively simple means to assess the health of individual animals, useful for addressing a wide variety of ecological, behavioral, a...

Animal groups are known to exhibit collective behaviours that allow for effective responses to predators and environmental factors. Habitats with high levels of structural complexity have been shown to influence the collective tendencies of these animal aggregations. However, the effect of anthropogenically induced habitat complexity on collective...

Stable isotope analysis (SIA) can be a powerful tool for investigating trophic ecology and energy fluxes through an ecosystem. In fishes, muscle tissue is generally preferred for SIA due to its intermediate turnover rate even though sampling muscle is often lethal. Here, we evaluated the feasibility of a fin clip model (FCM) using fin tissue as a n...

The Deepwater Horizon oil spill highlighted the need to understand the effects of oil exposure on marine eggs and larvae. To determine how short-duration exposure impacts the survivability of early life stages of the bay anchovy, Anchoa mitchilli, embryos and larvae ≤ 3-days-post-hatch (dph) were exposed to high-energy water accommodated fractions...

Behavioral interactions such as dominance are critical components of animal social lives, competitive abilities, and resulting distribution patterns with coexisting species. Strong interference competition can drive habitat separation, but less is known of the role of interference if agonistic interactions are weak. While most theoretical models as...

Oil spills threaten the structure and function of ecological communities. The Deepwater Horizon spill was predicted to have catastrophic consequences for nearshore fishes, but field studies indicate resilience in populations and communities. Previous research indicates many marsh fishes exhibit avoidance of oil contaminated areas, representing one...

Pattern formation and collective behaviour in animal aggregations is highly complex and occurs across many scales, over a wide range of environmental conditions. The patterns found in collective behaviour may be modulated by the environmental habitat in which a group is located. Here, we consider whether habitat context influences the collective be...

Oil spills threaten the structure and function of ecological communities. In the northern Gulf of Mexico, the 2010 Deepwater Horizon spill was among the largest marine disasters in history. While many predicted catastrophic consequences for nearshore fishes, field studies indicate surprising resilience in populations and communities. One potential...

Aquatic animals use and produce sound for critical life functions, including reproduction. Anthropogenic noise is recognized as a global source of environmental pollution and adequate conservation and management strategies are urgently needed. It becomes therefore critical to identify the reproductive traits that render a species vulnerable to acou...

Behavioral interactions such as dominance are critical components of animal social lives, competitive abilities, and resulting distribution patterns with coexisting species. Strong interference competition can drive habitat separation, but less is known of the role of interference if agonistic interactions are weak. While most theoretical models as...

In marine ecosystems, predator-prey interactions are known to structure critical processes (e.g., trophic transfer, nutrient regeneration) and have important implications for mediating community dynamics. However, the temporal and spatial scales over which these processes operate remain poorly understood mainly because the resolution provided by tr...

The use of unmanned aircraft systems (UASs), commonly referred to as drones, has rapidly expanded across many scientific disciplines. Like other fields, fisheries research would benefit significantly from broader use of this emerging technology but has lagged behind other disciplines. Like the implementation of satellite and aircraft‐based remote s...

A novel image analysis‐based technique applied to unmanned aerial vehicle (UAV) survey data is described to detect and locate individual free‐ranging sharks within aggregations. The method allows rapid collection of data and quantification of fine‐scale swimming and collective patterns of sharks. We demonstrate the usefulness of this technique in a...

The selectivity of fishing gears with respect to fish species and size is important, both for fisheries management and fishing operations. Purse seining is an efficient, environmentally friendly fish capture methodology generally targeting single species aggregations, but once a fish school has been selected and surrounded by the seine, there is no...

The fish mortalities during the experiment. (PDF)

Randomly chosen video sequence among responses scored as 3. (MP4)

R script to read the supporting data set for regenerating the tests and figures in the paper. (R)

The swimming speed as a function of time. (TIF)

Randomly chosen video sequence among responses scored as 0. (MP4)

Randomly chosen video sequence among responses scored as 1. (MP4)

Randomly chosen video sequence among responses scored as 2. (MP4)

Contains data to re-generate the tests and the figures in the paper. (CSV)

The present study tested whether the presence of already retained fishes inside baited fish pots acted as a social attraction and affected the entrance probability of Atlantic cod Gadus morhua in a fjord in northern Norway. Video analysis revealed that the probability of an entrance initially increased with the presence of low numbers of fishes ins...

Over the last decade, North Sea stocks of lesser sandeel (Ammodytes marinus), have undergone a dramatic decline caused by intensive local fishing pressure. Lesser sandeel is a key species of the North Sea supporting the largest fishery in this ecoregion. This species has developed the particular ability to burrow in sandy seabeds, while forming lar...

