Lateral Line System Of Fish Research Articles

Butyl Benzyl Phthalate (BBP) disrupts neuromast development in embryonic zebrafish

Butyl benzyl phthalate (BBP) is found in common household and industrial products world-wide. Phthalates are not covalently bound to plastics and continuously leach into the soil, sediment and aquatic environments. The lateral line system of fish is a mechanosensory system composed of neuromasts essential for survival behaviors including rheotaxis, schooling and predator avoidance. Here, we investigated the developmental toxicity of BBP on the developing lateral line neuromasts in zebrafish. Embryos were treated at gastrula stage with BBP and analyzed by DASPEI staining at 4 days post fertilization. We find that BBP negatively affects neuromast development leading to loss of DASPEI signal in neuromasts in a concentration dependent manner.

Research on the torpedo-shaped biomimetic MEMS vector wake detector

Autonomous Underwater Vehicles (AUVs) are a technological safeguard for executing marine tasks. However, traditional acoustic and optical technologies may fail to provide AUVs with precise near-field perception in complex, turbid environments. Inspired by the lateral line system of fish, a biomimetic MEMS vector wake detector is proposed. Based on the differential pressure sensing mechanism of the canal neuromasts, finite element software is utilized to optimize the shape and resistance performance of the detector's packaging structure. The geometric parameters are determined, and the integration and fabrication of the sensor are performed. The characterization results demonstrate that the detector's sensitivity is 1678 mV/(m/s), with a non-linear error of 3.73 % linearity and a detection threshold of 0.2 m/s. The angle and direction test results verify it possesses vector detection capability and can discern the wake direction. This wake detector could provide a valuable method of cluster perception for underwater vehicles.

Reconstructing the pressure field around swimming fish using a physics-informed neural network.

Fish detect predators, flow conditions, environments, and each other through pressure signals. Lateral line ablation is often performed to understand the role of pressure sensing. In this study, the authors propose a non-invasive method for reconstructing the instantaneous pressure field sensed by a fish's lateral line system from 2D particle image velocimetry (PIV) measurements. The method uses a physics-informed neural network (PINN) to predict an optimized solution for the pressure field near and on the fish's body that satisfy both the Navier-Stokes equations and the constraints put forward by the PIV measurements. The method was validated using a direct numerical simulation of a swimming mackerel, Scomber scombrus, and was applied to experimental data of a turning zebrafish, Danio rerio. The results demonstrate that this method is relatively insensitive to the spatio-temporal resolution of the PIV measurements and accurately reconstructs the pressure on the fish's body.

Lateral line morphology, sensory perception and collective behaviour in African cichlid fish.

The lateral line system of fishes provides cues for collective behaviour, such as shoaling, but it remains unclear how anatomical lateral line variation leads to behavioural differences among species. Here we studied associations between lateral line morphology and collective behaviour using two morphologically divergent species and their second-generation hybrids. We identify collective behaviours associated with variation in canal and superficial lateral line morphology, with closer proximities to neighbouring fish associated with larger canal pore sizes and fewer superficial neuromasts. A mechanistic understanding of the observed associations was provided by hydrodynamic modelling of an artificial lateral line sensor, which showed that simulated canal-based neuromasts were less susceptible to saturation during unidirectional movement than simulated superficial neuromasts, while increasing the canal pore size of the simulated lateral line sensor elevated sensitivity to vortices shed by neighbouring fish. Our results propose a mechanism behind lateral line flow sensing during collective behaviour in fishes.

Assessing the size-dependent effects of microplastics on zebrafish larvae through fish lateral line system and gut damage.

