Swimming Speed Of Fish Research Articles

Effects of size and sex on swimming performance and metabolism of invasive mosquitofish Gambusia holbrooki

AbstractIn freshwater ecosystems, abiotic factors such as flow regime and water quality are considered important predictors of ecosystem invasibility. The aim of this study was to investigate the critical swimming capacity and metabolism of the eastern mosquitofish, Gambusia holbrooki, focusing on sex and size effects, to evaluate the influence of water flow on its invasive success. Specimens of mosquitofish were captured from the Ter Vell lagoon (L'Estartit, north‐eastern Spain) in July 2014, and we measured the critical swimming speed (Ucrit) and oxygen consumption of individual fish (30 females and 30 males) using a mini swim tunnel. The mean Ucrit of this poeciliid fish was estimated at 14.11 cm·s−1 (range = 4.85–22.26), which is lower than that of many other fishes of similar size and confirms that this species is limnophilic and its invasive success might be partially explained by hydrologic alterations. However, the Ucrit and maximal metabolic rate vary markedly with fish size and sex, with males having much higher values for the same body mass, and thus probably being more resistant to strong water flows. Multiple regression models illustrate that multivariate analyses might increase the predictive power and understanding of swimming performance and metabolic traits, compared to results from conventional simple regressions.

Evolutionarily Stable Strategies for Fecundity and Swimming Speed of Fish.

Many pelagic fish species have a life history that involves producing a large number of small eggs. This is the result of a trade-off between fecundity and larval survival probability. There are also trade-offs involving other traits, such as larval swimming speed. Swimming faster increases the average food encounter rate but also increases the metabolic cost. Here we introduce an evolutionary model comprising fecundity and swimming speed as heritable traits. We show that there can be two evolutionary stable strategies. In environments where there is little noise in the food encounter rate, the stable strategy is a low-fecundity strategy with a swimming speed that minimises the mean time taken to reach reproductive maturity. However, in noisy environments, for example where the prey distribution is patchy or the water is turbulent, strategies that optimise mean outcomes are often outperformed by strategies that increase inter-individual variance. We show that, when larval growth rates are unpredictable, a high-fecundity strategy is evolutionarily stable. In a population following this strategy, the swimming speed is higher than would be anticipated by maximising the mean growth rate.

Application of Taguchi Method in the Optimization of Swimming Capability for Robotic Fish

In this paper, we applied the Taguchi method to evaluate the maximum swimming speed of a robotic fish under the limitation of the output of the motor. Four factors were considered in the optimization: the caudal-fin aspect ratio, the caudal fin stiffness, the oscillating frequency and the stiffness of the spring that transmits forces from the actuators to the foil. Because of the power limitations, the parameter's space was irregular. Since the Taguchi method requires a regular parameter space, we divided the parameter space into a regular space and the remaining irregular spaces. Within only 25 trials, the frequency and the spring stiffness were determined as the main factors in the regular space by the orthogonal design. Six more trials were carried out in the remaining irregular space with a higher frequency and spring stiffness. The fastest swimming speed of 870 mm/s, approximately 2.6 BL ( Body Lengths)/ s, was acquired, when the frequency reached 12 Hz and with infinite spring stiffness. This method is efficient for exploring the maximum locomotor capabilities of robotic fish and may also be useful for other robots as no modelling is required.

Herring perform stronger collective evasive reactions when previously exposed to killer whales calls

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-cage on a large wild-caught Atlantic herring school (~60000 individuals). First, we tested whether herring schooling dynamics changed in response to vocalizations of killer whales (feeding calls), a main predator of herring in the wild. We also investigated if herring collective evasive reactions during simulated attacks varied after pre-exposure to killer whale vocalizations. Collective escape reactions (collective diving) were stronger when herring were previously exposed to killer whale vocalizations. However, herring did not modify their schooling dynamics (e.g., school density, school vertical distribution in the water column, fish swimming speed, or correlation strength between individuals, that measures how aligned the fish are as a function of distance) in response to the killer whale feeding calls alone. Overall, our results demonstrate that structural and dynamic changes at the school-level are not necessarily required for the execution of strong collective escape maneuvers, but risk awareness influences collective responsiveness and information transfer among schooling fish.

