Energetics and metabolic correlates of starvation in juvenile perch (Perca fluviatilis)

Long-term measurements of the diurnal pattern of oxygen consumption were conducted in fasting juvenile perch at 15 and at 20° C. In addition, dry body mass, protein and glycogen concentrations and the activity of two key enzymes of energy metabolism, phosphofructokinase and glutamate pyruvate transaminase, were monitored during the period of food deprivation. The average rate of oxygen consumption decreased during the starvation period, but the regular diurnal pattern of low rates in the dark and high rates in the light was upset by a break around days 7 to 8 at both temperatures. This break coincided with the exhaustion of the glycogen reserves in the muscles and in the liver, indicating that switching to a new energetic fuel was accompanied by a change in the pattern of swimming activity. Choice of the major energy source after exhaustion of the carbohydrate store was substantially influenced by water temperature. A negative correlation was found between the scope for spontaneous activity and the specific rate of oxygen consumption in the dark phase suggesting that the resting rate of metabolism responded more strongly to food deprivation than the rate of spontaneous activity in the light phase.     

Oxygen consumption, ammonia excretion and protein use in response to thermal changes in juvenile Atlantic salmon Salmo salar

Experiments were designed to examine the effects of various temperature challenges on oxygen consumption and ammonia excretion rates and protein utilization in juvenile Atlantic salmon Salmo salar . Fish acclimated to 15° C were acutely and abruptly exposed to either 20 or 25° C for a period of 3 h. To simulate a more environmentally relevant temperature challenge, a third group of fish was exposed to a gradual increase in temperature from 15 to 20° C over a period of 3 h ( c. 1·7° C h⁻¹). Oxygen consumption and ammonia excretion rates were monitored before, during and after the temperature shift. From the ammonia excretion and oxygen consumption rates, protein utilization rates were calculated. Acute temperature changes (15–20° C or 15–25° C) caused large and immediate increases in the oxygen consumption rates. When the temperature was gradually changed ( i.e. 1·7° C h⁻¹), however, the rates of oxygen consumption and ammonia excretion were only marginally altered. When fish were exposed to warmer temperatures ( i.e. 15–20° C or 15–25° C) protein use generally remained at pre-exposure (15° C) levels. A rapid transfer back to 15° C (20–15° C or 25–15° C) generally increased protein use in S. salar . These results indicate that both the magnitude and the rate of temperature change are important in describing the physiological response in juvenile salmonids.     

Swimming metabolism and temperature in juvenile walleye,Stizostedion vitreum vitreum

Synopsis Oxygen consumption of juvenile walleye increased between 5 and 15°C at each swimming speed between 20 and 45 cm s^–1. With further increase in temperature to 23.5°C, oxygen consumption declined. Basal oxygen consumption was estimated by extrapolation of the relationship between swimming speed and the logarithm of oxygen consumption to 0 cm s^–1. The metabolic cost of swimming, represented by the difference between total and basal oxygen consumption was independent of temperature at each swimming speed. Energy required to swim 1 km increased from 2.14 to 5.68 J g^–1 between 20 and 45 cm s^–1.     

Metabolic rate and cost of growth in juvenile pike (Esox lucius L.) and perch (Perca fluviatilis L.): the use of energy budgets as indicators of environmental change

Summary Energy budgets of juvenile pike and perch (weighing approximately 3 g) were determined in experiments lasting up to 4 days, by simultaneously measuring oxygen consumption, food consumption, and growth of individual fish. Although the basic pattern of energy allocation was identical in the two species, perch subjected to constant light (PEL) showed faster growth, higher assimilation and conversion efficiency, and higher oxygen consumption than perch subjected to a short daylength regime (PED). The efficiency with which food energy was converted into body mass was 39±5% in PED but 49±4% in PEL. However, the “work coefficient” (increment of body mass/post-prandial increase of oxygen consumption: mg · μmol O _inf2 ^sup−1 ) differed only insignificantly between the two groups of perch, indicating that the metabolic cost of growth was unaffected by the manipulation of experimental conditions. This identifies the higher assimilation efficiency, i.e. the increased flow of food energy into the tissues as being the cause of accelerated growth of perch under the constant-light regime. In both species the maximum feeding-induced metabolic rate was 4 times higher than the lowest preprandial rate. In perch (which were kept on low rations before the experiments) the post-prandial metabolic rate increased steadily from day to day during the 4-day experiments, so that on the last day the rate of oxygen consumption exceeded the rate on the first day by about 41%. This investigation provides further evidence that the allocation of metabolic energy in fish is based on a flexible strategy which responds sensitively to changes in both internal and external conditions.     