This study evaluated the size-dependent effects of high-density polyethylene (HDPE) fragments in zebrafish. Larvae were exposed to HDPE microplastic (MP) in three sizes, small (14.12μm), medium (80.32μm), and large (120.97μm), at 20mg/L. Size-dependent effects in terms of MP intake, subsequent gut damage, and behavioral changes were observed. The results showed that HDPE exposure did not affect the survivability of zebrafish larvae but caused two significant changes. First, exposure to large MPs caused the most serious damage to hair cells and mechanosensory receptors in the fish's lateral line system. Second, exposure to MPs<100μm resulted in their ingestion by larvae, thereby causing morphological changes in the gastrointestinal tract. All larvae exposed to MPs showed behavioral pattern changes associated with size differences. This study improves our understanding of the effects of MPs on aquatic organisms and highlights the need to implement efficient strategies for plastic waste management.

Bioinspired Stretchable Transducer for Wearable Continuous Monitoring of Respiratory Patterns in Humans and Animals.

A bio-inspired continuous wearable respiration sensor modeled after the lateral line system of fish is reported which is used for detecting mechanical disturbances in the water. Despite the clinical importance of monitoring respiratory activity in humans and animals, continuous measurements of breathing patterns and rates are rarely performed in or outside of clinics. This is largely because conventional sensors are too inconvenient or expensive for wearable sensing for most individuals and animals. The bio-inspired air-silicone composite transducer (ASiT) is placed on the chest and measures respiratory activity by continuously measuring the force applied to an air channel embedded inside a silicone-based elastomeric material. The force applied on the surface of the transducer during breathing changes the air pressure inside the channel, which is measured using a commercial pressure sensor and mixed-signal wireless electronics. The transducer produced in this work are extensively characterized and tested with humans, dogs, and laboratory rats. The bio-inspired ASiT may enable the early detection of a range of disorders that result in altered patterns of respiration. The technology reported can also be combined with artificial intelligence and cloud computing to algorithmically detect illness in humans and animals remotely, reducing unnecessary visits to clinics.

An underwater moving dipole tracking method of artificial lateral line based on intelligent optimization and recursive filter

Inspired by the lateral line system of fish, an artificial lateral line system is proposed for underwater target detection. The dipole is treated as a standard and simplified target. In previous studies, most researchers focused on the dipole at a fixed position and the trajectory tracking of a moving dipole was barely considered. In this paper, a new trajectory tracking method for a moving dipole is proposed. First, based on the instant pressure amplitude and loss function, the dipole trajectory is tracked by particle swarm optimization (PSO). Then, the PSO-tracked trajectory is optimized by using recursive filters such as a Kalman filter (KF) and a particle filter (PF) to reduce the tracking error. The experiment result showed that when the trajectory of the dipole was rectangular, the target tracking accuracy of PSO was competitive compared with the Gauss–Newton method. The mean error distance (MED) of PSO was 12.51 mm. The PF showed better optimization performance than the KF in this study, and the corresponding MED of the PF was 7.064 mm. The main factor that caused tracking errors was pressure mismatch. In the simulation, when pressure mismatch was not considered, the performance of the proposed dipole tracking method was highly improved.

Body-generated hydrodynamic flows influence male–male contests and female mate choice in a freshwater fish

The lateral line system of fishes is composed of neuromast mechanoreceptors that detect movement through vibration and changes in pressure gradients in the water. Although mechanosensory information has been shown to be important in the contexts of predator escape and foraging, little is known about the role of the lateral line system during intraspecific interactions, such as reproduction. However, many species of fish demonstrate complex courtship and aggressive repertoires that involve movement of the body and fins, resulting in local displacement of the surrounding water. This displacement has the potential to function as a signal that contains information about the sender. In this study, we conducted two behavioural experiments using fathead minnows, Pimephales promelas, to test the hypothesis that the outcomes of male–male contests and male–female courtship interactions are influenced by hydrodynamic flows generated during conspecific interactions. In the first experiment, we pitted control males against those with an ablated lateral line system and assessed both overall aggression and the likelihood of territory acquisition. In the second experiment, we conducted dual-choice female mate choice experiments to determine whether control females and those without access to mechanosensory information (ablated females) differed in patterns of discrimination and the use of courtship as a criterion of choice. In experiment 1, control males won a significantly greater proportion of territorial contests than expected by chance and were more likely to use noncontact threat displays during aggressive interactions compared with ablated males. In experiment 2, females with access to the mechanosensory information channel showed enhanced mate discrimination compared to ablated females. These data are among the first to show that mechanosensory signals are an important criterion of territorial and reproductive success in fishes and are likely important contributors to multimodal communication in this group.