Empirical Modelling of Solid-blocking Effect in a Blazka Respirometer for Gag, a Large Demersal Reef Fish

The effect of solid-body blocking in a large (257 l) Blazka-style respirometer was examined in gag Mycteroperca microlepis. Gag ranging from 376-690 mm total length were tested at velocities from 10 to 91 cm s-1. The solid blocking effect (SBE) due to fish size, swimming speed, and water temperature was investigated by direct measurement of flow velocity at the area of the fish's maximum girth as compared to measurements at the rear (center) of the swimming chamber. Three models were compared as corrections for the SBE: the standard Bell and Terhune (BT), a novel modification of the Bell and Terhune (MBT) developed in this study, and the Bernoulli equation. Although the fit was good, the commonly used BT model consistently underestimated solid-blocking effect over the speeds tested (R2 adj = 0.980) whereas the MBT and Bernoulli models provided better fits (both with R2 adj = 0.993). The MBT model, with refined parameters for the fish body shape coefficient and fractional surface area exponent, yielded the best fit for observed data across all speeds for which gag were tested. This study also demonstrated that in Blazka-style respirometers, corrections were needed to account for SBE where fish occupied >10% of the cross-sectional area of the swimming chamber.

Modelling swimming activities and energetic costs in European sea bass (Dicentrarchus labrax L., 1758) during critical swimming tests

Muscular activity patterns in red and white muscles linked to oxygen consumption were studied during critical swimming tests in the sea bass (Dicentrarchus labrax Linnaeus 1758). The species is one of the most important for Mediterranean Sea aquaculture. A sigmoid model was used to fit both the oxygen consumption and red muscle activity while the white muscle activity pattern was described by an exponential model. Red muscle reaches an activation plateau close to critical swimming speed mostly due to the oxygen diffusion velocity in tissues. The exponential activation of white muscle appears to be linked to short and sudden periods of great energy need to cope with adverse conditions such as predation and escape. Both oxygen consumption and muscular activity were found to be size dependent. The bioenergetics of sea bass was modelled based on fish mass and swimming speed to predict the minimum and maximum speed as well as the mass-specific active metabolic rate and standard metabolic rate. An important finding was that contrary to other well-known species, swimming at subcritical speeds in sea bass involves both red and white muscle in different proportions.

Atlantic salmon Salmo salar instantaneously follow vertical light movements in sea cages

Atlantic salmon in marine farming environments are exposed to potentially detri- mental conditions through space and time. For instance, the vertical distribution of parasitic salmon lice larvae shifts in response to changing salinity conditions. We examined whether stock can be moved away from harmful depths using constant-rate vertical movements of lights at night over short periods. Salmon held in research-scale sea cages were exposed to light movements between depths of 0�12 m and at 5 different speeds (1, 2, 4, 8 and 16 m min �1 ) on 3 nights. Fish were acclimated to lights fixed at 8 m depth in a temperature- and salinity-stratified cage environ- ment, partitioning salmon into surface-positioned (47%) and light-positioned subgroups (53% of the population). A high proportion (50�65%) of the light-positioned group followed lights be - tween upper and lower cage sections when moved up to a critical speed of 4 m min �1 . However, the surface-positioned group always persisted. Following decreased when lights were moved at higher speeds, equivalent to or faster than fish swimming speeds measured under fixed lighting. Instantaneous vertical light movements at night may effectively move salmon away from fluctuat- ing unsuitable depths (e.g. lice-rich depths), into temporary favourable depths (e.g. surface brack- ish waters to treat against stenohaline parasites), and throughout cages to avoid crowding in nar- row depth ranges.

