No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
INFLUENCE OF TURBIDITY ON FISH SCHOOL BEHAVIOR OF PLECOGLOSSUS ALTIVELIS ALTIVELIS IN STATIC WATER
Abstract
The water includes turbidity during and after the flood. Almost fish uses eyes and lateral line during swimming, so that the turbidity may effect on the swimming behavior of school of fish. However, there are few study on relations between the turbidity and swimming behavior of school of fish. In this study, the swimming behaviors of school of ayu, Plecoglossus altivelis altivelis, by changing turbidity and the number of fish in static water, were recorded with a digital video camera. It was found that the fish school is divided to some fish school with an increase of turbidity. This is because ayu can not find the other individual by view due to turbidity. In addition, the distance between each ayu and school of fish radius decrease with an increase of turbidity.
ResearchGate has not been able to resolve any citations for this publication.
Turbidity has both positive and negative effects on prey detection, by increasing or diminishing the contrast between prey and background due to the scattering of light. The positive effect of turbidity on prey contrast depends on the optical properties, scattering properties of suspended particles and the visual sensitivity of the predator. The positive effect of turbidity is pronounced for larval fish, given that their visual field is short, leaving fewer particles between them and their prey to scatter light and interfere with detection. This relationship, together with a decreased risk of predation, makes turbid environments more optimal for some species and size groups of fish (planktivores and fish larvae) and less so for others (adult piscivore fish). Thus, turbidity might have a structuring effect on a fish community. Recently it has been demonstrated that UV light might have positive effects on prey detection and consumption. How UV light might interact with different kinds of particles producing turbidity is not well documented.
The rheotaxis of fish generally has been understood to depend on the mechanical receptors like the lateral line and cutaneous sensations and, since lyon's report in 1904, the function of visual sense has been strongly emphasized. In this study the upstreaming reaction of freshwater fishes was examined under bright and dark conditions, with a rotating water trough devoid of visual objects. Behaviour of eight species of freshwater fishes in the current (17.4 cm/s) were compared under three different grades of illumination (4.0, 0.15 and 0.10 Lux) in the darkened laboratory. The results of the experiments are as follows; Under bright condition (4.0 Lux) fish in the current without visual objects showed a weak upstream movement, whereas under dark conditions (0.15 and 0.10 Lux) a vigorous upstream movement was shown. It seemed to be attributed to the compensational reaction by the mechanical receptors which allowed the fish to react positively against the current, without the visual objects under dark conditions. Other experiments at night and in turbid water also were conducted for comparison with the results of observations in the daytime. These data then are consistent with the view on the upstream movement of fish mentioned above. © 1982, The Japanese Society of Fisheries Science. All rights reserved.
Resource managers need to predict effects of pollution episodes on aquatic biota, and suspended sediment is an important variable in considerations of freshwater quality. Despite considerable research, there is little agreement on environmental effects of suspended sediment as a function of concentration and duration of exposure. More than 70 papers on the effects of inorganic suspended sediments on freshwater and marine fish and other organisms were reviewed to compile a data base on such effects. Regression analysis indicates that concentration alone is a relatively poor indicator of suspended sediment effects (r ² = 0.14, NS). The product of sediment concentration (mg/L) and duration of exposure (h) is a better indicator of effects (r ² = 0.64, P < 0.01). An index of pollution intensity (stress index) is calculated by taking the natural logarithm of the product of concentration and duration. The stress index provides a convenient tool for predicting effects for a pollution episode of known intensity. Aquatic biota respond to both the concentration of suspended sediments and duration of exposure, much as they do for other environmental contaminants. Researchers should, therefore, not only report concentration of suspended sediment but also duration of exposure of aquatic biota to suspended sediments.
The high visual resolution of a fast moving object or an instantaneous image by animals requires that they have a low optic critical duration. The freshwater bluegill showed the ability to detect an image displayed for 3.2 μs at contrast 67.1. The same image was undetectable by the human eye. The optic critical duration and the contrast threshold in the bluegill were found to be that of man. In terms of time scale and contrast, the visual ability of the bluegill seems far beyond that of a human, and it is more able to see approaching divers and fishing gears in the scattering medium of freshwater lakes.