A numerical study of target flow field detection by autonomous underwater vehicles

ABSTRACT Sideline is a key component of fish sensory system, which has been found to affect many behaviours of fish, including manoeuvring obstacle avoidance, prey tracking and environmental mapping in complex fluid environment. In this paper, based on the sensing flow field mechanism of fish lateral line system, a sphere obstacle model is established by using the CFD method and FLUENT software, and the flow field around it is simulated and calculated. The experiment controls two variables: water flow velocity and sphere size. In this paper, the influence of velocity and obstacle size on pressure distribution is analysed, and the rectangular coordinate system is established with the spherical centre as the origin, and the characteristics of pressure distribution in X and Y directions are summarised. This research plays an important role in promoting the development of autonomous underwater vehicles.

Simulation Study for Obstacle Avoidance of Autonomous Underwater Vehicles

Li, Y. and Zhang, M., 2020. Simulation study for obstacle avoidance of autonomous underwater vehicles. In: Yang, D.F. and Wang, H. (eds.), Recent Advances in Marine Geology and Environmental Oceanography. Journal of Coastal Research, Special Issue No. 108, pp. 104–108. Coconut Creek (Florida), ISSN 0749-0208.Fish can track their prey and detect their surroundings in a complex water environment because of their unique underwater perception advantage. In this paper, on the basis of the sensing flow-field environment mechanism of the fish lateral line system, by analyzing the sonar system of an autonomous underwater vehicle (AUV) and the sensing principle of the fish lateral line system, the obstacle model of two shapes is established by using ANSYS software with computational fluid dynamics (CFD) analysis method. Two characteristic variables of different flow velocity and obstacle size are combined to simulate the flow field. The flow field of the fluid through different shape obstacles is analyzed, and the variation of the flow velocity to the flow field around the obstacle is compared, with the aim to establish a method to actively perceive and analyze the surrounding flow-field information through the characteristic parameters (velocity, size, shape) of the underwater obstacle itself. This paper provides a novel idea and practical sensing means for underwater detection technology, which can fill the void left by sonar and vision systems in a chaotic water environment. Improving the adaptive ability of AUV flow field and providing the theoretical basis for realizing the bionic lateral line engineering in the future, this research has an important impetus to the development of AUVs.

Ammonia exposure impairs lateral-line hair cells and mechanotransduction in zebrafish embryos

Ammonia (including NH3 and NH4+) is a major pollutant of freshwater environments. However, the toxic effects of ammonia on the early stages of fish are not fully understood, and little is known about the effects on the sensory system. In this study, we hypothesized that ammonia exposure can cause adverse effects on embryonic development and impair the lateral line system of fish. Zebrafish embryos were exposed to high-ammonia water (10, 15, 20, 25, and 30 mM NH4Cl; pH 7.0) for 96 h (0–96 h post-fertilization). The body length, heart rate, and otic vesicle size had significantly decreased with ≥15 mM NH4Cl, while the number and function of lateral-line hair cells had decreased with ≥10 mM NH4Cl. The mechanoelectrical transduction (MET) channel-mediated Ca2+ influx was measured with a scanning ion-selective microelectrode technique to reveal the function of hair cells. We found that NH4+ (≥5 mM NH4Cl) entered hair cells and suppressed the Ca2+ influx of hair cells. Neomycin and La3+ (MET channel blockers) suppressed NH4+ influx, suggesting that NH4+ enters hair cells via MET channels in hair bundles. In conclusion, this study showed that ammonia exposure (≥10 mM NH4Cl) can cause adverse effects in zebrafish embryos, and lateral-line hair cells are sensitive to ammonia exposure.

