Swimming Activity Of Fish Research Articles

Effects of hanging ice dams on winter movements and swimming activity of fish

Formation of a hanging dam, a large, thick sub-surface accumulation of frazil ice that blocked river flow, altered physical environmental conditions dramatically and common carp Cyprinus carpio, and brown trout Salmo trutta, evacuated the pool in which the dam developed. A mean of 80·1% of the pool volume was filled with frazil ice. Mean and bottom water velocities in the pool increased from 6 to 27 cm s−1 and from 4 to 21 cm s−1, respectively, when the hanging dam formed, and water depth decreased from a mean of 2·25 to 0·45 m. Activity levels of fish leaving the pool varied. Two carp had higher swimming activities when in the over wintering pool, compared to the period when they were out of it, and a third showed opposite results.

Effects of hanging ice dams on winter movements and swimming activity of fish

Formation of a hanging dam, a large, thick sub‐surface accumulation of frazil ice that blocked river flow, altered physical environmental conditions dramatically and common carp Cyprinus carpio, and brown trout Salmo trutta, evacuated the pool in which the dam developed. A mean of 80·1% of the pool volume was filled with frazil ice. Mean and bottom water velocities in the pool increased from 6 to 27 cm s−1 and from 4 to 21 cm s−1, respectively, when the hanging dam formed, and water depth decreased from a mean of 2·25 to 0·45 m. Activity levels of fish leaving the pool varied. Two carp had higher swimming activities when in the over wintering pool, compared to the period when they were out of it, and a third showed opposite results.

Diel activity rhythm of seabass tracked in a natural environment: group effects on swimming patterns and amplitudes

Seabass swimming behavior was investigated in a salt-marsh area located along the Atlantic coast north of La Rochelle, France. Seabass is a natural inhabitant of this coastal zone and is farmed there as well. During its 3rd year, seabass can move about either singly or in small groups. Swimming activity of single fish and fish in a group was studied using an acoustic telemetry recording system. This study demonstrates that swimming activity levels and patterns of this species are modified by a group effect. Single fish were mainly nocturnal and fish in a group adopted a diurnal activity rhythm and lower maximum swimming activity levels.

Physiology and behaviour of free-swimming Atlantic cod (Gadus morhua) facing fluctuating temperature conditions

Atlantic cod (Gadus morhua L.), acclimated to 5 °C, were equipped with ultrasonic transmitters which allowed the continuous monitoring of their vertical movements and heart rate. Fish were then placed in a 125 m3 tower tank in which the various thermal conditions they encounter in their natural environment were reproduced. Physiological and behavioural responses of cod were followed in parallel to the induced environmental changes. The experimental conditions studied in the tower tank were also reproduced in a swimming respirometer, where oxygen consumption and heart rate could be monitored within the activity range of a free-swimming animal. In a homogeneous water column, a rise in temperature induced marked increases in fish swimming activity, heart rate and heart beat-to-beat variability. In a thermally stratified environment, voluntary activity also increased when the thermal structure of the water column was altered, though no temperature-dependent changes in heart rate were observed. In this case, fish avoided the new temperature conditions, exhibiting distinct thermoregulatory behaviour. Stratification of the water column also prompted daily cyclic changes in fish distribution, animals tending to be in deeper and colder water layers during the day and in shallower and warmer layers at night. Respirometry experiments revealed that the thermoregulatory behaviour observed in free-ranging fish was probably driven by the energetic expedient of maintaining the physiological status quo ­ i.e. avoiding bioenergically costly reacclimation processes. Indeed, acute temperature increases or decreases of 2.5 °C led to marked differences in oxygen consumption, with metabolic rate changes of 15 and 30 %, respectively. The persistent linear relationship between heart rate and oxygen consumption allowed us to estimate, from the heart rate recorded in free-swimming fish, the entire range of metabolic responses that cod underwent voluntarily while experiencing a thermally stratified water column. The most profound metabolic effect, however, was observed with feeding, when oxygen consumption increased by as much as 80 %, resulting in an estimated 90 % reduction in their subsequent scope for activity.

Daily and seasonal patterns in the feeding behaviour of Atlantic salmon ( Salmo salar L.) in a sea cage

The diurnal and seasonal variation in behavioural indices of appetite in one-sea-winter Atlantic salmon in a sea cage was investigated in relation to environmental variables and fish swimming activity, from autumn to spring. There was marked seasonal variation in feeding behaviour, indicating a reduction in appetite from autumn to winter and a rapid increase in appetite from late winter onwards. Seasonal variation in behavioural indices of appetite was more closely related to day length and change in day length, than to other environmental variables, including water temperature. A feeding regime based on the assumption that water temperature is the most important environmental determinant of the appetite of salmon in sea cages could lead to food wastage in autumn and early winter and under-feeding in late winter and early spring. The responsiveness of salmon to food varied significantly throughout the day, but the diurnal pattern of appetite was different at different times of year. In contrast to a previous study at the same site in summer, there were not marked morning and evening peaks of appetite, and pre-feeding swimming speed was not closely related to appetite.