Growth, pigmentation and activity of juvenile Japanese eels in relation to temperature and fish size

The growth and activity of juvenile Japanese eels Anguilla japonica in different pigmentation stages from the glass eel to the elver stage were studied in the laboratory at 15, 20 and 25° C. The growth and activity of the eels were significantly influenced by both temperature and fish size. Growth rate generally declined with increasing fish size, and fish were least active and experienced a low growth during the pigmenting stage at all temperatures. They were nocturnal and spent significantly more time moving (swimming, feeding and moving over the substratum) at 20 and 25° C than at 15° C at night within each pigmentation stage. Accordingly, they grew significantly faster at 20 and 25° C than at 15° C throughout the study. The development of pigmentation appeared to be dependant on water temperature but not on fish size. This study suggested that the growth and activity of juvenile Japanese eels were positively correlated, because fish were least active and grew slowest at low temperature (15° C) or during the pigmenting stage at all temperatures.     

Assessment of cardiac output as a predictor of metabolic rate in rainbow trout

When water temperature was increased from 12 to 27°C at a rate of 2°C h⁻¹, oxygen consumption of rainbow trout Oncorhynchus mykiss was correlated strongly with both heart rate and blood oxygen extraction but the relationship with cardiac output was variable and weak. On the other hand, when water temperature was decreased from 21 to 12°C at a rate of 0·5°C h⁻¹, oxygen consumption was correlated with both heart rate and cardiac output but not with blood oxygen extraction. When fish were forced to swim increasingly faster, heart rate, cardiac output and blood oxygen extraction all correlated positively with oxygen consumption. For both cardiac output and heart rate, the slope of the regression line with oxygen consumption was elevated significantly more when the fish were forced to swim at increasingly higher swimming speeds than when water temperature was increased or decreased. The variation of the regression lines between cardiac output and oxygen consumption indicated that cardiac output presents few advantages over heart rate as a predictor of metabolic rate.     

不同流速下杂交鲟幼鱼游泳状态与活动代谢研究

为研究水流速度对杂交鲟幼鱼行为和代谢的影响,探讨游泳状态与活动代谢及相关游泳运动参数之间的关系,在26℃水温下,使用特制的鱼类游泳行为和活动代谢同步测定装置,测定了杂交鲟幼鱼在0.1、0.3、0.5 m/s三种流速和静水条件下的游泳状态、趋流率、摆尾频率和耗氧率。结果表明:随着流速的增大,杂交鲟幼鱼逆流前进和逆流静止游泳状态所占时间比例显著减少,而逆流后退所占时间比例显著增加,顺流而下时间比例有所上升。在0.0—0.3 m/s的流速范围内,杂交鲟幼鱼各个时段的平均趋流率、摆尾频率和耗氧率均随着流速的增加而增大,在0.3 m/s流速下分别达到100%﹑(2.53±0.34)Hz和(490.99±164.59)mg O2/(kg.h)。当流速增加至0.5 m/s时,在趋流率仍保持100%的情况下,其耗氧率相比0.3 m/s增加了21.86%,而摆尾频率却减小了6.70%。实验过程杂交鲟幼鱼趋流率与摆尾频率呈显著线性正相关,而摆尾频率与耗氧率在大部分时段却无相关性。随着时间的延长,各流速组杂交鲟幼鱼趋流率、摆尾频率和耗氧率呈现不同的变化趋势,其趋流率均相对稳定;但摆尾频率均随时间延长呈下降趋势,而耗氧率则在实验前9h随时间延长逐渐增加,随后趋于稳定。研究结果提示:杂交鲟幼鱼游泳状态的变化与流速有关,而反映运动强度大小的摆尾频率与活动代谢率的关系受到游泳状态的显著影响,同时也与运动代谢特征的时间变化有关。       

A new type of metabolism chamber for the determination of active and postprandial metabolism offish, and consideration of results for coregonid and salmon juveniles