Sperm traits dependent on body size in masu salmon Oncorhynchus masou

Most comparative studies on the sperm traits (sperm concentration, swimming speed, and longevity) of salmonid fish involve males with alternative life histories (anadromous versus resident forms) that exhibit different reproductive strategies. However, males exhibit a dominance hierarchy within the same life history, in which smaller males have a tendency to be lower rank. This phenomenon prompted us to compare the sperm traits of large anadromous and small resident males in masu salmon Oncorhynchus masou, and to identify the size-dependent sperm traits within these two life history groups. We detected a significant difference in sperm concentration between the two groups, with resident males having higher sperm concentrations than anadromous males. For resident males, we detected a significantly negative correlation between body size and sperm swimming speed, i.e., faster sperm speed was associated with smaller body size. These findings support earlier data and suggest that smaller or younger males utilize more energy to produce high concentration and high speed sperms.

Effects of crude oil and dispersed crude oil on the critical swimming speed of puffer fish, Takifugu rubripes.

In order to examine the effects of crude oil and dispersed crude oil (DCO) on the swimming ability of puffer fish, Takifugu rubripes, the critical swimming speeds (U crit) of fish exposed to different concentrations of water-soluble fraction (WSF) of crude oil and DCO solution were determined in a swimming flume. WSF and DCO significantly affected the U crit of puffer fish (p < 0.05). The U crit of puffer fish exposed to 136 mg L(-1) WSF and 56.4 mg L(-1) DCO decreased 48.7 % and 43.4 %, respectively. DCO was more toxic to puffer fish than WSF. These results suggested that crude oil and chemically dispersed oil could weaken the swimming ability of puffer fish.

Evaluation approaches of fish swimming performance

Swimming speeds are the most important index for the evaluation of the fish swimming performance. The terminologies and classifications of the fish swimming performance were summarized in this paper. Taking into consideration of the widely used evaluation approaches of the fish swimming performance by different researchers, a recommended classification methodology of the fish swimming performance was proposed by the authors. And a new concept of the swimming speed, the Maximum Domed Swimming Speed (DSS), was introduced into this new classification framework together with a discussion on its calculation method and the practical significance. According to the classification system, the fish swimming speeds are classified into five categories: Optimum Swimming Speed, Maximum Sustained Swimming Speed, Critical Swimming Speed, Maximum Domed Swimming Speed, and Burst Swimming Speed. Other concepts of swimming speeds are generally merged into the above five categories, respectively. Furthermore, possible relevancies among the Maximum Sustained Swimming Speed (MSS), the Critical Swimming Speed (CSS), and the Maximum Domed Swimming Speed (DSS) were discussed. It was concluded that these three swimming speeds, in a sense, can be regarded as the equivalent indices for the evaluation of fish swimming performance.

Experimental Investigation to the Kinematics of a Blue Spotted Ray like Underwater Propulsor

Engineers have long been impressed by the swimming speed and agility of fish. Their research effort has been focusing on the development of a new technique of propulsion by mimicking biological fish. The aim of the present work is to develop a biological inspired underwater propulsor that emulates the performance of bluspotted ray. We first measured the morphology and captured the movement of a real bluespotted ray to provide some useful references for biomimetic mechanism design. By virtue of the modular and reconfigurable design concept, a bluspotted ray like underwater propulsor was considered and developed. An experiment system was set up to investigate the effect of various kinematic parameters including frequency, amplitude, wavelength on the propulsion velocity, thrust and efficiency of the fish robot. The results show that the designed biomimetic underwater propulsor is able to propel itself effectively.