SWIMMING BEHAVIOR AS AN INDICATOR OF SUBLETHAL TOXICITY IN FISH

Swimming behavior of fish is impaired by exposure to a diversity of contaminants. Gross aberrations in swimming can be qualitatively assessed while subtle changes in swimming behavior arising from sublethal exposures can be detected through a more detailed analysis of this response. Compared to other swimming behavior variables, the physical capacity to swim against water flow tends to be affected at relatively high toxicant concentrations and often presages mortality. Orientation to water flow, however, is altered at sublethal concentrations. Frequency of activity is a more sensitive measure in detecting contamination than measurements of survival alone. Alterations in swimming behavior have been detected during exposures to various contaminants at concentrations as low as 0.7 to 5% of their LC50 values and at concentrations that subsequently inhibited growth after longer periods of exposure. Analysis of swimming patterns provides even higher resolution for analysis of swimming behavior, and increased availability of the instrumentation necessary for such measurements should facilitate use of this approach. Fish swimming activity can easily be incorporated in test protocols to expand the sensitivity of standard toxicity tests.

Swimming behavior as an indicator of sublethal toxicity in fish

AbstractSwimming behavior of fish is impaired by exposure to a diversity of contaminants. Gross aberrations in swimming can be qualitatively assessed while subtle changes in swimming behavior arising from sublethal exposures can be detected through a more detailed analysis of this response. Compared to other swimming behavior variables, the physical capacity to swim against water flow tends to be affected at relatively high toxicant concentrations and often presages mortality. Orientation to water flow, however, is altered at sublethal concentrations. Frequency of activity is a more sensitive measure in detecting contamination than measurements of survival alone. Alterations in swimming behavior have been detected during exposures to various contaminants at concentrations as low as 0.7 to 5% of their LC50 values and at concentrations that subsequently inhibited growth after longer periods of exposure. Analysis of swimming patterns provides even higher resolution for analysis of swimming behavior, and increased availability of the instrumentation necessary for such measurements should facilitate use of this approach. Fish swimming activity can easily be incorporated in test protocols to expand the sensitivity of standard toxicity tests.

Avoidance behavior and swimming activity of fish to detect pH changes.

Usually, the initial response of an animal to an environmental perturbation is changing its behavior. With fish, this may hold an alteration in swimming activity or reactions like avoidance or attraction. The usefulness of fish behavior to detect the changes in chemical water quality was recognized more than 70 years ago. Since that time, many laboratory studies have been performed on the behavioral reactions of aquatic organisms to pollutants, including those resulting from pH changes. However, still there is no conclusive evidence that fish behavior offers an adequate tool to detect chemical pollution. In this study, the use of R-value for swimming activity and D/sup 2/-value for avoidance behavior of toxic warning methods to indicate the development of toxic condition is discussed based on experimental data on pH effects.

Circadian rhythm in brain catecholamine concentrations in the teleost: Anguilla anguilla L.

1. Whole-brain concentrations of norepinephrine (NE), epinephrine (E) and dopamine (DA) were measured in the teleost, Anguilla anguilla L. using spectrofluorimetric methods for a 24-hr period. 2. Average whole-brain concentrations were 0.14 ± 0.02 μg/g for E, 0.09 ± 0.02 μg/g for NE and 0.52 ± 0.08 μg/g for DA respectively. 3. A significant circadian variation was found for NE and DA. NE and DA were lower in the dark period than in daylight period. 4. It is suggested that catecholamine can interact in controlling the swimming activity of fish.

Effects of feeding and starvation on growth and swimming activity in an obligatory air-breathing fish

Reared in (tubular) aquaria containing different depths of water, Ophiocephalus striatus (0.7 g, 4.5 cm body length), an obligatory air-breathing tropical fish, swam long or short distances to enable themselves to exchange atmospheric air. In each tested depth (2.5, 5.0, 15.5, 31.0 and 40.0 cm) series, one group was starved, while the other was fed ad libitum twice a day on fish muscle. In the shallowest water (2.5 cm depth), the feeding group surfaced 1,294 times, travelling 64.7 m at an energy cost of 20.4 mg dry fish substance/g live fish/day, against those exposed to the deepest water (40 cm depth), which expended 35.8 mg/g/day, swimming 1,503.4 m on 1,879 visits to the surface. The starving group surfaced only 482 times, travelling 24.1 m at an expense of 5.8 mg/g/day in the shallowest water, while those at 40 cm depth surfaced 504 times, swimming 403.2 m at an energy cost of 7.4 mg/g/day. Owing to the sustained swimming activity and the consequent fatigue, the test individuals belonging to both groups in all the tested series ‘hang’ to the surface for a definite interval, repaying the O2 debt. Observations were also made to assess the duration of ‘hanging’ to precisely estimate the distance travelled. Irrespective of changes in depths of water, the duration of ‘hanging’ to surface was only 3.0 hr/day for the feeding groups, while it was as much as 15.5 hr/day for the starving groups. The maximum sustained metabolic level of O.striatus reared in 40 cm depth was equivalent to 1.23 ml O2/g/hr, which is about 2 times higher than the value reported for the active metabolism of swimming Oncorhynchus nerka at 15°C in Brett's (1964) respirometer. O.striatus reared in 2.5 cm depth fed 32.0 mg and converted 6.7 mg dry food/g live fish/day, while those exposed to the deepest water fed 49.1 mg, but converted only 5.5 mg/g/day. Culturing obligatory air-breathing fishes in shallow waters will be advantageous.

A small sonic tag for measurement of locomotor behaviour in fish

A technique for measuring the patterns and levels of swimming activity of unrestrained fish in their natural environment during a period of 24 h is described. The fish were marked with small tags which emitted continuous ultrasonic signals by which they could be located and tracked using submerged, remotely controlled, directional hydrophones. Preliminary results obtained from 2 brown trout (Sahno trutta) showed a pronounced diurnal activity pattern and remarkably low swimming activity levels.