The optomotor reaction of juvenile Coregonus schinzipalea Val. et Cuv. and Salmo salar L. was utilized to develop a circular tube metabolism chamber to measure oxygen consumption and ammonia excretion as a function of swimming speed. The metabolism chamber with a constant water flow assured the maintenance of stable conditions. The unidirectional movement of fish was measured in a circular tube with a single narrowing. The relationships between the swimming speed and oxygen consumption or ammonia excretion described by exponential equations allowed the extrapolation towards the standard metabolism, i.e., zero swimming speed. For a juvenile coregonid (0.1–0.15 g individual weight, 2.6–2.8 cm total length) standard metabolism at 14° C was estimated as 0.65 mg0₂ g⁻¹ h⁻¹ and 17.3 μg N(NH₃)g⁻¹ h⁻¹, whereas for juvenile salmon (136mg individual weight) respective values at 22° C were 0.047mg0₂g⁻¹h⁻¹ and 0.61 μg N(NH₃)g⁻¹ h⁻¹. The feeding test with juvenile salmon was also performed in this circular chamber, and in both energy and nitrogen budgets after a meal the partitioning could be precisely attributed to standard metabolism, active metabolism and specific dynamic action (in the case of oxygen consumption) or postprandial nitrogen increase.
The new metabolism chamber allowed the relationship between metabolism and swimming velocity of juvenile fish with developed rheotactic response. It could be used with adult fish for similar purposes.     

Energetic costs at different levels of feeding in juvenile cod, Gadus morhua L.

The energetic costs associated with feeding by juvenile cod were determined by means of an open-circuit respirometer. Fish acclimated to several temperatures (7, 10, 15 and 18°C) were kept at natural lighting levels, and fed inside their individual respirometers. They consumed a diet compounded from natural foods, at five different ration levels, their oxygen consumption being monitored continually over an 11–16 day period.
After each meal the rate of oxygen consumption increased to above the pre-feeding level, reaching a peak 8–10 h later. With each successive meal the oxygen consumption showed a cumulative increase, reaching a maximum usually after the last meal.
The elevation in metabolic rate associated with feeding was dependent upon ration size, increasing linearly as the food intake increased. The effect was also dependent upon temperature; for fish fed to satiation the total energy cost was equivalent to 11.9, 10.9, 16.4 and 17.1% of the ingested energy at 7, 10, 15 and 18°C respectively. For resting satiated fish the rate of oxygen consumption was close to the maximum rate for active fish.     

Metabolism and photoperiod in juvenile lake charr and walleye

Synopsis Basal and swimming oxygen consumption of juvenile lake charr (8 and 12°C and walleye (8°C) were measured for fish exposed either to a natural or constant photoperiod. Seasonal changes in oxygen consumption were not demonstrable at the basal level or for swimming at comparable speeds between 20 and 45 cm s^–1. The absence of a seasonal change in oxygen consumption among juvenile fish is in marked contrast to the seasonal pattern described in other studies at the basal and active level in mature fish.     

The relationship between growth, food conversion and oxygen consumption in developed and underdeveloped American eels, Anguilla rostrata Lesueur

This study examined the influence of body size and temperature on oxygen consumption and food converstion in juvenile American eels ( Anguilla rostrata ). The weight-specific oxygen consumption rate for underdeveloped eels (18 months old) was significantly higher than the weight-specific oxygen consumption rate of developed eels of the same weight (6 months old). Oxygen consumption rates increased linearly with weight at each experimental temperature (15, 20, 25°C) when data were transformed logarithmically. No significant differences were found among slopes oflog transformed data at varying temperatures. Oxygen consumption was significantly higher at night (2300 h) as compared to morning (0900 h). The results indicate that underdeveloped eels use more energy and use less food less efficiently than developed eels.     

Effects of temperature, hypoxia and activity on the metabolism of juvenile Atlantic cod

Standard metabolic rate (SMR), active metabolic rate (AMR) and critical oxygen saturation ( S_crit ) were measured in Atlantic cod Gadus morhua at 5, 10 and 15° C. The SMR was 35.5, 57.0 and 78.2 mg O₂ kg⁻¹ h⁻¹ and S_crit was 16.5, 23.2 and 30.3%, at 5, 10 and 15° C, respectively. Previously reported SMR for Atlantic cod from arctic waters at 4° C was twice that measured at 5° C in the present study. A possible intraspecific latitudinal difference in the SMR is discussed. The AMR was 146.6, 197.9 and 200.4 mg O₂ kg⁻¹ h⁻¹ and the critical swimming speed ( U_crit ) was 1 6, 1.7 and 1.9 at 5, 10 and 15° C, respectively. The maximum oxygen consumption was found to be associated with exercise, rather than recovery from exercise as previously reported in another Study of Cod metabolism.     