A cerebellum-like circuit in the lateral line system of fish cancels mechanosensory input associated with its own movements.

An animal's own movement exerts a profound impact on sensory input to its nervous system. Peripheral sensory receptors do not distinguish externally generated stimuli from stimuli generated by an animal's own behavior (reafference) - although the animal often must. One way that nervous systems can solve this problem is to provide movement-related signals (copies of motor commands and sensory feedback) to sensory systems, which can then be used to generate predictions that oppose or cancel out sensory responses to reafference. Here, we studied the use of movement-related signals to generate sensory predictions in the lateral line medial octavolateralis nucleus (MON) of the little skate. In the MON, mechanoreceptive afferents synapse on output neurons that also receive movement-related signals from central sources, via a granule cell parallel fiber system. This parallel fiber system organization is characteristic of a set of so-called cerebellum-like structures. Cerebellum-like structures have been shown to support predictive cancellation of reafference in the electrosensory systems of fish and the auditory system of mice. Here, we provide evidence that the parallel fiber system in the MON can generate predictions that are negative images of (and therefore cancel) sensory input associated with respiratory and fin movements. The MON, found in most aquatic vertebrates, is probably one of the most primitive cerebellum-like structures and a starting point for cerebellar evolution. The results of this study contribute to a growing body of work that uses an evolutionary perspective on the vertebrate cerebellum to understand its functional diversity in animal behavior.

BTO/P(VDF-TrFE) Nanofiber-based Artificial Lateral Line Sensor with Drag Enhancement Structures

A flexible Artificial Lateral Line (ALL) sensor is presented in this paper, featuring a barium titanate/polyvinylidene fluoride-trifluoroethylene [BTO/P(VDF-TrFE)] nanofiber mat, a hydrogel cupula, and a constriction structure in the canal.. The excellent piezoelectric performance of the BTO/P(VDF-TrFE) nanofiber, superior to that of a pristine P(VDF-TrFE) nanofiber, helps improve the sensitivity of the ALL sensor. The hydrogel cupula imitating the cupula in a fish lateral line system enhances the ALL sensitivity through a material-induced drag enhancement mechanism. The constriction mimics the diminution structure found in fish canal lateral line systems, endowing the canal ALL sensor with enhanced sensitivity through a structure-induced drag enhancement mechanism. The contributions of the hydrogel cupula and constriction structure in offering an enhanced sensing performance are studied experimentally, in comparison with conventional ALL sensors. The constriction structure in the canal helps modify the frequency response of the canal ALL sensor, i.e., attenuating low frequencies while amplifying high frequencies. The proposed biomimetic flow sensor is expected to aid in the development of smart skins for underwater robotics applications.

Research on an Artificial Lateral Line System Based on a Bionic Hair Sensor with Resonant Readout.

Inspired by the lateral line system of fish, an artificial lateral line system based on bionic hair sensor with resonant readout is presented in this paper. An artificial lateral line system, which possesses great application potential in the field of gas flow visualization, includes two different sensors: a superficial neuromast and a canal neuromast flow velocity sensor, which are used to measure the constant and oscillatory air flow velocity, respectively. The sensitive mechanism of two artificial lateral line sensors is analyzed, and a finite element simulation is implemented to verify the structural design. Then the control circuit of the artificial lateral line system is designed, employing a demodulation algorithm of oscillatory signal based on the least mean square error algorithm, which is used to calculate the oscillatory air flow velocity. Finally, the experiments are implemented to assess the performance of the two artificial lateral line systems. The experimental results show that the artificial lateral line system, which can be used to measure the constant and oscillatory air flow velocity, has a minimum threshold of 0.785 mm/s in the measurement of oscillatory air flow velocity. Moreover, the artificial canal neuromast lateral line system can filter out low-frequency disturbance and has good sensitivity for high-frequency flow velocity.