Chronic Hypoxia Exposure of Trout Embryos Alters Swimming Performance and Cardiac Gene Expression in Larvae

Hypoxia exposure during embryonic development of rainbow trout causes developmental delay and bradycardia and alters the ontogeny of cardiac regulatory control mechanisms. The purpose of this study was to characterize how hypoxia exposure from the day of fertilization until stage 34 (57 d postfertilization) affects the aerobic fitness and growth of the hatched fish at multiple stages. In addition, we characterized the expression of gene transcripts for seven troponin I (TnI) isoforms to examine the effect of hypoxia treatment on cardiac muscle development. Results demonstrate that the critical swimming speed of the hypoxia-exposed fish was significantly less than that of the control group at stage 35 and the fry stage. Growth was reduced in the hypoxia-treated fish between stages 35 and 37, as was the relative lipid content at stage 37. Finally, six TnI isoforms were found in all hearts. One of these isoforms, RTcTnI, decreased in abundance between stage 35 and the fry stage, but hypoxia-exposed fish had higher levels than did controls at the fry stage. The abundance of AScTnI2 was significantly lower in hypoxia-exposed fry fish than in controls. These results indicate that chronic hypoxia exposure during embryonic development has long-term consequences on aerobic fitness, growth, and cardiac gene expression following hatch.

The effects of diel-cycling hypoxia acclimation on the hypoxia tolerance, swimming capacity and growth performance of southern catfish (Silurus meridionalis)

To investigate the effects of diel-cycling hypoxia acclimation on the hypoxia tolerance, swimming and growth performance of juvenile southern catfish, we initially measured the critical oxygen tension (Pcrit), oxygen thresholds of aquatic surface respiration (ASR) and loss of equilibrium (LOE) of diel-cycling hypoxia-acclimated (15d, 7:00–21:00, dissolved oxygen level (DO)=7.0±0.2mgL−1; 21:00–7:00, DO=3.0±0.2mgL−1) and non-acclimated (15d, DO=7.0±0.2mgL−1) southern catfish at 25°C. We then measured the critical swimming speed (Ucrit) and metabolic rate (MR) of hypoxia-acclimated and non-acclimated fish (under both hypoxic and normoxic conditions). The feeding rate (FR), feeding efficiency (FE) and specific growth rate (SGR) of fish in hypoxia-acclimated and non-acclimated groups were also measured. The Pcrit, ASR and LOE of hypoxia-acclimated fish were significantly lower than those of non-acclimated fish. Hypoxia acclimation resulted in a significantly higher Ucrit when the individuals swam in hypoxia. The Ucrit, maximum metabolic rate (MMR) and metabolic scope (MS) of both the hypoxia-acclimated and non-acclimated fish all decreased with the decrease of DO. However, the Ucrit, MMR and MS decreased by 31, 43 and 54%, respectively, in non-acclimated fish, whereas these values decreased by 15, 28 and 29%, respectively, in hypoxia-acclimated fish, which suggests that hypoxia-acclimated fish were less sensitive to the DO decrease. The FR, FE and SGR all decreased by 21, 20 and 45%, respectively, in the hypoxia-acclimated group compared to the non-acclimated group. This result suggests that diel-cycling hypoxia acclimation improved the hypoxia tolerance and aerobic swimming performance of southern catfish, whereas impaired the growth performance. The high hypoxia tolerance and physiological plasticity to hypoxia-acclimated southern catfish may be related to its lower maintenance energy expenditure, sit-and-wait lifestyle and bottom-dwelling living environment condition (usually facing oxygen fluctuation). The growth performance of so-called ‘visceral type’ fish species, such as southern catfish, are more sensitive to hypoxia compared to other fish species because of their high peak post-prandial metabolic rate, which may be restrained by the limited aerobic metabolic scope in hypoxia.