How animals interact collectively in groups is of interest for both ecologists and engineers, both from a mechanistic and functional point of view. A property of some large animal groups, regardless of their size, is their ability to perform highly coordinated anti-predatory reactions that can progress through entire groups. We developed a method u...

Rapid technical advances in the field of computer animation (CA) and virtual reality (VR) have opened new avenues in animal behavior research. Animated stimuli are powerful tools as they offer standardization, repeatability and complete control over the stimulus presented, thereby 'reducing' and 'replacing' the animals used, and 'refining' the expe...

To ensure efficient and sustainable purse-seine fisheries, the catch process must be monitored to better understand the reactions of fish to the gear. In this study, we monitored the behaviours of herring (Clupea harengus) and mackerel (Scomber scombrus) schools during purse-seine capture using a multibeam imaging sonar (Simrad MS70, 75–112 kHz) mo...

So far, actuated fish models have been used to study animal interactions in small-scale controlled experiments. This study, conducted in a semi-controlled setting, investigates robot⁵ interactions with a large wild-caught marine fish school (~3000 individuals) in their natural social environment. Two towed fish robots were used to decouple size, ta...

Many large-scale animal groups have the ability to react in a rapid and coordinated manner to environmental perturbations or predators. Information transfer among organisms during such events is thought to confer important antipredator advantages. However, it remains unknown whether individuals in large aggregations can change the structural proper...

Identifying perceptual thresholds is critical for understanding the mechanisms that underlie signal evolution. Using computer-animated stimuli, we examined visual speed sensitivity in the Jacky dragon Amphibolurus muricatus, a species that makes extensive use of rapid motor patterns in social communication. First, focal lizards were tested in discr...

In Southeast Alaska, overwintering Pacific herring (Clupea pallasii) form large conspicuous schools that are preyed upon by an abundance of mammalian and avian predators, thus leading to the question of why herring adopt a strategy that appears counterproductive to predator avoidance during these periods. We examined the spatial and temporal dynami...

We experimentally played back tones and sweeps to captive herring (Clupea harengus) in a net pen and measured the collective response of a large and a small group of fish using a camera, echo sounder, and multibeam sonar. The playbacks ranged in frequency from 160 to 500 Hz and 131 to 147 dB re 1 μPa in received sound pressure level. Herring behavi...

Schooling in fish is understood as a strategy reducing the risk of predation. Yet, it remains unsolved whether schooling fishes can change the structural properties of their collective in order to minimize risk and whether such adjustments promote efficient group-level responsiveness. We conducted a simulated-predator encounter experiment in a sea-...

Tidally-driven fluctuations lead to rapid variations in hydrological properties that can have profound effects on the dynamic and functions of salt marshes. During low tides, many nektonic species find refuge from predatory fish in shallow intertidal pools. The utilization of shallow pool refuges also exposes fishes to fitness costs that fluctuate...

Tidally driven fluctuations lead to rapid variations in hydrological properties that can have profound effects on the dynamic and functions of salt marshes. During low tides, many nektonic species find refuge from predatory fish in shallow intertidal pools. The utilization of shallow pool refuges also exposes fishes to fitness costs that fluctuate...

Visual signals that are designed for effective communication are complex. Over the years, researchers interested in the study of animal communication have employed various artificial stimuli during behavioral experiments to precisely control what the observers get to see or experience. These diverse techniques to stage animal interactions have offe...

It is well established that recognition of complex acoustic signals, such as bird song, is dependent upon the temporal ordering of signal units or syntax. Much less is known about functionally analogous visual displays. The jacky dragon (Amphibolurus muricatus) is a native Australian agamid lizard with a highly stereotyped visual display made up of...

Fish avoidance of vessels can bias fisheries-independent surveys. To understand these biases, recordings of underwater radiated vessel noise from a noise-reduced and a conventional research vessel were played back at the same sound pressure levels (SPL) as experienced in situ to Atlantic herring (Clupea harengus) in a net pen at two different densi...

An experimental study in a semi-controlled environment was conducted to examine whether school density in wild-caught Atlantic herring Clupea harengus affects the strength of their collective escape behaviours. Using acoustics, the anti-predator diving responses of C. harengus in two schools that differed in density were quantified by exposing them...

Avoiding predation is generally seen as the most common explanation for why animals aggregate. However, it remains questionable whether the existing theory provides a complete explanation of the functions of large shoals formation in marine fishes. Here, we consider how well the mechanisms commonly proposed to explain enhanced safety of group livin...