Constriction canal assisted artificial lateral line system for enhanced hydrodynamic pressure sensing

With the assistance of mechanosensory lateral line system, fish can perceive minute water motions in complex underwater environments. Inspired by the constriction within canal nearby canal neuromast in fish lateral line system, we proposed a novel canal artificial lateral line (CALL) device with constriction in canal nearby the sensing element. The designed CALL device consisted of a poly(vinylidene fluoride-trifluoroethylene)/polyimide cantilever as the sensing element and a polydimethylsiloxane (PDMS) microfluid canal. Two types of CALL devices, i.e., CALL with straight canal (S-CALL) and CALL with constriction canal (C-CALL), were developed and characterized employing a dipole source. Experimental results showed that the proposed C-CALL device achieved a pressure gradient detection limit of 0.64 Pa m−1, which was much lower than the S-CALL device. It indicates that the constriction in the canal nearby the sensing element could enhance the hydrodynamic pressure sensing performance of the CALL device. In addition, the constriction could modify the frequency response of the CALL device, and the C-CALL device achieved higher voltage output than S-CALL in high-frequency domain.

Performance evaluation and analysis for dipole source localization with lateral line sensor arrays

The unique mechanosensory lateral line system of fish inspires a novel and promising sensing scheme in dealing with the challenges that autonomous underwater vehicles (AUVs) face in underwater localization and navigation. In this paper, the quantitative and method-independent Cramer–Rao lower bound (CRLB) model is established to evaluate the practical performance of a lateral line sensor array (LLSA) for dipole source localization by considering the excitation pattern mismatches and the measurement noises. The effective localization area of the LLSA is studied under varying array lengths and sensor densities. Localizations for the LS (least squares) method and the MUSIC (multiple signal classification) method are compared in simulations. It is shown that the longer and denser the LLSA, the larger the effective localization area. Typically, the too separated sensor-to-sensor spacing deteriorates the near-body localization performance. The effective localization area obtained by employing the LS method matches the CRLB analysis, which also proves the validity of the analytical CRLB model. Besides, the MUSIC method presents smaller effective localization areas than the LS method. Physical experiments are also conducted and agree well with the CRLB analysis. Further study shows that the measurement noises have an equivalent effect on the excitation pattern mismatches, and can be effectively suppressed by choosing a large number of snapshots. In addition, the CRLB gives the perceptual distance that is consistent with the observation. At last, guidance on the design of a simplified LLSA with the least number of sensors and an optimal sensor-to-sensor spacing is provided for AUVs.

A pressure difference sensor inspired by fish canal lateral line

It is of interest to exploit the insight from the lateral line system of fish for flow sensing applications. In this paper, a novel fish canal lateral line-inspired pressure difference sensor is proposed by embedding an ionic polymer-metal composite (IPMC) sensor within a canal filled with viscous fluid. Such a sensor could be used by underwater robots and vehicles for object detection, angle of attack measurement, and source localization. Unlike the biological counterpart that has open ends on the surface of the body, the proposed sensor has two pores covered with a latex membrane, which prevents the canal fluid from mixing with the ambient fluid. The design and fabrication of the sensor are presented, where the sensor is integrated with a fish-like body. The sensor output is experimentally characterized as the fish-like body is rotated with respect to a dipole source, which confirms that the sensor is capable of capturing the pressure difference between the two pores. Finite element modeling and simulation that capture fluid-structure interactions and IPMC physics are conducted to shed light on the sensor behavior. Finally, the utility of the sensor in underwater robotics is illustrated via orienting the fish-like body towards the dipole source using feedback from the proposed sensor.