Effects of acute temperature change on the metabolism and swimming ability of juvenile sterlet sturgeon (Acipenser ruthenus,Linnaeus 1758)

The objective of this study was to provide information on changes in the metabolism and swimming ability of juvenile sterlet sturgeon, Acipenser ruthenus, caused by acutely low or high temperatures. Changes in critical swimming speed (U_crit), oxygen consumption rate (MO₂), tail beat frequency (TBF) and tail beat amplitude (TBA) were observed with a Steffensen‐type swimming respirometer, an oxygen electrode and a camera at different swimming speeds at three temperatures: 5°C, 15°C, and 25°C. Fish tested at 5°C and 25°C were maintained at 15°C (near optimal) for one week to simulate conditions below a dam. The U_crit value decreased significantly during acute temperature changes at 5°C and 25°C; U_crit was highest near the optimal temperature. Oxygen consumption rate (MO₂) increased with the swimming speed at 15°C; however, at 25°C and 5°C, the MO₂ decreased with the swimming speed. Both TBA and TBF decreased at 5°C and 25°C compared to values at 15°C. The slopes of the regression lines (TBF/U) at 5°C and 25°C seemed lower compared to 15°C.     

Effect of repeated exercise fatigue on the swimming performance of juvenile rock carp (Procypris rabaudi,Tchang)

The swimming performance of juvenile rock carp (Procypris rabaudi, Tchang) subjected to repeated fatigue exercise was studied using a flume-type respirometer at 20°C. The critical swimming speed (U_crit) and oxygen consumption rate (MO₂) of juvenile rock carp were measured during two successive stepped velocity tests, following a 60 min rest interval. U_crit of rock carp was giving a recovery ratio (R_r) of 92.64%, and exertion exercise decreases U_crit. When MO₂ was plotted as a linear function of U, the slope for trial 1 was 1.06 and 1.50 for trial 2, indicating a decreasing in swimming efficiency. The maximum metabolic rate (MMR) increased from 17.06 ± 1.14 mmol O₂/(kg·hr) to 19.14 ± 1.23 mmol O₂/(kg·hr), and the exercise post oxygen consumption rate (EPOC) increased from 9.00 to 9.65 mmol O₂/kg. Repeated fatiguing exercise increased both the aerobic and anaerobic cost of reaching U_crit, but anaerobic metabolism accounted for a larger proportion in the trial 2. The data investigation on the swimming performance and the physiological response to fatigue provide important design criteria for fishways.     

Effects of temperature, irradiance, and daylength on the marine diatom Leptocylindrus danicus Cleve. III. Dark respiration

Oxygen consumption in the dark by the marine diatom Leptocylindrus danicus Cleve was measured in batch culture under 49 combinations of temperature (5, 10, 15, 20°C), daylength (15:9, 12:12, 9:15 LD), and irradiance (at least four irradiances per daylength). Dark respiration was influenced by previous light history and temperature. Elevated respiration rates characterized cells grown under higher irradiances at 10, 15, and 20°C; the effects of previous light history were more evident at higher temperatures. At 5°C, oxygen consumption was unaffected by growth irradiance. The highest respiration rates were measured at 20°C; the Q₁₀ value for dark respiration (5 to 20°C) was 4.0. Daylength affected oxygen consumption at 15 and 20°C. The mean R:P ratio in all experiments was 0.139, with lower ratios at higher temperatures and irradiances, and higher ratios at lower temperatures and irradiances. The R:P ratio was unaffected by daylength. Carbon-specific respiration rates exceeded excretion losses in all experiments except under high irradiances at 5°C. The E:R ratio was smaller at lower irradiances and higher temperatures; daylength effects were not evident.     

Behavioural studies on the lesser sandeel Ammodytes marinus (Raitt) III. The effect of temperature on activity and the environmental control of the annual cycle of activity

The behaviour of the lesser sandeel, Ammodytes marinus (Raitt), has been investigated at 5, 10 and 15° C, using a photographic method of recording activity. The activity patterns at 10 and 15° C were very similar, there being a high level of swimming activity during the light period, which fell to a low level at 5° C. It was also lower at 10° C at the end of the experiment than at the beginning and it is suggested that this might have been due to an increase in the fat contents of the fish. The feeding rate of the fish was measured and showed a Q ₁₀ of 2.08 for the temperature range 5–15° C. The annual cycle of activity of A. marinus is discussed in relation to seasonal changes in food availability, light and temperature, and in the fat content of the fish. It is concluded that after spawning in the December–January period the fish remain buried in the sand until April, because of the limiting effect on swimming and feeding activity of the environmental factors in the intervening period. The proportion of fish available for capture at the start of the fishery in April is related mainly to temperature, but food (as measured by numbers of copepods) light intensity and photoperiod are by then increasing rapidly. After July the fishery ceases and it is thought that this is because the fish have entered an overwintering stage, during which they remain buried in the sand. This phase is also thought to be associated with the maturation of the gonads in readiness for the winter spawning. The factors causing the fish to enter this stage are as yet undetermined but may be related to the attainment of a certain level of fat content.     