Effects of dissolved carbon dioxide on energy metabolism and stress responses in European seabass (Dicentrarchus labrax)

Elevated carbon dioxide concentrations reduce feed intake and growth in several fish species and induce stress responses. In this study, the effects of moderately elevated CO2 levels on performance, energy partitioning, swimming activity and stress response in European seabass were assessed. European seabass (140.0 g) were reared under two levels of CO2 (1.6 and 7.0 mg L-1) and two feeding levels (FLs) (maintenance and satiation) for 60 days, and fish swimming speed was recorded. At the end of the experiment, fish were subjected to an acute stress test. Blood cortisol, glucose and lactate were analysed. Energy and nitrogen balances were quantified based on measurements of body composition and digestibility coefficients. Moderately elevated chronic CO2 level did neither affect energy requirements for maintenance nor the utilization of digestible energy for growth. However, swimming activity data suggests that FL dependent alterations in energy partitioning took place. Blood cortisol values after the acute stress were affected by additional CO2 exposure and this effect was also dependent on FL. The elevated CO2 exposure of 7.0 mg L-1 appears to act as a chronic stressor as adaptive responses took place, however, this CO2 exposure seems to be still within the allostatic load of the fish.

Flow Characteristic Variations on Groyne Types for Aquatic Habitats

The field formed by groyne has the function of aquatic habitats for the underwater biology. The characteristic of groyne field occurring around downstream of groyne depends on groyne type and shape. Thus to maximize the function of groyne, it needs to understand the flow characteristic around groyne. In this study, experiment model test was conducted in recirculation zone located in downstream of groyne. Groyne types for experiment are three: permeable, impermeable and inclined crest groyne. LSPIV (Large Scale Particle Image Velocimetry) is used to measure flow field around the groyne and it revealed flow characteristic in recirculation zone at each case. In order to estimate the aquatic habitats of groyne fields, critical swimming speed of major fleshwater fish in Korea was compared with the variation of velocity distribution in groyne fields. From the results, the rate of velocity decreases in groyne fields, V/Vapp were measured to be 0 to 0.5 and the results can be fundamental data which are used to estimate the aquatic habitable function of groyne.

Barriers to fish passage and barriers to fish passage assessments: the impact of assessment methods and assumptions on barrier identification and quantification of watershed connectivity

Barriers (culverts and dams) can impede fish passage and affect the overall habitat connectivity of rivers. However, a challenge lies in how to conceptualize and adequately measure passability at barriers. We hypothesize that estimates of barrier and watershed connectivity are dependent on assumptions about the nature of passability, and how it is measured. Specifically, we compare passability estimates in Terra Nova National Park, Canada for individual barriers for two barrier assessment methods (a rapid assessment and one based on FishXing software), two salmonid species, different fish sizes and swimming speeds, and varying hydrological conditions. Watershed connectivity was calculated using the Dendritic Connectivity Index (DCI). Lastly, we test to see what the impact of the various factors is on the practical goal: prioritizing barriers for restoration. Our results show that barrier passability estimates can vary drastically for some barriers (0–100%). In general, the rapid field-based assessment tended to give more conservative estimates of passability than those based on FishXing. Estimates of watershed connectivity were not as sensitive to the assumptions and methods used (DCI: 40–83). Fish size had the greatest effect on DCI. Importantly, variation in DCI had little impact on the restoration priorities. The same barrier was retained as the top priority >96% of the time. Thus, managers wishing to assess barriers for restoration need to carefully consider how passability is to be measured, but can reduce the impact of these decisions by considering barriers in their watershed context using a connectivity index such as the DCI.

음향카메라시스템을 이용한 낙동강어도의 어류모니터링

This study investigated a method for monitoring fishes immigrating to upper streams from the sea in relation to water level with elapsed time, and measured fish behavior patterns and swimming speed in a fishing boat gateway using an acoustic camera system. This method was employed due to difficulties, linked to high turbidity, of using only underwater optical systems for monitoring fish migrating to brackish water. Results showed that fish length distribution showed high correlation between haul sampling and an automatic counting algorithm supported by the DIDSON software program. These results will help to maximize the effects of fish run management by increasing understanding of the amount of major fish species migrating in relation to durable water levels.