Sensory ecology of the fish lateral‐line system: Morphological and physiological adaptations for the perception of hydrodynamic stimuli

Fishes are able to detect and perceive the hydrodynamic and physical environment they inhabit and process this sensory information to guide the resultant behaviour through their mechanosensory lateral-line system. This sensory system consists of up to several thousand neuromasts distributed across the entire body of the animal. Using the lateral-line system, fishes perceive water movements of both biotic and abiotic origin. The anatomy of the lateral-line system varies greatly between and within species. It is still a matter of debate as to how different lateral-line anatomies reflect adaptations to the hydrodynamic conditions to which fishes are exposed. While there are many accounts of lateral-line system adaptations for the detection of hydrodynamic signals in distinct behavioural contexts and environments for specific fish species, there is only limited knowledge on how the environment influences intra and interspecific variations in lateral-line morphology. Fishes live in a wide range of habitats with highly diverse hydrodynamic conditions, from pools and lakes and slowly moving deep-sea currents to turbulent and fast running rivers and rough coastal surf regions. Perhaps surprisingly, detailed characterisations of the hydrodynamic properties of natural water bodies are rare. In particular, little is known about the spatio-temporal patterns of the small-scale water motions that are most relevant for many fish behaviours, making it difficult to relate environmental stimuli to sensory system morphology and function. Humans use bodies of water extensively for recreational, industrial and domestic purposes and in doing so often alter the aquatic environment, such as through the release of toxicants, the blocking of rivers by dams and acoustic noise emerging from boats and construction sites. Although the effects of anthropogenic interferences are often not well understood or quantified, it seems obvious that they change not only water quality and appearance but also, they alter hydrodynamic conditions and thus the types of hydrodynamic stimuli acting on fishes. To date, little is known about how anthropogenic influences on the aquatic environment affect the morphology and function of sensory systems in general and the lateral-line system in particular. This review starts out by briefly describing naturally occurring hydrodynamic stimuli and the morphology and neurobiology of the fish lateral-line system. In the main part, adaptations of the fish lateral-line system for the detection and analysis of water movements during various behaviours are presented. Finally, anthropogenic influences on the aquatic environment and potential effects on the fish lateral-line system are discussed.

Artificial Hair-Like Sensors Inspired from Nature: A Review

Nature creatures have evolved excellent receptors, such as sensory hairs in arthropods, lateral line system of fishes. Researchers inspired by nature creatures have developed various mechanical sensors. Here, we provide an overview on the development of Artificial Hair-Like (AHL) sensors based on the inspiration of hair flow sensory receptors, especially sensory hairs in arthropods and lateral line systems of fishes. We classify the developed AHL sensors into several categories according to the operating principles they based on, for example, piezoresistive and piezoelectric effects. The current challenges and existing problems in the development of AHL sensors are also present, which were primarily restricted by the exploratory tools of sensing mechanism of creatures and current manufacturing technologies. In future, more efforts are required in order to further improve the performance of AHL sensors. We expect that intelligent multi-functional AHL sensors can be applied not only in applications like navigation of underwater automatic vehicles, underwater search and rescue, tap-water metering, air monitoring and even in medicare, but also potentially be used in space robots to detect complex topography.

Fine structure of the canal neuromasts of the lateral line system in the adult zebrafish.

The mechanosensory lateral line system of fish is responsible for several functions such as balance, hearing, and orientation in water flow and is formed by neuromast receptor organs distributed on head, trunk and tail. Superficial and canal neuromasts can be distinguished for localization and morphological differences. Several information is present regarding the superficial neuromasts of zebrafish and other teleosts especially during larval and juvenile stages, while not as numerous data are so far available about the ultrastructural characteristics of the canal neuromasts in adult zebrafish. Therefore, the aim of this study was to investigate by transmission electron microscopy the ultrastructural aspects of cells present in the canal neuromasts. Besides the typical cellular aspects of the neuromast, different cellular types of hair cells were observed that could be identified as developing hair cells during the physiological turnover. The knowledge of the observed cellular types of the canal neuromasts and their origin could give a contribution to studies carried out on adult zebrafish used as model in neurological and non-neurological damages, such as deafness and vestibular disorders.