Resource managers need to predict effects of pollution episodes on aquatic biota, and suspended sediment is an important variable in considerations of freshwater quality. Despite considerable research, there is little agreement on environmental effects of suspended sediment as a function of concentration and duration of exposure. More than 70 papers on the effects of inorganic suspended sediments on freshwater and marine fish and other organisms were reviewed to compile a data base on such effects. Regression analysis indicates that concentration alone is a relatively poor indicator of suspended sediment effects (r = 0.14, NS). The product of sediment concentration (mg/L) and duration of exposure (h) is a better indicator of effects (r = 0.64, P < 0.01). An index of pollution intensity (stress index) is calculated by taking the natural logarithm of the product of concentration and duration. The stress index provides a convenient tool for predicting effects for a pollution episode of known intensity. Aquatic biota respond to both the concentration of suspended sediments and duration of exposure, much as they do for other environmental contaminants. Researchers should, therefore, not only report concentration of suspended sediment but also duration of exposure of aquatic biota to suspended sediments.
Yearling coho salmon Oncorhynchus kisutch and steelhead Salmo gairdneri were exposed to high (2–3 g/L) or low (0.4–0.6 g/L) concentrations of three kinds of suspended solids (topsoil, kaolin clay, and volcanic ash) as long as 7–8 d. Such exposure did not cause mortality, but plasma cortisol concentrations were temporarily elevated in both species after exposure to 2–3 g/L of suspended topsoil, indicating that such exposure may have been stressful to the fish. Feeding rates of both species were reduced at high exposure concentrations. Exposure of yearling steelhead for 2 d to high or low concentrations of suspended topsoil, kaolin clay, or volcanic ash induced similar elevations of plasma cortisol levels, and, in groups exposed to high concentrations, blood hematocrits were increased. Osmoregulatory performance in fresh water and after transfer to 26‰ seawater was unaffected, and gill tissue appeared normal, after exposure to suspended solids. Exposure of yearling steelhead to high concentrations of suspended topsoil reduced the fishes' tolerance of subsequent infection by the bacterial pathogen Vibrio anguillarum. These results suggest that coho salmon and steelhead can survive exposure to high concentrations of suspended solids, but may undergo sublethal physiological stress that reduces their performance capacity.
We investigated the effect of turbidity on the foraging behaviour of juvenile chinook salmon (Oncorhynchus tshawytscha) in the laboratory. We assessed visual ability by measuring the reaction distance of juvenile chinook to planktonic adult Artemia prey. Chinook exhibited a log-linear decline in reaction distance with increasing turbidity. These results were similar to those obtained by workers for other species. We also determined the effect of turbidity on the foraging rate of juvenile chinook for surface (Drosophila), planktonic (Artemia), and benthic (Tubifex) prey across a range of turbidity levels (< 1,18, 35, 70, 150, 370, 810 NTU). Foraging rates were reduced at higher turbidities for all three prey. However, for surface and benthic prey, foraging rates were also low in clear water, while highest rates were attained at intermediate turbidity levels (35–150 NTU). We suggest that increased feeding rate in turbid conditions reflects a reduced potential risk to predators.
The territorial, gill-flaring, and feeding behavior of juvenile coho salmon (Oncorhynchus kisutch) in a laboratory stream was disrupted by short-term exposure to suspended sediment pulses. At the higher turbidities tested (30 and 60 nephelometric turbidity units (NTU)), dominance hierarchies broke down, territories were not defended, and gill flaring occurred more frequently. Only after return to lower turbidities (0–20 NTU) was social organization reestablished. The reaction distance of the fish to adult brine shrimp decreased significantly in turbid water (30 and 60 NTU) as did capture success per strike and the percentage of prey ingested. Implications of these behavioral modifications suggest that the fitness of salmonid populations exposed to short-term pulses of suspended sediment may be impaired.
Fish activity was monitored analyzing the catches of gillnets exposed for short time intervals at night. Experiments were done in two Central European reservoirs with different turbidity and fish density. Cyprinids dominated in both reservoirs. The aims of the study were to describe and model a pattern of fish activity in general and on species and age group levels, and in turbid and clear water. Fish activity showed two distinct peaks around sunset and sunrise and was low during night. This pattern was the same in clear and turbid reservoirs, as well as for all species and age groups tested. This study established some justifications and standards for gillnet sampling: (i) it is possible to compare overnight gillnet catches between different lowland European species and waterbodies, as the pattern of fish activity is general; (ii) gillnets should be set 2–3h before sunset and lifted 2–3h after sunrise to cover activity peaks, thus getting reliable and comparable results; (iii) depicting gillnet catches per average hour of exposition produces biased and incomparable results.