The hypoxia avoidance behaviour of juvenile Atlantic cod (Gadus morhua L.) depends on the provision and pressure level of an O2 refuge

The frequency of low O2 (hypoxia) has increased in coastal marine areas but how fish avoid deleterious water masses is not yet clear. To assess whether the presence and oxygen pressure (PO2) level of an O2 refuge affects the hypoxia avoidance behaviour of fish, individual Atlantic cod (Gadus morhua L.) were exposed to a range of O2 choices in a 2-way choice chamber at 11.4°C over two different experiments. Cod in the first experiment were allowed access to a fixed O2 refuge (fully air-saturated seawater) whilst oxygen pressure (PO2) on the other side was reduced in steps to a critically low level, i.e. 4.3 kPa—a point where cod can no longer regulate O2 consumption. Under these conditions, cod did not avoid any level of hypoxia and fish swimming speed also remained unchanged. In contrast, strong avoidance reactions were exhibited in a second experiment when fish were again exposed to 4.3 kPa but the safety, i.e. PO2, of the refuge was reduced. Fish not only spent less time at 4.3 kPa as a result of fewer sampling visits but they also swam at considerably slower speeds. The presence of an avoidance response was thus strongly related to refuge PO2 and it is unlikely that cod, and possibly other fish species, would enter low O2 to feed in the wild if a sufficiently safe O2 refuge was not available. It is therefore hypothesized that the feeding range of fish may be heavily compressed if hypoxia expands and intensifies in future years.

Rainbow trout Oncorhynchus mykiss energetic responsesto pulsed flows in the American River, California, assessed by electromyogram telemetry

Although rainbow trout Oncorhynchus mykiss within the American River, California, apparently exhibit minimal upstream or downstream movements in response to hydroelectric-power-generation-related pulsed flows, the associated energetic costs are unknown. We implanted rainbow trout (n = 9, ≥30 cm SL) with electromyogram (EMG)-sensor-equipped radio transmitters to assess the swimming behavior and associated energetic costs associated with their responses to pulsed flows. Using laboratory calibrations in a Brett-type swimming respirometer, the trouts’ swimming speeds and oxygen consumption rates were estimated for their in-river EMG data, through a complete hydroelectric power-generation river pulsed-flow sequence (pre-pulse, increasing flow, peak, and decreasing flow stages), on several (mean: 3.2) sampling dates. Using a mixed-linear model, we found that fish swimming speed estimates increased during the increasing flow stage, while the associated mean oxygen consumption rates also increased at this stage. At river flows near the usual peak (>44 m3s−1), swimming speeds and movement rates decreased, possibly due to the fish using the river’s habitat complexities as hydraulic cover. We conclude that rainbow trout incur increased swimming-related energetic costs during increasing flows and, potentially, decreased foraging opportunities at high flows.

Development of a two‐joint robotic fish for real‐world exploration

AbstractResearch on biomimetic robotic fish has been undertaken for more than a decade. Various robotic fish prototypes have been developed around the world. Although considerable research efforts have been devoted to understanding the underlying mechanism of fish swimming and construction of fish‐like swimming machines, robotic fish have largely remained laboratory curiosities. This paper presents a robotic fish that is designed for application in real‐world scenarios. The robotic fish adopts a rigid torpedo‐shaped body for the housing of power, electronics, and payload. A compact parallel four‐bar mechanism is designed for propulsion and maneuvering. Based on the kinematic analysis of the tail mechanism, the motion control algorithm of joints is presented. The swimming performance of the robotic fish is investigated experimentally. The swimming speed of the robotic fish can reach 1.36 m/s. The turning radius is 1.75 m. Powered by the onboard battery, the robotic fish can operate for up to 20 h. Moreover, the advantages of the biomimetic propulsion approach are shown by comparing the power efficiency and turning performance of the robotic fish with that of a screw‐propelled underwater vehicle. The application of the robotic fish in a real‐world probe experiment is also presented. © 2010 Wiley Periodicals, Inc.