Aerial and aquatic oxygen consumption of Monodonta turbinata (Mollusca: Gastropoda)

The midlittoral trochid, Monodonta turbinata (Born) has a higher rate of oxygen consumption in air than in water at temperatures between 15 and 25°C. The temperature coefficient of its oxygen consumption is higher for the temperature interval 15 to 25°C than it is for the interval 5 to 15°C. The aerial oxygen consumption is increased by forced emersion or immersion for 24 hours. Immersion has the greater effect. It would appear that the trochid shows respiratory adaptation to zonation and environmental temperature.     

THE INFLUENCE OF TEMPERATURE ON THE SURVIVAL OF SEVERAL SPECIES OF FISH IN LOW TENSIONS OF DISSOLVED OXYGEN

The resistance to low tensions of dissolved oxygen over periods ranging from less than a day to a week was determined for rainbow trout ( Salmo gairdnerii Richardson), perch ( Perca fluviatilis L.), roach ( Rutilus rutilus (L.)), and mirror carp, a domestic form of the common carp ( Cyprinus carpio L.) at 10°, 16° and 20°C., tench ( Tinea tinea (L.)) at 10° and 16°C., dace ( Leuciscus leuciscus (L.)) at 16° and 20°C., chub ( Squalius cephalus (L.)) at 20°C., and bleak ( Alburnus alburnus (L.)) at 16°C.
At each temperature period of survival decreased with fall in oxygen tension.
Rise in temperature between 10° and 20°C. reduced resistance to lack of oxygen of all species except rainbow trout, in which there was no significant difference between resistance at 16° and 20°C. Rise in temperature between 10° and 16°C. did, however, lower resistance considerably.
Tench were the most resistant to lack of oxygen and, in general, trout were the most susceptible. At 20°C. mirror carp required a higher tension of oxygen to enable them to survive for a week than did rainbow trout, but for shorter periods could withstand much lower tensions than rainbow trout; at 10° and 16°C. their resistance was intermediate between that of tench and rainbow trout.     

Thermally induced phenotypic plasticity of swimming performance in European sea bass Dicentrarchus labrax juveniles

The vulnerability of embryonic and larval stages of European sea bass Dicentrarchus labrax to environmental temperature and the longer-term consequences for the early juveniles was demonstrated. This phenotypic plasticity was highlighted by subjecting D. labrax at 15·2 ± 0·3 or 20·0 ± 0·4° C (mean ± s . d .) up to metamorphosis and then at the same temperature (18·5 ± 0·7° C). After 4–6 weeks at the same temperature, the measurement of critical swimming speed at four exercise temperatures (15, 20, 25 and 28° C) showed a significantly higher swimming capacity in the fish initially reared at 15° C than for fish initially reared at 20° C. This performance was correlated with significant differences in the phenotype of red muscle. Thermally induced phenotypic plasticity was clearly demonstrated as an important mechanism controlling swimming performance in early juveniles of D. labrax .     

The metabolic and biochemical responses of tropical whitespotted bamboo shark Chiloscyllium plagiosum to alterations in environmental temperature

The capacity of tropical whitespotted bamboo sharks Chiloscyllium plagiosum to metabolically compensate, at both the whole‐animal and biochemical levels, to prolonged exposure to temperatures higher (30° C) and lower (20 and 15° C) than their native temperature (24·5° C) was examined. As expected, whitespotted bamboo shark oxygen consumption increased upon exposure to 30° C and decreased at 20 and 15° C. Initial changes in oxygen consumption were maintained even after months at the experimental temperature, indicating that whitespotted bamboo sharks did not compensate metabolically to the experimental temperatures. Maximal activities and thermal sensitivity of citrate synthase and lactate dehydrogenase from whitespotted bamboo shark white locomotor muscle were similar between control animals maintained at 24·5° C and those maintained at 15° C, indicating that cold‐exposed animals did not compensate at the biochemical level. Similarly, lactate dehydrogenase activity did not change following prolonged exposure to 30° C. White muscle from whitespotted bamboo sharks maintained at 30° C had significantly lower citrate synthase activity than did control animals. This result was surprising given the lack of metabolic compensation at the whole‐animal level. Overall, whole‐animal oxygen consumption measurements supported the hypothesis that animals from thermally stable environments lacked the capacity to metabolically compensate to altered temperatures. Enzymatic results, however, suggested that the metabolic potential of muscle could change following temperature acclimation even in the absence of metabolic compensation at the whole‐animal level.