Abstract Optimal behavioural strategies of aquatic organisms may change with environmental conditions such as turbidity. It was hypothesised that pike, Esox lucius L., adapts to low visibility and potential-reduced foraging opportunities by an increase in activity and pelagic residence in turbid conditions. Diel activity and habitat use of pike (57–85 cm) were studied in a turbid lake and a clear-water lake by tracking 31 radio-tagged pike during two diurnal tracking sessions in June 2006. A significant interaction between lake and total length of pike was found, suggesting a higher activity level in large pike in the turbid lake. In addition, pike exhibited a higher among-individual variance in movement and habitat use in the turbid lake. These results suggest a higher degree of behavioural diversity in pike in the turbid lake as a response to low visibility and a resulting change in foraging conditions.
1. Habitat degradation and biological invasions are important threats to fish diversity worldwide. We experimentally examined the effects of turbidity, velocity and intra- and interspecific competition on prey capture location, reactive distance and prey capture success of native rosyside dace (Clinostomus funduloides) and invasive yellowfin shiners (Notropis lutipinnis) in Coweeta Creek, North Carolina, U.S.A.
2. Increased turbidity and velocity produced significant decreases in the number of prey captured forward of the fish’s location. It is possible that this represents an increase in the amount of energy expended per prey captured.
3. We used Akaike’s Information Criterion (AIC) to evaluate competing explanatory models for reactive distance (10 generalised linear models, GLM) and prey capture success (9 generalised linear mixed models, GLMM).
4. Reactive distance decreased by 12% with an increase from 2 to 4 conspecifics, whereas a 10 NTU increase in turbidity reduced reactive distance by 9%. Capture success was affected by velocity, dominance and competition, and varied among species. A 6 cm s−1 increase in velocity produced a 28% decline in capture probability; however, dominant fish were 3.2 times more likely to capture a prey item than non-dominant fish. Yellowfin shiners only were 0.62 times as likely to capture a prey item as rosyside dace. Both intra- and interspecific competition reduced capture probability, and fish in high density intraspecific or interspecific trials were 0.46 times and 0.44 times as likely to capture prey, respectively, as fish in two fish intraspecific trials.
5. These results suggest behavioural variables are as important as physical factors in determining reactive distance and capture probability by these minnows.
Quantitative analyses of the effects of temporary blindfolding (BL) or lateralis section (LS) on the schooling performance of saithe (Pollachius virens) are reported. Comparison of effects of the sensory deprivations on school structure and dynamics allow determination of the relative roles of the lateral lines and vision in normal schooling. Extended 3-dimensional records were made of the positions of sensorily deprived individuals in normal schools as well as whole schools with sensory treatments.1.
Blinding had little effect on the position experimental fish took up with respect to their neighbors within the school (Fig. 2). In contrast, lateralis section resulted in a great increase in the frequency of neighbors at 90 bearing (directly alongside) (Fig. 2).
2.
Both BL and LS fish exhibited different characteristic nearest neighbor distances (NNDs) than controls, with blinding increasing NND and lateralis section decreasing NND (Fig. 4).
3.
Importance of the lateral line in transmission of a fright response and sudden velocity changes within a school is demonstrated by experiments in which schools were intentionally startled. In schools of LS fish there exist significant relationships between latency to startle and the distance and angle between a fish and the startling object. Such relationships are not seen in normal schools: with intact lateral lines, fish respond with similar latencies to objects in all directions (Fig. 5).
4.
Fish which are blindfolded are able nonetheless to match short-term changes in velocity of their neighbors and actually show higher correlations than do controls (Fig. 8 b). Lateralis section does not reduce correlations between fish and neighbors (Fig. 8 d) probably because LS fish take up positions at which they can best determine neighbors' velocities by vision alone.
We conclude that the role of the lateral line in schooling is much greater than has been recognised previously. Our experiments suggest that characteristic NND in a travelling school is maintained by opposing forces of attraction and repulsion mediated by stimuli perceived by the visual and lateralis systems respectively. School structure and dynamics depend upon both senses, with vision primarily important for the maintenance of position and angle between fish and the lateral lines primarily important for monitoring the swimming speed and direction of travel of neighbors.