Aggregation is commonly thought to improve animals' security. Within aquatic ecosystems, group-living prey can learn about immediate threats using cues perceived directly from predators, or from collective behaviours, for example, by reacting to the escape behaviours of companions. Combining cues from different modalities may improve the accuracy o...

Despite variations of environmental noise, signals are designed to be effective and conspicuous over an appreciable distance. In particular, visual signals must be perceptible against interference caused by natural elements, such as windblown vegetation. We examined the efficiency of aggressive and submissive displays to elicit behavioural response...

Aggregation is thought to enhance an animal’s security through effective predator detection and the dilution of risk. A decline in individual vigilance as group size increases is commonly reported in the literature and called the group size effect. However, to date, most of the research has only been directed toward examining whether this effect oc...

Design characteristics of signals, such as their duration, may have evolved to maximize signal efficiency. It is commonly assumed that constraints on signal design have usually shaped the most optimal display characteristics to improve signal transmission and information transfer of the signaller, and detection by intended receivers. In this study,...

Parental food allocation decisions are based on information about nestling condition conveyed by begging signals. It is expected that parents should have evolved the ability to obtain detailed information about their nestlings' condition through multiple independent signals, thus allowing them to use optimal food allocation strategies depending on...

Traditionally, studies that explored animal communication have been directed towards the observation of natural interactions between individuals. Over the years, researchers have long championed the use of artificial stimuli in place of natural ones in behavioral experiments to precisely control what the observers get to see or experience. The empl...

We previously developed a model, based on the precepts of optimal patch use, to compare habitat quality both within and between environments. Here we illustrate the use of this model in a study estimating quality of winter habitats (deer yards) of white-tailed deer Odocoileus virginianus near the northern limit of their range by following their for...

Research on social learning has focused traditionally on whether animals possess the cognitive ability to learn novel motor patterns from tutors. More recently, social learning has included the use of others as sources of inadvertent social information. This type of social learning seems more taxonomically widespread and its use can more readily be...

When group size increases, animals from a wide range of taxa reduce vigilance and increase feeding rate, the so-called group size effect. This effect requires that group members display plastic behavioral responses both in terms of vigilance and foraging to obtain the security benefit from grouping and/or to cope with feeding competition. Most stud...

When animals forage socially, individuals can obtain prey from their own searching (producer tactic) or by using the behaviour of others (scrounger tactic) when it provides inadvertent social information (ISI) that food has been located. This ISI may either indicate the location of food (social information, SI), or it may indicate the quality of th...

Animals sample their surrounding environment to collect information, which can be obtained personally or by tracking the behavior of others (i.e., social information). Although social information appears to be generally advantageous, it can also be detrimental and may even conflict with personal information. We tested the effect that the strength o...

The use of video playbacks may provide a promising technique for the study of social behaviour because it allows experimenters to present a diverse set of behavioural patterns while precisely controlling what the observer experiences. However, in order to validate this technique for social foraging contexts, we must first show that video playbacks...

When foraging group sizes increase, animals generally decrease the time devoted to antipredator detection and increase their foraging rate, the commonly reported group size effect. The increased foraging rate is thought to follow from increased safety from predators because as group size increases, more eyes are available to detect predators and th...

The giving-up density of food (GUD), the amount of food remaining in a patch when a forager ceases foraging there, can be used to compare the costs of foraging in different food patches. But, to draw inferences from GUDs, specific effects of foraging costs (predation risk, metabolic and missed opportunities costs) on GUDs have to be identified. As...

The increasing use of the video playback technique in behavioural ecology reveals a growing need to ensure better control of the visual stimuli that focal animals experience. Technological advances now allow researchers to develop computer-generated animations instead of using video sequences of live-acting demonstrators. However, care must be take...

In gregarious animals, there is usually a negative relationship between individual vigilance and group size. This effect of group size is generally explained by increasing probability of predator detection (the many-eyes hypothesis) and by the dilution of risk occurring in larger groups. Few studies have attempted to examine the specific implicatio...

We developed an innovative method for estimating human impacts on animal species by measuring changes in feeding behaviour. We illustrate our approach with a study of the effect of vegetation control in a power-line right-of-way (ROW) passing through essential winter habitat of white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) at the no...

De nombreuses espèces animales vivent et s'alimentent en groupe, une situation qui requière que les animaux adoptent des réponses comportementales spécifiques à cette condition sociale. Les travaux effectués lors de mes études doctorales se sont principalement intéressés à explorer les effets que peuvent avoir le nombre de compagnons ainsi que leur...